Form 8-K

8-K — PTC THERAPEUTICS, INC.

Accession: 0001104659-26-075731

Filed: 2026-06-18

Period: 2026-06-18

CIK: 0001070081

SIC: 2834 (PHARMACEUTICAL PREPARATIONS)

Item: Entry into a Material Definitive Agreement

Item: Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant

Item: Unregistered Sales of Equity Securities

Item: Other Events

Item: Financial Statements and Exhibits

Documents

8-K — tm2618266d1_8k.htm (Primary)

EX-4.1 — EXHIBIT 4.1 (tm2618266d1_ex4-1.htm)

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8-K — FORM 8-K

8-K (Primary)

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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of

the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported):

June 18, 2026

PTC

THERAPEUTICS, INC.

(Exact Name of Company as Specified in Charter)

Delaware

001-35969

04-3416587

(State

or Other Jurisdiction

(Commission

(IRS

Employer

of Incorporation)

File

Number)

Identification

No.)

500

Warren Corporate Center Drive

Warren,

07059

(Address

of Principal Executive Offices)

(Zip

Code)

Registrant’s telephone number, including

area code: (908) 222-7000

Not applicable

(Former Name or Former Address, if Changed Since

Last Report)

Check the appropriate box below if the Form 8-K

filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see

General Instruction A.2. below):

¨ Written

communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

¨ Soliciting

material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

¨ Pre-commencement

communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

¨ Pre-commencement

communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the

Act:

Title

of each class

Trading

Symbol(s)

Name

of each exchange on which registered

Common

Stock, $0.001 par value per share

PTCT

Nasdaq

Global Select Market

Indicate by check mark whether the registrant is an emerging growth

company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities

Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ¨

If an emerging growth company, indicate by check mark if the registrant

has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant

to Section 13(a) of the Exchange Act. ¨

Item 1.01.

Entry into a Material Definitive Agreement.

On June 18, 2026, PTC Therapeutics, Inc. (the “Company”)

completed its previously announced private offering of $550,000,000 aggregate principal amount of its 0.0% Convertible Senior Notes due

2031 (the “Notes”) and entered into an indenture with U.S. Bank Trust Company, National Association, as trustee (the “Trustee”),

governing the Notes (the “Indenture”). The Notes were sold in a private placement under a purchase agreement, dated as of

June 15, 2026, entered into by and between the Company and Morgan Stanley & Co. LLC, as representative of the several initial

purchasers named in the purchase agreement (collectively, the “Initial Purchasers”), for resale to persons reasonably believed

to be qualified institutional buyers pursuant to Rule 144A under the Securities Act of 1933, as amended (the “Securities Act”).

The aggregate principal amount of the Notes sold reflects the exercise in full by the Initial Purchasers of their option to purchase up

to an additional $50,000,000 in aggregate principal amount of the Notes.

The Notes will not bear regular interest, and the principal amount

of the Notes will not accrete. The Notes may bear special interest under specified circumstances relating to the Company’s failure

to comply with its reporting obligations under the Indenture or if the Notes are not freely tradeable as required by the Indenture. Special

interest, if any, will be payable semiannually in arrears on June 15 and December 15 of each year, beginning on December 15,

2026 (if and to the extent that special interest is payable). The Notes will mature on June 15, 2031, unless earlier converted, redeemed

or repurchased pursuant to their terms.

The initial conversion rate of the Notes is 9.3042 shares of the Company’s

common stock, par value $0.001 per share (the “Common Stock”), per $1,000 principal amount of Notes (which is equivalent to

an initial conversion price of approximately $107.48 per share). The conversion rate will be subject to adjustment upon the occurrence

of certain specified events but will not be adjusted for any accrued and unpaid special interest. In addition, upon the occurrence of

a make-whole fundamental change (as defined in the Indenture) or an issuance of a notice of redemption, the Company will, in certain circumstances,

increase the conversion rate by a number of additional shares for a holder that elects to convert its Notes in connection with such make-whole

fundamental change or notice of redemption.

Holders may convert all or any portion of their Notes at their option

at any time prior to the close of business on the business day immediately preceding March 15, 2031 only under the following circumstances:

(1) during any calendar quarter commencing after the calendar quarter ending on September 30, 2026 (and only during such calendar

quarter), if the last reported sale price of the Common Stock for at least 20 trading days (whether or not consecutive) during a period

of 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter is greater

than or equal to 130% of the conversion price on each applicable trading day; (2) during the five business day period after any five

consecutive trading day period (the “measurement period”) in which the trading price per $1,000 principal amount of Notes

for each trading day of the measurement period was less than 98% of the product of the last reported sale price of the Common Stock and

the conversion rate on each such trading day; (3) if the Company calls any or all of the Notes for redemption, at any time prior

to the close of business on the second scheduled trading day immediately preceding the relevant redemption date; or (4) upon the

occurrence of specified corporate events. On or after March 15, 2031 until the close of business on the second scheduled trading

day immediately preceding the maturity date, holders may convert all or any portion of their Notes at any time, regardless of the foregoing

circumstances. Upon conversion, the Company will satisfy its conversion obligation by paying or delivering, as the case may be, cash,

shares of Common Stock or a combination of cash and shares of Common Stock, at the Company’s election.

The Company may not redeem the Notes prior to June 20, 2029. The

Company may redeem for cash all or any portion of the Notes, at the Company’s option, on or after June 20, 2029 if the last

reported sale price of the Common Stock has been at least 130% of the conversion price then in effect for at least 20 trading days (whether

or not consecutive) during any 30 consecutive trading day period (including the last trading day of such period) ending on, and including,

the trading day immediately preceding the date on which the Company provides a written notice of redemption at a redemption price equal

to 100% of the principal amount of the Notes to be redeemed, plus any accrued and unpaid special interest to, but excluding, the

redemption date. No “sinking fund” is provided for the Notes.

If the Company undergoes a fundamental change (as defined

in the Indenture) prior to the maturity date, then, subject to certain conditions, holders of Notes may require the Company to repurchase

for cash all or any portion of their Notes at a fundamental change repurchase price equal to 100% of the principal amount of the Notes

to be repurchased, plus any accrued and unpaid special interest to, but excluding, the fundamental change repurchase date.

The Notes are the Company’s general unsecured, senior obligations

and will rank senior in right of payment to any of its indebtedness that is expressly subordinated in right of payment to the Notes; equal

in right of payment with all of the Company’s existing and future unsecured indebtedness that is not so subordinated (including

any of the Company’s outstanding 1.50% Convertible Senior Notes due 2026 (the “Existing Convertible Notes”)); effectively

junior in right of payment to any of the Company’s senior, secured indebtedness to the extent of the value of the assets securing

such indebtedness; and structurally junior to all indebtedness and other liabilities (including trade payables) of the Company’s

current or future subsidiaries.

The Indenture contains customary events of default with respect to

the Notes, including that upon certain events of default (including the Company’s failure to make any payment of principal or any

special interest on the Notes when due and payable) occurring and continuing, the Trustee by written notice to the Company, or the holders

of at least 25% in principal amount of the outstanding Notes by notice to the Company and the Trustee, may (subject to the provisions

of the Indenture) declare 100% of the principal of and accrued and unpaid special interest, if any, on all the Notes to be due and payable.

In case of certain events of bankruptcy, insolvency or reorganization, involving the Company or a significant subsidiary, 100% of the

principal of and accrued and unpaid special interest, if any, on the Notes will automatically become due and payable without any further

act or declaration on the part of the holders or the Trustee. Upon such a declaration of acceleration, such principal and accrued and

unpaid special interest, if any, will be due and payable immediately.

The Company estimates the net proceeds from the offering to be approximately

$535.5 million, after deducting the Initial Purchasers’ discounts and commissions and the Company’s estimated offering expenses.

The Company is using approximately $328.8 million of the net proceeds from the offering to repurchase for cash $222.0 million in aggregate

principal amount of the Existing Convertible Notes pursuant to privately negotiated transactions with certain holders entered into concurrently

with the pricing of the offering of the Notes. The remaining net proceeds from the offering will

be used for general corporate purposes, which may include additional repurchases of the Existing Convertible Notes from time to time following

the offering and the repayment or retirement of any remaining Existing Convertible Notes at maturity.

The foregoing description of the Indenture and the Notes is a summary

only and is qualified in its entirety by reference to the text of the Indenture (and the Form of Note included therein), which is

attached as Exhibit 4.1 to this Current Report on Form 8-K and is incorporated herein by reference.

Item 2.03.

Creation of a Direct Financial

Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant.

The information set forth in Item 1.01 above is incorporated herein

by reference.

Item 3.02.

Unregistered Sales of Equity Securities.

The information set forth in Item 1.01 above is incorporated herein

by reference.

The Notes were sold to the Initial Purchasers in reliance on the exemption

from the registration requirements provided by Section 4(a)(2) of the Securities Act for resale to persons reasonably believed

to be qualified institutional buyers pursuant to Rule 144A of the Securities Act. The Company does not intend to file a registration

statement for the resale of the Notes or any Common Stock issuable upon conversion of the Notes. Additional information pertaining to

the Notes and the shares of Common Stock issuable upon conversion of the Notes is contained in Item 1.01 of this Current Report on Form 8-K

and is incorporated herein by reference.

Item 8.01.

Other Events.

The Company is using approximately $328.8 million of the net proceeds from

the offering to repurchase for cash $222.0 million in aggregate principal amount of the Existing Convertible Notes pursuant to privately

negotiated transactions with certain holders entered into concurrently with the pricing of the offering of the Notes. After

giving effect to such expected repurchases of the Existing Convertible Notes, the aggregate principal amount outstanding of Existing Convertible

Notes would be $55.5 million.

Item 9.01.

Financial Statements and Exhibits.

(d) Exhibits.

Exhibit

No.

Description

4.1

Indenture (including Form of Note), dated June 18, 2026, between PTC Therapeutics, Inc. and U.S. Bank Trust Company, National Association.

104

The cover page from this Current Report on Form 8-K, formatted in Inline XBRL

Cautionary Note Regarding Forward-Looking Statements

This Current Report on Form 8-K contains information about future expectations, plans

and prospects of the Company’s management that constitute forward-looking statements for purposes of the safe harbor provisions

under The Private Securities Litigation Reform Act of 1995, including statements with respect to the Company’s expectations with

respect to the repurchase of Existing Convertible Notes. Actual results may differ materially from those indicated by these forward-looking

statements as a result of various important factors including, but not limited to, the impact of general economic, industry, market or

political conditions and other factors that are discussed in the Company’s Annual Report on Form 10-K, Quarterly Reports on Form

10-Q, and other documents periodically filed with the Securities and Exchange Commission.

In addition, the statements in this Current Report

on Form 8-K represent the Company’s expectations and beliefs as of the date of this Current Report on Form 8-K. The Company anticipates

that subsequent events and developments may cause these expectations and beliefs to change. However, while the Company may elect to update

these forward-looking statements at some point in the future, it specifically disclaims any obligation to do so. These forward-looking

statements should not be relied upon as representing the Company’s expectations or beliefs as of any date subsequent to the date

of this Current Report on Form 8-K.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934,

the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

PTC Therapeutics, Inc.

Date: June 18, 2026

By:

/s/ Pierre Gravier

Pierre Gravier

Chief Financial Officer

EX-4.1 — EXHIBIT 4.1

EX-4.1

Filename: tm2618266d1_ex4-1.htm · Sequence: 2

Exhibit 4.1

Execution Version

PTC THERAPEUTICS, INC.

AND

U.S. BANK TRUST COMPANY, NATIONAL ASSOCIATION,

as Trustee

INDENTURE

Dated as of June 18, 2026

0% Convertible Senior Notes due 2031

TABLE OF CONTENTS

Page

Article 1

Definitions

Section 1.01 .

Definitions

Section 1.02 .

References to Interest

Article 2

Issue, Description, Execution, Registration And Exchange Of Notes

Section 2.01 .

Designation and Amount

Section 2.02 .

Form of Notes

Section 2.03 .

Date and Denomination of Notes; No Regular Interest;

Special Interest and Defaulted Amounts

Section 2.04 .

Execution, Authentication and Delivery of Notes

Section 2.05 .

Exchange and Registration of Transfer of Notes;

Restrictions on Transfer; Depositary

Section 2.06 .

Mutilated, Destroyed, Lost or Stolen Notes

Section 2.07 .

Temporary Notes

Section 2.08 .

Cancellation of Notes Paid, Converted, Etc

Section 2.09 .

CUSIP Numbers

Section 2.10 .

Additional Notes; Repurchases

Article 3

Satisfaction And Discharge

Section 3.01 .

Satisfaction and Discharge

Article 4

Particular Covenants Of

The Company

Section 4.01 .

Payment of Principal and Interest

Section 4.02 .

Maintenance of Office or Agency

Section 4.03 .

Appointments to Fill Vacancies in the Trustee’s

Role

Section 4.04 .

Provisions as to Paying Agent

Section 4.05 .

Existence

Section 4.06 .

Rule 144A Information Requirement and Annual

Reports

Section 4.07 .

Stay, Extension and Usury Laws

Section 4.08 .

Compliance Certificate; Statements as to Defaults

Section 4.09 .

Further Instruments and Acts

Article 5

Lists Of Holders And Reports By The Company And The Trustee

Section 5.01 .

Lists of Holders

Section 5.02 .

Preservation and Disclosure of Lists

Article 6

Defaults And Remedies

Section 6.01 .

Events of Default

Section 6.02 .

Acceleration; Rescission and Annulment

Section 6.03 .

Special Interest

Section 6.04 .

Payments of Notes on Default; Suit Therefor

Section 6.05 .

Application of Monies Collected by Trustee

Section 6.06 .

Proceedings by Holders

Section 6.07 .

Proceedings by Trustee

Section 6.08 .

Remedies Cumulative and Continuing

Section 6.09 .

Direction of Proceedings and Waiver of Defaults

by Majority of Holders

Section 6.10 .

Notice of Defaults

Section 6.11 .

Undertaking to Pay Costs

Article 7

Concerning The Trustee

Section 7.01 .

Duties and Responsibilities of Trustee

Section 7.02 .

Reliance on Documents, Opinions, Etc

Section 7.03 .

No Responsibility for Recitals, Etc

Section 7.04 .

Trustee, Paying Agents, Conversion Agents, Bid Solicitation

Agent or Note Registrar May Own Notes

Section 7.05 .

Monies and Shares of Common Stock to Be Held in

Trust

Section 7.06 .

Compensation and Expenses of Trustee

Section 7.07 .

Officers’ Certificate as Evidence

Section 7.08 .

Eligibility of Trustee

Section 7.09 .

Resignation or Removal of Trustee

Section 7.10 .

Acceptance by Successor Trustee

Section 7.11 .

Succession by Merger, Etc

Section 7.12 .

Trustee’s Application for Instructions from

the Company

Article 8

Concerning The Holders

Section 8.01 .

Action by Holders

Section 8.02 .

Proof of Execution by Holders

Section 8.03 .

Who Are Deemed Absolute Owners

Section 8.04 .

Company-Owned Notes Disregarded

Section 8.05 .

Revocation of Consents; Future Holders Bound

Article 9

Holders’ Meetings

Section 9.01 .

Purpose of Meetings

Section 9.02 .

Call of Meetings by Trustee

Section 9.03 .

Call of Meetings by Company or Holders

Section 9.04 .

Qualifications for Voting

Section 9.05 .

Regulations

Section 9.06 .

Voting

Section 9.07 .

No Delay of Rights by Meeting

Article 10

Supplemental Indentures

Section 10.01 .

Supplemental Indentures Without Consent of Holders

Section 10.02 .

Supplemental Indentures with Consent of Holders

Section 10.03 .

Effect of Supplemental Indentures

Section 10.04 .

Notation on Notes

Section 10.05 .

Evidence of Compliance of Supplemental Indenture

to Be Furnished Trustee

Article 11

Consolidation, Merger, Sale, Conveyance And Lease

Section 11.01 .

Company May Consolidate, Etc. on Certain Terms

Section 11.02 .

Successor Corporation to Be Substituted

Section 11.03 .

Officers’ Certificate and Opinion of Counsel

to Be Given to Trustee

Article 12

Immunity Of Incorporators, Stockholders, Officers And Directors

Section 12.01 .

Indenture and Notes Solely Corporate Obligations

Article 13

[Intentionally Omitted]

iii

Article 14

Conversion Of Notes

Section 14.01 .

Conversion Privilege

Section 14.02 .

Conversion Procedure; Settlement Upon Conversion

Section 14.03 .

Increased Conversion Rate Applicable to Certain

Notes Surrendered in Connection with Make-Whole Fundamental Changes or a Redemption Notice

Section 14.04 .

Adjustment of Conversion Rate

Section 14.05 .

Adjustments of Prices

Section 14.06 .

Shares to Be Fully Paid

Section 14.07 .

Effect of Recapitalizations, Reclassifications and

Changes of the Common Stock

Section 14.08 .

Certain Covenants

Section 14.09 .

Responsibility of Trustee

Section 14.10 .

[Reserved].

Section 14.11 .

Stockholder Rights Plans

Section 14.12 .

Exchange In Lieu Of Conversion

Article 15

Repurchase Of Notes At Option Of Holders

Section 15.01 .

[Intentionally Omitted]

Section 15.02 .

Repurchase at Option of Holders Upon a Fundamental

Change

Section 15.03 .

Withdrawal of Fundamental Change Repurchase Notice

Section 15.04 .

Deposit of Fundamental Change Repurchase Price

Section 15.05 .

Covenant to Comply with Applicable Laws Upon Repurchase

of Notes

Article 16

Optional Redemption

Section 16.01 .

Optional Redemption

Section 16.02 .

Notice of Optional Redemption; Selection of Notes

Section 16.03 .

Payment of Notes Called for Redemption

Section 16.04 .

Restrictions on Redemption

Article 17

Miscellaneous Provisions

Section 17.01 .

Provisions Binding on Company’s Successors

Section 17.02 .

Official Acts by Successor Corporation

Section 17.03 .

Addresses for Notices, Etc

Section 17.04 .

Governing Law; Jurisdiction

Section 17.05 .

Evidence of Compliance with Conditions Precedent;

Certificates and Opinions of Counsel to Trustee

Section 17.06 .

Legal Holidays

Section 17.07 .

No Security Interest Created

Section 17.08 .

Benefits of Indenture

Section 17.09 .

Table of Contents, Headings, Etc

Section 17.10 .

Authenticating Agent

Section 17.11 .

Execution in Counterparts

101

Section 17.12 .

Severability

101

Section 17.13 .

Waiver of Jury Trial

101

Section 17.14 .

Force Majeure

101

Section 17.15 .

Calculations.

102

Section 17.16 .

USA PATRIOT Act

102

EXHIBIT

Exhibit A

Form of Note

A-1

INDENTURE dated as of June 18, 2026 between

PTC Therapeutics, Inc., a Delaware corporation, as issuer (the “Company,” as more fully set forth in ‎Section 1.01)

and U.S. Bank Trust Company, National Association, a national banking association organized under the laws of the United States, as trustee

(the “Trustee,” as more fully set forth in ‎Section 1.01).

W I T N E S S E T H:

WHEREAS, for its lawful corporate purposes, the

Company has duly authorized the issuance of its 0% Convertible Senior Notes due 2031 (the “Notes”), initially in an

aggregate principal amount not to exceed $550,000,000, and in order to provide the terms and conditions upon which the Notes are to be

authenticated, issued and delivered, the Company has duly authorized the execution and delivery of this Indenture; and

WHEREAS, the Form of Note, the certificate

of authentication to be borne by each Note, the Form of Notice of Conversion, the Form of Fundamental Change Repurchase Notice

and the Form of Assignment and Transfer to be borne by the Notes are to be substantially in the forms hereinafter provided; and

WHEREAS, all acts and things necessary to make

the Notes, when executed by the Company and authenticated and delivered by the Trustee or a duly authorized authenticating agent, as

in this Indenture provided, the valid, binding and legal obligations of the Company, and this Indenture a valid agreement according to

its terms, have been done and performed, and the execution of this Indenture and the issuance hereunder of the Notes have in all respects

been duly authorized.

NOW, THEREFORE, THIS INDENTURE WITNESSETH:

That in order to declare the terms and conditions

upon which the Notes are, and are to be, authenticated, issued and delivered, and in consideration of the premises and of the purchase

and acceptance of the Notes by the Holders thereof, the Company covenants and agrees with the Trustee for the equal and proportionate

benefit of the respective Holders from time to time of the Notes (except as otherwise provided below), as follows:

Article 1

Definitions

Section 1.01.

Definitions. The terms defined in this ‎Section 1.01 (except as herein otherwise expressly provided or unless the context

otherwise requires) for all purposes of this Indenture and of any indenture supplemental hereto shall have the respective meanings specified

in this ‎Section 1.01. The words “herein,” “hereof,” “hereunder” and words of similar import

refer to this Indenture as a whole and not to any particular Article, Section or other subdivision. The terms defined in this Article include

the plural as well as the singular.

“Additional Shares” shall have

the meaning specified in ‎Section 14.03(a).

“Affiliate” of any specified

Person means any other Person directly or indirectly controlling or controlled by or under direct or indirect common control with such

specified Person. For the purposes of this definition, “control,” when used with respect to any specified Person means the

power to direct or cause the direction of the management and policies of such Person, directly or indirectly, whether through the ownership

of voting securities, by contract or otherwise; and the terms “controlling” and “controlled” have meanings correlative

to the foregoing. Notwithstanding anything to the contrary herein, the determination of whether one Person is an “Affiliate”

of another Person for purposes of this Indenture shall be made based on the facts at the time such determination is made or required

to be made, as the case may be, hereunder.

“Bid Solicitation Agent” means

the Company or the Person appointed by the Company to solicit bids for the Trading Price of the Notes in accordance with ‎Section 14.01(b)(i).

The Company shall initially act as the Bid Solicitation Agent. The Company may appoint another Person, including itself, to act as Bid

Solicitation Agent at any time without prior notice to Holders.

“Board of Directors” means

the board of directors of the Company or a committee of such board duly authorized to act for it hereunder.

“Board Resolution” means a

copy of a resolution certified by the Secretary or an Assistant Secretary of the Company to have been duly adopted by the Board of Directors,

and to be in full force and effect on the date of such certification, and delivered to the Trustee.

“Business Day” means, with

respect to any Note, any day other than a Saturday, a Sunday or a day on which the Federal Reserve Bank of New York is authorized or

required by law or executive order to close or be closed.

“Capital Stock” means, for

any entity, any and all shares, interests, rights to purchase, warrants, options, participations or other equivalents of or interests

in (however designated) stock issued by that entity; provided that debt securities that are convertible into or exchangeable for

Capital Stock shall not constitute Capital Stock prior to their conversion or exchange.

“Cash Settlement” shall have

the meaning specified in ‎Section 14.02(a).

“Clause A Distribution” shall

have the meaning specified in ‎Section 14.04(c).

“Clause B Distribution” shall

have the meaning specified in ‎Section 14.04(c).

“Clause C Distribution” shall

have the meaning specified in ‎Section 14.04(c).

“close of business” means 5:00

p.m. (New York City time).

“Combination Settlement” shall

have the meaning specified in ‎Section 14.02(a).

“Commission” means the U.S.

Securities and Exchange Commission.

“Common Equity” of any Person

means Capital Stock of such Person that is generally entitled (a) to vote in the election of directors of such Person or (b) if

such Person is not a corporation, to vote or otherwise participate in the selection of the governing body, partners, managers or others

that will control the management or policies of such Person.

“Common Stock” means the common

stock of the Company, par value $0.001 per share, at the date of this Indenture, subject to ‎Section 14.07.

“Company” shall have the meaning

specified in the first paragraph of this Indenture, and subject to the provisions of ‎Article 11, shall include its successors

and assigns.

“Company Order” means a written

order of the Company, signed by (a) the Company’s Chief Executive Officer, President, Chief Financial Officer, Executive

or Senior Vice President or any Vice President (whether or not designated by a number or numbers or word or words added before or after

the title “Vice President”) and (b) any such other Officer designated in clause (a) of this definition or the

Company’s Treasurer or Assistant Treasurer or Secretary or any Assistant Secretary, and delivered to the Trustee.

“Conversion Agent” shall have

the meaning specified in ‎Section 4.02.

“Conversion Consideration”

shall have the meaning specified in ‎Section 14.12(a).

“Conversion Date” shall have

the meaning specified in ‎Section 14.02(c).

“Conversion Obligation” shall

have the meaning specified in ‎Section 14.01(a).

“Conversion Price” means as

of any time, $1,000, divided by the Conversion Rate as of such time.

“Conversion Rate” shall have

the meaning specified in ‎Section 14.01(a).

“Corporate Event” shall have

the meaning specified in ‎Section 14.01(b)(iii).

“Corporate Trust Office” means

the designated office of the Trustee at which at any time this Indenture shall be administered, which office at the date hereof is located

at CityPlace I, 185 Asylum Street, 27th Floor, Hartford, CT 06103, Attn: L. Casasanta, or such other address as the Trustee

may designate from time to time by notice to the Holders and the Company, or the designated corporate trust office of any successor trustee

(or such other address as such successor trustee may designate from time to time by notice to the Holders and the Company).

“Custodian” means the Trustee,

as custodian for The Depository Trust Company, with respect to the Global Notes, or any successor entity thereto.

“Daily Conversion Value” means,

for each of the 25 consecutive Trading Days during the Observation Period, 4.00% of the product of (a) the Conversion Rate on such

Trading Day and (b) the Daily VWAP for such Trading Day.

“Daily Measurement Value” means

the Specified Dollar Amount (if any), divided by 25.

“Daily Settlement Amount,”

for each of the 25 consecutive Trading Days during the Observation Period, shall consist of:

(a)            cash

in an amount equal to the lesser of (i) the Daily Measurement Value and (ii) the Daily Conversion Value on such Trading Day;

and

(b)            if

the Daily Conversion Value on such Trading Day exceeds the Daily Measurement Value, a number of shares of Common Stock equal to (i) the

difference between the Daily Conversion Value and the Daily Measurement Value, divided by (ii) the Daily VWAP for such Trading

Day.

“Daily VWAP” means, for each

of the 25 consecutive Trading Days during the relevant Observation Period, the per share volume-weighted average price as displayed under

the heading “Bloomberg VWAP” on Bloomberg page “PTCT<equity> AQR” (or its equivalent successor if

such page is not available) in respect of the period from the scheduled open of trading until the scheduled close of trading of

the primary trading session on such Trading Day (or if such volume-weighted average price is unavailable, the market value of one share

of the Common Stock on such Trading Day determined, using a volume-weighted average method, by a nationally recognized independent investment

banking firm retained for this purpose by the Company). The “Daily VWAP” shall be determined without regard to after-hours

trading or any other trading outside of the regular trading session trading hours.

“Default” means any event that

is, or after notice or passage of time, or both, would be, an Event of Default.

“Defaulted Amounts” means any

amounts on any Note (including, without limitation, the Redemption Price, the Fundamental Change Repurchase Price, principal and Special

Interest, if any) that are payable but are not punctually paid or duly provided for.

“Deferred Special Interest”

shall have the meaning specified in ‎Section 4.06(f).

“Deferred Special Interest Demand Request”

shall have the meaning specified in ‎Section 4.06(f).

“delivered”

with respect to any notice to be delivered, given or mailed to a Holder pursuant to this Indenture, shall mean notice (x) in the

case of a Global Note, given to the Depositary (or its designee) pursuant to the standing instructions from the Depositary or its designee,

including by electronic mail in accordance with accepted practices or procedures at the Depositary or (y) in the case of a Physical

Note, mailed to such Holder by first class mail, postage prepaid, at its address as it appears on the Note Register, in each case in

accordance with ‎‎Section 17.03. Notice so “delivered” shall be deemed to include any notice to be “mailed”

or “given,” as applicable, under this Indenture.

“Depositary” means, with respect

to each Global Note, the Person specified in ‎Section 2.05(c) as the Depositary with respect to such Notes, until a successor

shall have been appointed and become such pursuant to the applicable provisions of this Indenture, and thereafter, “Depositary”

shall mean or include such successor.

“Designated Financial Institution”

shall have the meaning specified in ‎Section 14.12(a).

“Distributed Property” shall

have the meaning specified in ‎Section 14.04(c).

“Distribution Trigger Irrevocable Physical

Settlement Period” shall have the meaning specified in ‎Section 14.01(b)(ii).

“Effective Date” shall have

the meaning specified in ‎Section 14.03(c), except that, as used in ‎Section 14.04 and ‎Section 14.05,

“Effective Date” means the first date on which shares of the Common Stock trade on the applicable exchange or in the

applicable market, regular way, reflecting the relevant share split or share combination, as applicable (provided that any alternative

trading convention on the applicable exchange or market in respect of shares of Common Stock under a separate ticker symbol or CUSIP

number shall not be considered “regular way” for this purpose).

“Event of Default” shall have

the meaning specified in ‎Section 6.01.

“Ex-Dividend Date” means the

first date on which shares of the Common Stock trade on the applicable exchange or in the applicable market, regular way, without the

right to receive the issuance, dividend or distribution in question, from the Company or, if applicable, from the seller of Common Stock

on such exchange or market (in the form of due bills or otherwise) as determined by such exchange or market (provided that any

alternative trading convention on the applicable exchange or market in respect of shares of Common Stock under a separate ticker symbol

or CUSIP number shall not be considered “regular way” for this purpose).

“Exchange Act” means the Securities

Exchange Act of 1934, as amended, and the rules and regulations promulgated thereunder.

“Exchange Election” shall have

the meaning specified in ‎Section 14.12(a).

“Form of Assignment and Transfer”

means the “Form of Assignment and Transfer” attached as Attachment 3 to the Form of Note attached hereto as Exhibit A.

“Form of Fundamental Change Repurchase

Notice” means the “Form of Fundamental Change Repurchase Notice” attached as Attachment 2 to the Form of

Note attached hereto as Exhibit A.

“Form of Note” means

the “Form of Note” attached hereto as Exhibit A.

“Form of Notice of Conversion”

means the “Form of Notice of Conversion” attached as Attachment 1 to the Form of Note attached hereto as Exhibit A.

“Freely Tradable” means, with

respect to any Note, that such Note would be eligible to be offered, sold or otherwise transferred pursuant to Rule 144 or otherwise

if held by a Person that is not an affiliate (within the meaning of Rule 144) of the Company, and that has not been an affiliate

(within the meaning of Rule 144) of the Company during the immediately preceding three months, without any requirements as to volume,

manner of sale, availability of current public information or notice under the Securities Act (except that, during the six-month period

beginning on, and including, the date that is six months after the last date of original issuance of such Note, any such requirement

as to the availability of current public information shall be disregarded if the same is satisfied at that time).

“Fundamental Change” shall

be deemed to have occurred at the time after the Notes are originally issued and prior to the Maturity Date if any of the following occurs

prior to the Maturity Date:

(a)            a

“person” or “group” within the meaning of Section 13(d) of the Exchange Act, other than the Company,

its direct or indirect Wholly Owned Subsidiaries and the employee benefit plans of the Company and its direct or indirect Wholly Owned

Subsidiaries, files a Schedule TO or any schedule, form or report under the Exchange Act that discloses that such “person”

or “group” has become the direct or indirect “beneficial owner,” as defined in Rule 13d-3 under the Exchange

Act, of the Common Stock representing more than 50% of the voting power of the Common Stock (provided that no “person”

or “group” shall be deemed to be the beneficial owner of any securities tendered pursuant to a tender offer or exchange offer

made by or on behalf of such “person” or “group” until such tendered securities are accepted for purchase or

exchange under such offer);

(b)            the

consummation of (A) any recapitalization, reclassification or change of the Common Stock (other than changes resulting from a subdivision,

combination or change in par value) as a result of which the Common Stock would be converted into, or exchanged for, stock, other securities,

other property or assets; (B) any share exchange, consolidation or merger of the Company pursuant to which the Common Stock will

be converted into cash, securities or other property or assets; or (C) any sale, lease or other transfer in one transaction or

a series of transactions of all or substantially all of the consolidated assets of the Company and its Subsidiaries, taken as a whole,

to any Person other than one or more of the Company’s Wholly Owned Subsidiaries; provided, however, that a transaction described

in clause (A) or (B) in which the holders of all classes of the Company’s Common Equity immediately prior to such transaction

own, directly or indirectly, more than 50% of all classes of Common Equity of the continuing or surviving corporation or transferee or

the parent thereof immediately after such transaction in substantially the same proportions (relative to each other) as such ownership

immediately prior to such transaction shall not be a Fundamental Change pursuant to this clause (b);

stockholders of the Company approve any plan or proposal for the liquidation or dissolution of the Company; or

(d)            the

Common Stock (or other common stock underlying the Notes) ceases to be listed or quoted on any of The New York Stock Exchange, The Nasdaq

Global Select Market or The Nasdaq Global Market (or any of their respective successors);

provided, however,

that a transaction or transactions described in clause (a) or clause (b) above shall not constitute a Fundamental Change,

if at least 90% of the consideration received or to be received by the common stockholders of the Company, excluding cash payments for

fractional shares or pursuant to statutory appraisal rights, in connection with such transaction or transactions consists of shares of

common stock or a class of common stock that are listed or quoted on any of The New York Stock Exchange, The Nasdaq Global Select Market

or The Nasdaq Global Market (or any of their respective successors) or will be so listed or quoted when issued or exchanged in connection

with such transaction or transactions and as a result of such transaction or transactions the Notes become convertible into such consideration,

excluding cash payments for fractional shares or pursuant to statutory appraisal rights (subject to the provisions of ‎Section 14.02(a)).

Solely for purposes of this definition (and, for the avoidance of doubt, not for purposes of the “Make-Whole Fundamental Change”

definition), any transaction that constitutes a Fundamental Change pursuant to both clause (a) and clause (b) of this definition

(without giving effect to the proviso in clause (b)) shall be deemed a Fundamental Change solely under clause (b) of this

definition (subject to the proviso in clause (b)).

If any transaction in which the Common Stock is replaced by the securities

of another entity occurs, following completion of any related Make-Whole Fundamental Change Period (or, in the case of a transaction

that would have been a Fundamental Change or a Make-Whole Fundamental Change but for the proviso immediately following clause (d) of

this definition, following the effective date of such transaction) references to the Company in this definition shall instead be references

to such other entity.

“Fundamental Change Company Notice”

shall have the meaning specified in ‎Section 15.02(c).

“Fundamental Change Repurchase Date”

shall have the meaning specified in ‎Section 15.02(a).

“Fundamental Change Repurchase Notice”

shall have the meaning specified in ‎Section 15.02(b)(i).

“Fundamental Change Repurchase Price”

shall have the meaning specified in ‎Section 15.02(a).

“Global Note” shall have the

meaning specified in ‎Section 2.05(b).

“Holder,” as applied to any

Note, or other similar terms (but excluding the term “beneficial holder”), means any Person in whose name at the time a particular

Note is registered on the Note Register.

“Indenture” means this instrument

as originally executed or, if amended or supplemented as herein provided, as so amended or supplemented.

“Last Reported Sale Price”

of the Common Stock (or other security for which a Last Reported Sale Price must be determined) on any date means the closing sale price

per share (or if no closing sale price is reported, the average of the bid and ask prices or, if more than one in either case, the average

of the average bid and the average ask prices) on that date as reported in composite transactions for the principal U.S. national or

regional securities exchange on which the Common Stock (or such other security) is traded. If the Common Stock (or such other security)

is not listed for trading on a U.S. national or regional securities exchange on the relevant date, the “Last Reported Sale Price”

shall be the last quoted bid price for the Common Stock (or such other security) in the over-the-counter market on the relevant date

as reported by OTC Markets Group Inc. or a similar organization. If the Common Stock (or such other security) is not so quoted, the “Last

Reported Sale Price” shall be the average of the mid-point of the last bid and ask prices for the Common Stock (or such other

security) on the relevant date from each of at least three nationally recognized independent investment banking firms selected by the

Company for this purpose. The “Last Reported Sale Price” shall be determined without regard to after-hours trading

or any other trading outside of the regular trading session hours.

“Make-Whole Fundamental Change”

means any transaction or event that constitutes a Fundamental Change (as defined above and determined after giving effect to any exceptions

to or exclusions from such definition, but without regard to the proviso in clause (b) of the definition thereof).

“Make-Whole Fundamental Change Period”

shall have the meaning specified in ‎Section 14.03(a).

“Market Disruption Event” means,

for the purposes of determining amounts due upon conversion (a) a failure by the primary U.S. national or regional securities exchange

or market on which the Common Stock is listed or admitted for trading to open for trading during its regular trading session or (b) the

occurrence or existence prior to 1:00 p.m., New York City time, on any Scheduled Trading Day for the Common Stock for more than one half-hour

period in the aggregate during regular trading hours of any suspension or limitation imposed on trading (by reason of movements in price

exceeding limits permitted by the relevant stock exchange or otherwise) in the Common Stock or in any options contracts or futures contracts

relating to the Common Stock.

“Maturity Date” means June 15,

2031.

“Measurement Period” shall

have the meaning specified in ‎Section 14.01(b)(i).

“Note” or “Notes”

shall have the meaning specified in the first paragraph of the recitals of this Indenture.

“Note Register” shall have

the meaning specified in ‎Section 2.05(a).

“Note Registrar” shall have

the meaning specified in ‎Section 2.05(a).

“Notice of Conversion” shall

have the meaning specified in ‎Section 14.02(b).

“Notice of Election to Pay Deferred Special

Interest” shall have the meaning specified in ‎Section 4.06(f).

“Observation Period” with respect

to any Note surrendered for conversion means: (i) subject to clause (ii), if the relevant Conversion Date occurs prior to March 15,

2031, the 25 consecutive Trading Day period beginning on, and including, the second Trading Day immediately succeeding such Conversion

Date; (ii) if the relevant Conversion Date occurs on or after the date of the Company’s issuance of a Redemption Notice with

respect to the Notes pursuant to ‎Section 16.02 and prior to the close of business on the second Scheduled Trading Day immediately

preceding the relevant Redemption Date, the 25 consecutive Trading Days beginning on, and including, the 26th Scheduled Trading Day immediately

preceding such Redemption Date; and (iii) subject to clause (ii), if the relevant Conversion Date occurs on or after March 15,

2031, the 25 consecutive Trading Days beginning on, and including, the 26th Scheduled Trading Day immediately preceding the Maturity

Date.

“Offering Memorandum” means

the preliminary offering memorandum dated June 15, 2026, as supplemented by the related pricing term sheet dated June 15,

2026, relating to the offering and sale of the Notes.

“Officer” means, with respect

to the Company, the President, the Chief Executive Officer, the Chief Financial Officer, the Treasurer, the Secretary, any Executive

or Senior Vice President or any Vice President (whether or not designated by a number or numbers or word or words added before or after

the title “Vice President”).

“Officers’ Certificate,”

when used with respect to the Company, means a certificate that is delivered to the Trustee and that is signed by (a) two Officers

of the Company or (b) one Officer of the Company and one of any Assistant Treasurer, the Secretary, any Assistant Secretary or

the Controller of the Company. Each such certificate shall include the statements provided for in ‎Section 17.05 if and to

the extent required by the provisions of such Section. One of the Officers giving an Officers’ Certificate pursuant to ‎Section 4.08

shall be the principal executive, financial or accounting officer of the Company.

“open of business” means 9:00

a.m. (New York City time).

“Opinion of Counsel” means

an opinion in writing signed by legal counsel, who may be an employee of or counsel to the Company, or other counsel reasonably acceptable

to the Trustee, which opinion may contain customary exceptions and qualifications as to the matters set forth therein, that is delivered

to the Trustee. Each such opinion shall include the statements provided for in ‎Section 17.05 if and to the extent required

by the provisions of such ‎Section 17.05.

“Optional Redemption” shall

have the meaning specified in ‎Section 16.01.

“outstanding,” when used with

reference to Notes, shall, subject to the provisions of ‎Section 8.04, mean, as of any particular time, all Notes authenticated

and delivered by the Trustee under this Indenture, except:

(a)            Notes

theretofore canceled by the Trustee or accepted by the Trustee for cancellation;

(b)            Notes,

or portions thereof, that have become due and payable and in respect of which monies in the necessary amount shall have been deposited

in trust with the Trustee or with any Paying Agent (other than the Company) or shall have been set aside and segregated in trust by the

Company (if the Company shall act as its own Paying Agent);

that have been paid pursuant to ‎Section 2.06 or Notes in lieu of which, or in substitution for which, other Notes shall have

been authenticated and delivered pursuant to the terms of ‎Section 2.06 unless proof satisfactory to the Trustee is presented

that any such Notes are held by protected purchasers in due course;

(d)            Notes

converted pursuant to ‎Article 14 and required to be cancelled pursuant to ‎Section 2.08;

(e)            Notes

redeemed pursuant to ‎Article 16; and

(f)            Notes

repurchased by the Company pursuant to Article 15 and ‎Section 2.10 and, in each case, delivered to the Trustee for cancellation.

“Paying Agent” shall have the

meaning specified in ‎Section 4.02.

“Person” means an individual,

a corporation, a limited liability company, an association, a partnership, a joint venture, a joint stock company, a trust, an unincorporated

organization or a government or an agency or a political subdivision thereof.

“Physical Notes” means permanent

certificated Notes in registered form issued in minimum denominations of $1,000 principal amount and integral multiples in excess thereof.

“Physical Settlement” shall

have the meaning specified in ‎Section 14.02(a).

“Predecessor Note” of any particular

Note means every previous Note evidencing all or a portion of the same debt as that evidenced by such particular Note; and, for the purposes

of this definition, any Note authenticated and delivered under ‎Section 2.06 in lieu of or in exchange for a mutilated, lost,

destroyed or stolen Note shall be deemed to evidence the same debt as the mutilated, lost, destroyed or stolen Note that it replaces.

“Record Date” means, with respect

to any dividend, distribution or other transaction or event in which the holders of Common Stock (or other applicable security) have

the right to receive any cash, securities or other property or in which the Common Stock (or such other security) is exchanged for or

converted into any combination of cash, securities or other property, the date fixed for determination of holders of the Common Stock

(or such other security) entitled to receive such cash, securities or other property (whether such date is fixed by the Board of Directors,

by statute, by contract or otherwise).

“Redemption Date” shall have

the meaning specified in ‎Section 16.02(a).

“Redemption Notice” shall have

the meaning specified in ‎Section 16.02(a).

“Redemption Price” means, for

any Notes to be redeemed pursuant to ‎Section 16.01, 100% of the principal amount of such Notes, plus accrued and unpaid

Special Interest, if any, to, but excluding, the Redemption Date (unless the Redemption Date falls after a Special Interest Record Date

but on or prior to the immediately succeeding Special Interest Payment Date, in which case any Special Interest accrued to the Special

Interest Payment Date will be paid to Holders of record of such Notes as of the close of business on such Special Interest Record Date,

and the Redemption Price will be equal to 100% of the principal amount of such Notes).

“Reference Property” shall

have the meaning specified in ‎Section 14.07(a).

“Resale Restriction Termination Date”

shall have the meaning specified in ‎Section 2.05(c).

“Responsible Officer” means,

when used with respect to the Trustee, any officer within the corporate trust office of the Trustee, including any vice president, assistant

vice president, assistant secretary, assistant treasurer, trust officer or any other officer of the Trustee who customarily performs

functions similar to those performed by the Persons who at the time shall be such officers who shall have direct responsibility for the

administration of this Indenture respectively, or any other officer of such Trustee to whom any corporate trust matter relating to this

Indenture is referred because of such person's knowledge of and familiarity with the particular subject.

“Restricted Securities” shall

have the meaning specified in ‎Section 2.05(c).

“Rule 144” means Rule 144

as promulgated under the Securities Act.

“Rule 144A” means Rule 144A

as promulgated under the Securities Act.

“Scheduled Trading Day” means

a day that is scheduled to be a Trading Day on the principal U.S. national or regional securities exchange or market on which the Common

Stock is listed or admitted for trading. If the Common Stock is not so listed or admitted for trading, “Scheduled Trading Day”

means a Business Day.

“Securities Act” means the

Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder.

“Settlement Amount” shall have

the meaning specified in ‎Section 14.02(a)(iv).

“Settlement Method” means,

with respect to any conversion of Notes, Physical Settlement, Cash Settlement or Combination Settlement, as elected (or deemed to have

been elected) by the Company.

“Settlement Notice” shall have

the meaning specified in ‎Section 14.02(a)(iii).

“Share Exchange Event” shall

have the meaning specified in ‎Section 14.07(a).

“Signature Law” shall have

the meaning specified in ‎Section 17.11.

“Significant Subsidiary” means

a Subsidiary of the Company that meets the definition of “significant subsidiary” in Article 1, Rule 1-02(w) of

Regulation S-X promulgated by the Commission (or any successor rule).

“Special Interest” means all

amounts, if any, payable pursuant to ‎Section 4.06(d), ‎Section 4.06(e) and ‎Section 6.03, as applicable.

“Special Interest Payment Date”

means, if and to the extent that Special Interest is payable on the Notes, each June 15 and December 15 of each year, beginning

on December 15, 2026 (if any Special Interest is then payable).

“Special Interest Record Date,”

with respect to any Special Interest Payment Date, means the June 1 and December 1 (whether or not such day is a Business

Day) immediately preceding the applicable June 15 and December 15 Special Interest Payment Date, respectively.

“Specified Dollar Amount” means

the maximum cash amount (excluding cash in lieu of any fractional share of Common Stock) per $1,000 principal amount of Notes to be received

upon conversion as specified in the Settlement Notice related to any converted Notes (or deemed specified as set forth in ‎Section 14.02(a)(iii)).

“Spin-Off” shall have the meaning

specified in ‎Section 14.04(c).

“Stock Price” shall have the

meaning specified in ‎Section 14.03(c).

“Subsidiary” means, with respect

to any Person, any corporation, association, partnership or other business entity of which more than 50% of the total voting power of

shares of Capital Stock or other interests (including partnership interests) entitled (without regard to the occurrence of any contingency)

to vote in the election of directors, managers, general partners or trustees thereof is at the time owned or controlled, directly or

indirectly, by (i) such Person; (ii) such Person and one or more Subsidiaries of such Person; or (iii) one or more

Subsidiaries of such Person.

“Successor Company” shall have

the meaning specified in ‎Section 11.01(a).

“Tender Agent” shall have the

meaning specified in ‎Section 15.02(b)(i).

“Trading Day” means, except

for purposes of determining the amount of cash and/or the number of shares of Common Stock due upon conversion, a day on which (i) trading

in the Common Stock (or other security for which a closing sale price must be determined) generally occurs on The Nasdaq Global Select

Market or, if the Common Stock (or such other security) is not then listed on The Nasdaq Global Select Market, on the principal other

U.S. national or regional securities exchange on which the Common Stock (or such other security) is then listed or, if the Common Stock

(or such other security) is not then listed on a U.S. national or regional securities exchange, on the principal other market on which

the Common Stock (or such other security) is then traded and (ii) a Last Reported Sale Price for the Common Stock (or closing sale

price for such other security) is available on such securities exchange or market; provided that if the Common Stock (or such

other security) is not so listed or traded, “Trading Day” means a Business Day; and provided, further,

that for purposes of determining the amount of cash and/or the number of shares of the Common Stock due upon conversion only, “Trading

Day” means a day on which (x) there is no Market Disruption Event and (y) trading in the Common Stock generally

occurs on The Nasdaq Global Select Market or, if the Common Stock is not then listed on The Nasdaq Global Select Market, on the principal

other U.S. national or regional securities exchange on which the Common Stock is then listed or, if the Common Stock is not then listed

on a U.S. national or regional securities exchange, on the principal other market on which the Common Stock is then listed or admitted

for trading, except that if the Common Stock is not so listed or admitted for trading, “Trading Day” means a Business

Day.

“Trading Price” of the Notes

on any date of determination means the average of the secondary market bid quotations obtained by the Bid Solicitation Agent for $5,000,000

principal amount of Notes at approximately 3:30 p.m., New York City time, on such determination date from three independent nationally

recognized securities dealers the Company selects for this purpose; provided that if three such bids cannot reasonably be obtained

by the Bid Solicitation Agent but two such bids are obtained, then the average of the two bids shall be used, and if only one such bid

can reasonably be obtained by the Bid Solicitation Agent, that one bid shall be used. If, on any Trading Day, the Bid Solicitation Agent

cannot reasonably obtain at least one bid for $5,000,000 principal amount of Notes on such date from a nationally recognized securities

dealer on any determination date, then the Trading Price per $1,000 principal amount of Notes on such determination date shall be deemed

to be less than 98% of the product of the Last Reported Sale Price of the Common Stock and the Conversion Rate.

“transfer” shall have the meaning

specified in ‎Section 2.05(c).

“Trigger Event” shall have

the meaning specified in ‎Section 14.04(c).

“Trust Indenture Act” means

the Trust Indenture Act of 1939, as amended, as it was in force at the date of execution of this Indenture; provided, however,

that in the event the Trust Indenture Act of 1939 is amended after the date hereof, the term “Trust Indenture Act” shall

mean, to the extent required by such amendment, the Trust Indenture Act of 1939, as so amended.

“Trustee” means the Person

named as the “Trustee” in the first paragraph of this Indenture until a successor trustee shall have become such pursuant

to the applicable provisions of this Indenture, and thereafter “Trustee” shall mean or include each Person who is

then a Trustee hereunder.

“unit of Reference Property”

shall have the meaning specified in ‎Section 14.07(a).

“Valuation Period” shall have

the meaning specified in ‎Section 14.04(c).

“Wholly Owned Subsidiary” means,

with respect to any Person, any Subsidiary of such Person, except that, solely for purposes of this definition, the reference to “more

than 50%” in the definition of “Subsidiary” shall be deemed replaced by a reference to “100%”.

Section 1.02. References to Interest.

Unless the context otherwise requires, any reference to interest or Special Interest on, or in respect of, any Note in this Indenture

shall be deemed to refer solely to Special Interest (including any Deferred Special Interest and, if applicable, any interest thereon)

if, in such context, Special Interest (including any Deferred Special Interest and, if applicable, any interest thereon) is, was or would

be payable pursuant to any of ‎Section 4.06(d), ‎Section 4.06(e) and ‎Section 6.03, and/or to any

interest payable on any Defaulted Amounts as set forth in ‎‎Section 2.03(c). Unless the context otherwise requires, any

express mention of Special Interest, Deferred Special Interest and/or interest thereon in any provision hereof shall not be construed

as excluding Special Interest, Deferred Special Interest and/or interest thereon in those provisions hereof where such express mention

is not made.

Article 2

Issue, Description, Execution, Registration and Exchange of Notes

Section 2.01. Designation and Amount.

The Notes shall be designated as the “0% Convertible Senior Notes due 2031.” The aggregate principal amount of Notes that

may be authenticated and delivered under this Indenture is initially limited to $550,000,000, subject to ‎Section 2.10 and

except for Notes authenticated and delivered upon registration or transfer of, or in exchange for, or in lieu of other Notes to the extent

expressly permitted hereunder.

Section 2.02. Form of Notes.

The Notes and the Trustee’s certificate of authentication to be borne by such Notes shall be substantially in the respective forms

set forth in Exhibit A, the terms and provisions of which shall constitute, and are hereby expressly incorporated in and made a

part of this Indenture. To the extent applicable, the Company and the Trustee, by their execution and delivery of this Indenture, expressly

agree to such terms and provisions and to be bound thereby. In the case of any conflict between this Indenture and a Note, the provisions

of this Indenture shall control and govern to the extent of such conflict.

The Notes shall be issued initially in the form

of one or more Global Notes. Any Global Note may be endorsed with or have incorporated in the text thereof such legends or recitals or

changes not inconsistent with the provisions of this Indenture as may be required by the Custodian or the Depositary, or as may be required

to comply with any applicable law or any regulation thereunder or with the rules and regulations of any securities exchange or

automated quotation system upon which the Notes may be listed or traded or designated for issuance or to conform with any usage with

respect thereto, or to indicate any special limitations or restrictions to which any particular Notes are subject.

Any of the Notes may have such letters, numbers

or other marks of identification and such notations, legends or endorsements as the Officer executing the same may approve (execution

thereof to be conclusive evidence of such approval) and as are not inconsistent with the provisions of this Indenture, or as may be required

to comply with any law or with any rule or regulation made pursuant thereto or with any rule or regulation of any securities

exchange or automated quotation system on which the Notes may be listed or designated for issuance, or to conform to usage or to indicate

any special limitations or restrictions to which any particular Notes are subject.

Each Global Note shall represent such principal

amount of the outstanding Notes as shall be specified therein and shall provide that it shall represent the aggregate principal amount

of outstanding Notes from time to time endorsed thereon and that the aggregate principal amount of outstanding Notes represented thereby

may from time to time be increased or reduced to reflect redemptions, repurchases, cancellations, conversions, transfers or exchanges

permitted hereby. Any endorsement of a Global Note to reflect the amount of any increase or decrease in the amount of outstanding Notes

represented thereby shall be made by the Trustee or the Custodian, at the direction of the Trustee, in such manner and upon instructions

given by the Holder of such Notes in accordance with this Indenture. Payment of principal (including the Redemption Price and the Fundamental

Change Repurchase Price, if applicable) of, and any accrued and unpaid Special Interest on, a Global Note shall be made to the Holder

of such Note on the date of payment, unless a record date or other means of determining Holders eligible to receive payment is provided

for herein.

Section 2.03. Date and Denomination of

Notes; No Regular Interest; Special Interest and Defaulted Amounts. (a) The Notes shall be issuable in registered form without

coupons in minimum denominations of $1,000 principal amount and integral multiples of $1,000 in excess thereof. Each Note shall be dated

the date of its authentication and shall not bear regular interest, and the principal amount of the Notes shall not accrete. Special

Interest on the Notes, if any, shall be computed on the basis of a 360-day year composed of twelve 30-day months and, for partial months,

on the basis of the number of days actually elapsed in a 30-day month.

(b)            The

Person in whose name any Note (or its Predecessor Note) is registered on the Note Register at the close of business on any Special Interest

Record Date with respect to any Special Interest Payment Date shall be entitled to receive the Special Interest payable on such Special

Interest Payment Date. The principal amount of any Note (x) in the case of any Physical Note, shall be payable at the office or

agency of the Company maintained by the Company for such purposes in the United States of America, which shall initially be the Corporate

Trust Office and (y) in the case of any Global Note, shall be payable by wire transfer of immediately available funds to the account

of the Depositary or its nominee. The Company shall pay, or cause the Paying Agent to pay, Special Interest, if any (i) on any

Physical Notes (A) to Holders holding Physical Notes having an aggregate principal amount of $5,000,000 or less, by check mailed

to the Holders of these Notes at their address as it appears in the Note Register and (B) to Holders holding Physical Notes having

an aggregate principal amount of more than $5,000,000, either by check mailed to each Holder or, upon application by such a Holder to

the Paying Agent not later than the relevant Special Interest Record Date, by wire transfer in immediately available funds to that Holder’s

account within the United States if such Holder has provided the Trustee or the Paying Agent (if other than the Trustee) with the requisite

information necessary to make such wire transfer, which application shall remain in effect until the Holder notifies, in writing, the

Paying Agent to the contrary or (ii) on any Global Note by wire transfer of immediately available funds to the account of the Depositary

or its nominee.

Defaulted Amounts shall forthwith cease to be payable to the Holder on the relevant payment date and shall not accrue interest unless

Special Interest was payable pursuant to this Indenture on the relevant payment date, in which case such Defaulted Amounts shall accrue

interest per annum at the then-applicable Special Interest rate borne by the Notes, subject to the enforceability thereof under applicable

law, from, and including, such relevant payment date, and such Defaulted Amounts together with any such interest thereon shall be paid

by the Company, at its election in each case, as provided in clause (i) or (ii) below:

(i)            The

Company may elect to make payment of any Defaulted Amounts to the Persons in whose names the Notes (or their respective Predecessor Notes)

are registered at the close of business on a special record date for the payment of such Defaulted Amounts, which shall be fixed in the

following manner. The Company shall notify the Trustee in writing of the amount of the Defaulted Amounts proposed to be paid on each

Note and the date of the proposed payment (which shall be not less than 25 days after the receipt by the Trustee of such notice, unless

the Trustee shall consent to an earlier date), and at the same time the Company shall deposit with the Trustee an amount of money equal

to the aggregate amount to be paid in respect of such Defaulted Amounts or shall make arrangements satisfactory to the Trustee for such

deposit on or prior to the date of the proposed payment, such money when deposited to be held in trust for the benefit of the Persons

entitled to such Defaulted Amounts as in this clause provided. Thereupon the Company shall fix a special record date for the payment

of such Defaulted Amounts which shall be not more than 15 days and not less than 10 days prior to the date of the proposed payment, and

not less than 10 days after the receipt by the Trustee of the notice of the proposed payment (unless the Trustee shall consent to an

earlier date). The Company shall promptly notify the Trustee in writing of such special record date and the Company, or the Trustee at

the request of and in the name and at the expense of the Company, shall cause notice of the proposed payment of such Defaulted Amounts

and the special record date therefor to be delivered to each Holder not less than 10 days prior to such special record date; provided

that the Trustee has received such notice from the Company at least three Business Days prior to the date such notice is to be sent (or

such shorter period as shall be acceptable to the Trustee). Notice of the proposed payment of such Defaulted Amounts and the special

record date therefor having been so delivered, such Defaulted Amounts shall be paid to the Persons in whose names the Notes (or their

respective Predecessor Notes) are registered at the close of business on such special record date and shall no longer be payable pursuant

to the following clause (ii) of this ‎Section 2.03‎(c). The Trustee shall have no responsibility whatsoever for the

calculation of the Defaulted Amounts.

(ii)            The

Company may make payment of any Defaulted Amounts in any other lawful manner not inconsistent with the requirements of any securities

exchange or automated quotation system on which the Notes may be listed or designated for issuance, and upon such notice as may be required

by such exchange or automated quotation system, if, after notice given by the Company to the Trustee of the proposed payment pursuant

to this clause, such manner of payment shall be deemed practicable by the Trustee. For the avoidance of doubt, the Company may make payment

of any Defaulted Amounts and any interest thereon relating to any amounts due upon conversion of the Notes in a manner other than as

provided in ‎Section 2.03(c)(i) if such manner would be permitted under the terms of this Indenture if such amounts due

upon conversion were not Defaulted Amounts or default interest.

Section 2.04. Execution, Authentication

and Delivery of Notes. The Notes shall be signed in the name and on behalf of the Company by the manual or facsimile or other electronic

signature of its Chief Executive Officer, Chief Operating Officer, Chief Financial Officer or Secretary.

At any time and from time to time after the execution

and delivery of this Indenture, the Company may deliver Notes executed by the Company to the Trustee for authentication, together with

a Company Order for the authentication and delivery of such Notes, and the Trustee in accordance with such Company Order shall authenticate

and deliver such Notes, without any further action by the Company hereunder; provided that, subject to Section 17.05, upon

request of the Trustee, the Trustee shall receive an Officers’ Certificate and an Opinion of Counsel of the Company with respect

to the issuance, authentication and delivery of such Notes.

Only such Notes as shall bear thereon a certificate

of authentication substantially in the form set forth on the Form of Note attached as Exhibit A hereto, executed manually

by an authorized signatory of the Trustee (or an authenticating agent appointed by the Trustee as provided by ‎Section 17.10),

shall be entitled to the benefits of this Indenture or be valid or obligatory for any purpose. Such certificate by the Trustee (or such

an authenticating agent) upon any Note executed by the Company shall be conclusive evidence that the Note so authenticated has been duly

authenticated and delivered hereunder and that the Holder is entitled to the benefits of this Indenture.

In case any Officer of the Company who shall have

signed any of the Notes shall cease to be such Officer before the Notes so signed shall have been authenticated and delivered by the

Trustee, or disposed of by the Company, such Notes nevertheless may be authenticated and delivered or disposed of as though the person

who signed such Notes had not ceased to be such Officer of the Company; and any Note may be signed on behalf of the Company by such persons

as, at the actual date of the execution of such Note, shall be the Officers of the Company, although at the date of the execution of

this Indenture any such person was not such an Officer.

Section 2.05. Exchange and Registration

of Transfer of Notes; Restrictions on Transfer; Depositary. (a) The Company shall cause to be kept at the Corporate Trust Office

a register (the register maintained in such office or in any other office or agency of the Company designated pursuant to ‎Section 4.02,

the “Note Register”) in which, subject to such reasonable regulations as it may prescribe, the Company shall provide

for the registration of Notes and of transfers of Notes. Such register shall be in written form or in any form capable of being converted

into written form within a reasonable period of time. The Trustee is hereby initially appointed the “Note Registrar”

for the purpose of registering Notes and transfers of Notes as herein provided. The Company may appoint one or more co-Note Registrars

in accordance with ‎Section 4.02.

Upon surrender for registration of transfer of

any Note to the Note Registrar or any co-Note Registrar, and satisfaction of the requirements for such transfer set forth in this ‎Section 2.05,

the Company shall execute, and the Trustee shall authenticate and deliver, in the name of the designated transferee or transferees, one

or more new Notes of any authorized denominations and of a like aggregate principal amount and bearing such restrictive legends as may

be required by this Indenture.

Notes may be exchanged for other Notes of any

authorized denominations and of a like aggregate principal amount, upon surrender of the Notes to be exchanged at any such office or

agency maintained by the Company pursuant to ‎Section 4.02. Whenever any Notes are so surrendered for exchange, the Company

shall execute, and the Trustee shall authenticate and deliver, the Notes that the Holder making the exchange is entitled to receive,

bearing registration numbers not contemporaneously outstanding.

All Notes presented or surrendered for registration

of transfer or for exchange, repurchase or conversion shall (if so required by the Company, the Trustee, the Note Registrar or any co-Note

Registrar) be duly endorsed, or be accompanied by a written instrument or instruments of transfer in form attached hereto as an exhibit

to the Form of Note and duly executed, by the Holder thereof or its attorney-in-fact duly authorized in writing.

No service charge shall be imposed by the Company,

the Trustee, the Note Registrar, any co-Note Registrar or the Paying Agent for any exchange or registration of transfer of Notes, but

the Company and the Trustee may require a Holder to pay a sum sufficient to cover any documentary, stamp or similar issue or transfer

tax required in connection therewith as a result of the name of the Holder of new Notes issued upon such exchange or registration of

transfer being different from the name of the Holder of the old Notes surrendered for exchange or registration of transfer.

None of the Company, the Trustee, the Note Registrar

or any co-Note Registrar shall be required to exchange or register a transfer of (i) any Notes surrendered for conversion or, if

a portion of any Note is surrendered for conversion, such portion thereof surrendered for conversion, (ii) any Notes, or a portion

of any Note, surrendered for repurchase (and not withdrawn) in accordance with ‎Article 15 or (iii) any Notes selected

for redemption in accordance with ‎Article 16, except the unredeemed portion of any Note being redeemed in part.

In connection with any proposed transfer involving

Physical Notes, or any exchange of Global Notes for Physical Notes, the transferor shall provide or cause to be provided to the Trustee

all information necessary to allow the Trustee to comply with any applicable tax reporting obligations, including without limitation

any cost basis reporting obligations under Internal Revenue Code Section 6045. The Trustee may rely on the information provided

to it and shall have no responsibility to verify or ensure the accuracy of such information.

All Notes issued upon any registration of transfer

or exchange of Notes in accordance with this Indenture shall be the valid obligations of the Company, evidencing the same debt, and entitled

to the same benefits under this Indenture as the Notes surrendered upon such registration of transfer or exchange.

(b)            So

long as the Notes are eligible for book-entry settlement with the Depositary, unless otherwise required by law, subject to the fourth

paragraph from the end of ‎Section 2.05(c) all Notes shall be represented by one or more Notes in global form (each,

a “Global Note”) registered in the name of the Depositary or the nominee of the Depositary. The transfer and exchange

of beneficial interests in a Global Note that does not involve the issuance of a Physical Note shall be effected through the Depositary

(but not the Trustee or the Custodian) in accordance with this Indenture (including the restrictions on transfer set forth herein) and

the procedures of the Depositary therefor.

Note that bears or is required under this ‎Section 2.05(c) to bear the legend set forth in this ‎Section 2.05(c) (together

with any Common Stock issued upon conversion of the Notes that is required to bear the legend set forth in ‎Section 2.05(d),

collectively, the “Restricted Securities”) shall be subject to the restrictions on transfer set forth in this ‎Section 2.05(c) (including

the legend set forth below), unless such restrictions on transfer shall be eliminated or otherwise waived by written consent of the Company,

and the Holder of each such Restricted Security, by such Holder’s acceptance thereof, agrees to be bound by all such restrictions

on transfer. As used in this ‎Section 2.05(c) and ‎Section 2.05(d), the term “transfer”

encompasses any sale, pledge, transfer or other disposition whatsoever of any Restricted Security.

Until the date (the “Resale Restriction

Termination Date”) that is the later of (1) the date that is one year after the last date of original issuance of the

Notes, or such shorter period of time as permitted by Rule 144 or any successor provision thereto, and (2) such later date,

if any, as may be required by applicable law, any certificate evidencing such Note (and all securities issued in exchange therefor or

substitution thereof, other than Common Stock, if any, issued upon conversion thereof, which shall bear the legend set forth in ‎Section 2.05(d),

if applicable) shall bear a legend in substantially the following form (unless such Notes have been transferred pursuant to a registration

statement that has become effective under the Securities Act and that continues to be effective at the time of such transfer, or sold

pursuant to the exemption from registration provided by Rule 144 or any similar provision then in force under the Securities Act,

or unless otherwise agreed by the Company in writing, with notice thereof to the Trustee):

THIS SECURITY AND THE COMMON STOCK, IF ANY, ISSUABLE

UPON CONVERSION OF THIS SECURITY HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE “SECURITIES ACT”),

AND MAY NOT BE OFFERED, SOLD, PLEDGED OR OTHERWISE TRANSFERRED EXCEPT IN ACCORDANCE WITH THE FOLLOWING SENTENCE. BY ITS ACQUISITION

HEREOF OR OF A BENEFICIAL INTEREST HEREIN, THE ACQUIRER:

(1)            REPRESENTS

THAT IT AND ANY ACCOUNT FOR WHICH IT IS ACTING IS A “QUALIFIED INSTITUTIONAL BUYER” (WITHIN THE MEANING OF RULE 144A UNDER

THE SECURITIES ACT) AND THAT IT EXERCISES SOLE INVESTMENT DISCRETION WITH RESPECT TO EACH SUCH ACCOUNT, AND

(2)            AGREES

FOR THE BENEFIT OF PTC THERAPEUTICS, INC. (THE “COMPANY”) THAT IT WILL NOT OFFER, SELL, PLEDGE OR OTHERWISE

TRANSFER THIS SECURITY OR ANY BENEFICIAL INTEREST HEREIN PRIOR TO THE DATE THAT IS THE LATER OF (X) ONE YEAR AFTER THE LAST DATE

OF ORIGINAL ISSUANCE HEREOF OR SUCH SHORTER PERIOD OF TIME AS PERMITTED BY RULE 144 UNDER THE SECURITIES ACT OR ANY SUCCESSOR PROVISION

THERETO AND (Y) SUCH LATER DATE, IF ANY, AS MAY BE REQUIRED BY APPLICABLE LAW, EXCEPT:

(A)            TO

THE COMPANY OR ANY SUBSIDIARY THEREOF, OR

(B)            PURSUANT

TO A REGISTRATION STATEMENT THAT HAS BECOME EFFECTIVE UNDER THE SECURITIES ACT, OR

A PERSON REASONABLY BELIEVED TO BE A QUALIFIED INSTITUTIONAL BUYER IN COMPLIANCE WITH RULE 144A UNDER THE SECURITIES ACT, OR

(D)            PURSUANT

TO AN EXEMPTION FROM REGISTRATION PROVIDED BY RULE 144 UNDER THE SECURITIES ACT OR ANY OTHER AVAILABLE EXEMPTION FROM THE REGISTRATION

REQUIREMENTS OF THE SECURITIES ACT.

PRIOR TO THE REGISTRATION OF ANY TRANSFER IN ACCORDANCE

WITH CLAUSE (2)(D) ABOVE, THE COMPANY AND THE TRUSTEE RESERVE THE RIGHT TO REQUIRE THE DELIVERY OF SUCH LEGAL OPINIONS, CERTIFICATIONS

OR OTHER EVIDENCE AS MAY REASONABLY BE REQUIRED IN ORDER TO DETERMINE THAT THE PROPOSED TRANSFER IS BEING MADE IN COMPLIANCE WITH

THE SECURITIES ACT AND APPLICABLE STATE SECURITIES LAWS. NO REPRESENTATION IS MADE AS TO THE AVAILABILITY OF ANY EXEMPTION FROM THE REGISTRATION

REQUIREMENTS OF THE SECURITIES ACT.

No transfer of any Note prior to the Resale Restriction

Termination Date will be registered by the Note Registrar unless the applicable box on the Form of Assignment and Transfer has

been checked.

Any Note (or security issued in exchange or substitution

therefor) (i) as to which such restrictions on transfer shall have expired in accordance with their terms, (ii) that has

been transferred pursuant to a registration statement that has become effective under the Securities Act and that continues to be effective

at the time of such transfer or (iii) that has been sold pursuant to the exemption from registration provided by Rule 144

or any similar provision then in force under the Securities Act, may, upon surrender of such Note for exchange to the Note Registrar

in accordance with the provisions of this ‎Section 2.05, be exchanged for a new Note or Notes, of like tenor and aggregate

principal amount, which shall not bear the restrictive legend required by this ‎Section 2.05(c) and shall not be assigned

a restricted CUSIP number. In the case of the registration of any transfer of the Notes or the Common Stock, if any, issuable upon conversion

of the Notes, pursuant to an exemption from registration provided by Rule 144 or any other available exemption from the registration

requirements of the Securities Act prior to the Resale Restriction Termination Date, the Company and the Trustee reserve the right to

require the delivery of such legal opinions, certifications or other evidence as may reasonably be required stating that the proposed

transfer is being made in compliance with the Securities Act and applicable state securities laws. The restrictive legend set forth above

and affixed on any Note will be deemed, in accordance with the terms of the certificate representing such Note, to be removed therefrom

upon the Company’s delivery to the Trustee of written notice to such effect (and, for the avoidance of doubt, such notice need

not be accompanied by an Officers’ Certificate or an Opinion of Counsel in order to be effective to cause such restrictive legend

to be deemed to be removed from such Note), without further action by the Company, the Trustee, the Holder(s) thereof or any other

Person other than as specified in ‎Section 4.06(e). Subject to ‎Section 4.06(e), if such Note bears a “restricted”

CUSIP number at the time of such delivery, then, upon such delivery, such Note will be deemed, pursuant to this ‎Section 2.05(c) and

the footnote to the CUSIP number set forth on the face of the certificate representing such Note, to thereafter bear the “unrestricted”

CUSIP number identified in such footnote.

The Company shall be entitled to instruct the

Custodian in writing to so surrender any Global Note as to which any of the conditions set forth in clause (i) through (iii) of

the immediately preceding sentence have been satisfied, and, upon such instruction, the Custodian shall so surrender such Global Note

for exchange; and any new Global Note so exchanged therefor shall not bear the restrictive legend specified in this ‎Section 2.05(c) and

shall not be assigned a restricted CUSIP number; provided that the Depositary of any Global Note may require a mandatory exchange

or other process to cause such Global Note to be identified by an unrestricted CUSIP number in the facilities of such Depositary. The

Company shall promptly notify the Trustee in writing upon the occurrence of the Resale Restriction Termination Date and promptly after

a registration statement, if any, with respect to the Notes or any Common Stock issued upon conversion of the Notes has become effective

under the Securities Act. Any exchange pursuant to the foregoing paragraph shall be in accordance with the applicable procedures of the

Depositary.

Notwithstanding any other provisions of this Indenture

(other than the provisions set forth in this ‎Section 2.05(c)), a Global Note may not be transferred as a whole or in part

except (i) by the Depositary to a nominee of the Depositary or by a nominee of the Depositary to the Depositary or another nominee

of the Depositary or by the Depositary or any such nominee to a successor Depositary or a nominee of such successor Depositary and (ii) for

exchange of a Global Note or a portion thereof for one or more Physical Notes in accordance with the second immediately succeeding paragraph.

The Depositary shall be a clearing agency registered

under the Exchange Act. The Company initially appoints The Depository Trust Company to act as Depositary with respect to each Global

Note. Initially, each Global Note shall be issued to the Depositary, registered in the name of Cede & Co., as the nominee of

the Depositary, and deposited with the Trustee as custodian for Cede & Co.

If (i) the Depositary notifies the Company

at any time that the Depositary is unwilling or unable to continue as depositary for the Global Notes and a successor depositary is not

appointed within 90 days, (ii) the Depositary ceases to be registered as a clearing agency under the Exchange Act and a successor

depositary is not appointed within 90 days or (iii) an Event of Default with respect to the Notes has occurred and is continuing

and a beneficial owner of any Note requests that its beneficial interest therein be issued as a Physical Note, the Company shall execute,

and the Trustee, upon receipt of an Officers’ Certificate and a Company Order for the authentication and delivery of Notes, shall

authenticate and deliver (x) in the case of clause (iii), a Physical Note to such beneficial owner in a principal amount equal

to the principal amount of such Note corresponding to such beneficial owner’s beneficial interest and (y) in the case of

clause (i) or (ii), Physical Notes to each beneficial owner of the related Global Notes (or a portion thereof) in an aggregate

principal amount equal to the aggregate principal amount of such Global Notes in exchange for such Global Notes, and upon delivery of

the Global Notes to the Trustee such Global Notes shall be canceled.

Physical Notes issued in exchange for all or a

part of the Global Note pursuant to this ‎Section 2.05(c) shall be registered in such names and in such authorized denominations

as the Depositary, pursuant to instructions from its direct or indirect participants or otherwise, or, in the case of clause (iii) of

the immediately preceding paragraph, the relevant beneficial owner, shall instruct the Trustee. Upon execution and authentication, the

Trustee shall deliver such Physical Notes to the Persons in whose names such Physical Notes are so registered.

At such time as all interests in a Global Note

have been converted, canceled, repurchased, redeemed or transferred, such Global Note shall be, upon receipt thereof, canceled by the

Trustee in accordance with standing procedures and existing instructions between the Depositary and the Custodian. At any time prior

to such cancellation, if any interest in a Global Note is exchanged for Physical Notes, converted, canceled, repurchased, redeemed or

transferred to a transferee who receives Physical Notes therefor or any Physical Note is exchanged or transferred for part of such Global

Note, the principal amount of such Global Note shall, in accordance with the standing procedures and instructions existing between the

Depositary and the Custodian, be appropriately reduced or increased, as the case may be, and an endorsement shall be made on such Global

Note, by the Trustee or the Custodian, at the direction of the Trustee, to reflect such reduction or increase.

None of the Company, the Trustee, the Paying Agent,

the Conversion Agent, the Note Registrar or any agent of the Company or the Trustee shall have any responsibility or liability for any

aspect of the records relating to or payments made on account of beneficial ownership interests of a Global Note or maintaining, supervising

or reviewing any records relating to such beneficial ownership interests. None of the Company, the Trustee, the Paying Agent, the Conversion

Agent, the Note Registrar or any agent of the Company or the Trustee shall have any responsibility or liability for any act or omission

of the Depositary.

Neither the Company nor the Trustee shall have

any responsibility or liability for any act or omission of the Depositary. All notices and communications to be given to the Holders

and all payments to be made to Holders in respect of the Notes shall be given or made only to, or upon the order of the registered Holder(s),

which shall be the Depositary or its nominee in the case of a Global Note. The Trustee shall have no obligation or duty to monitor, determine

or inquire as to compliance with any securities laws or restrictions on transfer imposed under this Indenture or under applicable law

with respect to any transfer of any interest in any Note (including any transfers between or among Depositary participants or beneficial

owners of interests in any Global Note) other than to require delivery of such certificates and other documentation or evidence as are

expressly required by, and to do so if and when expressly required by the terms of, this Indenture, and to examine the same to determine

substantial compliance as to form with the express requirements hereof.

Except as set forth in the fourth and fifth immediately

preceding paragraphs, the rights of beneficial owners in any Global Note shall be exercised only through the Depositary subject to the

applicable procedures of the Depositary. The Trustee may rely and shall be fully protected in relying upon information furnished by the

Depositary with respect to its members, participants and beneficial owners.

(d)            Until

the Resale Restriction Termination Date, any stock certificate representing Common Stock issued upon conversion of a Note shall bear

a legend in substantially the following form (unless such Common Stock has been transferred pursuant to a registration statement that

has become effective under the Securities Act and that continues to be effective at the time of such transfer, or pursuant to the exemption

from registration provided by Rule 144 or any similar provision then in force under the Securities Act, or such Common Stock has

been issued upon conversion of a Note that has been transferred pursuant to a registration statement that has become effective under

the Securities Act and that continues to be effective at the time of such transfer, or pursuant to the exemption from registration provided

by Rule 144 or any similar provision then in force under the Securities Act, or unless otherwise agreed by the Company with written

notice thereof to the Trustee and any transfer agent for the Common Stock):

THIS SECURITY HAS NOT BEEN REGISTERED UNDER THE

SECURITIES ACT OF 1933, AS AMENDED (THE “SECURITIES ACT”), AND MAY NOT BE OFFERED, SOLD, PLEDGED OR OTHERWISE

TRANSFERRED EXCEPT IN ACCORDANCE WITH THE FOLLOWING SENTENCE. BY ITS ACQUISITION HEREOF OR OF A BENEFICIAL INTEREST HEREIN, THE ACQUIRER:

(1)            REPRESENTS

THAT IT AND ANY ACCOUNT FOR WHICH IT IS ACTING IS A “QUALIFIED INSTITUTIONAL BUYER” (WITHIN THE MEANING OF RULE 144A UNDER

THE SECURITIES ACT) AND THAT IT EXERCISES SOLE INVESTMENT DISCRETION WITH RESPECT TO EACH SUCH ACCOUNT, AND

(2)            AGREES

FOR THE BENEFIT OF PTC THERAPEUTICS, INC. (THE “COMPANY”) THAT IT WILL NOT OFFER, SELL, PLEDGE OR OTHERWISE

TRANSFER THIS SECURITY OR ANY BENEFICIAL INTEREST HEREIN PRIOR TO THE DATE THAT IS THE LATER OF (X) ONE YEAR AFTER THE LAST DATE

OF ORIGINAL ISSUANCE OF THE SERIES OF NOTES UPON THE CONVERSION OF WHICH THIS SECURITY WAS ISSUED OR SUCH SHORTER PERIOD OF TIME AS PERMITTED

BY RULE 144 UNDER THE SECURITIES ACT OR ANY SUCCESSOR PROVISION THERETO AND (Y) SUCH LATER DATE, IF ANY, AS MAY BE

REQUIRED BY APPLICABLE LAW, EXCEPT:

(A)            TO

THE COMPANY OR ANY SUBSIDIARY THEREOF, OR

(B)            PURSUANT

TO A REGISTRATION STATEMENT THAT HAS BECOME EFFECTIVE UNDER THE SECURITIES ACT, OR

A PERSON REASONABLY BELIEVED TO BE A QUALIFIED INSTITUTIONAL BUYER IN COMPLIANCE WITH RULE 144A UNDER THE SECURITIES ACT, OR

(D)            PURSUANT

TO AN EXEMPTION FROM REGISTRATION PROVIDED BY RULE 144 UNDER THE SECURITIES ACT OR ANY OTHER AVAILABLE EXEMPTION FROM THE REGISTRATION

REQUIREMENTS OF THE SECURITIES ACT.

PRIOR TO THE REGISTRATION OF ANY TRANSFER IN ACCORDANCE

WITH CLAUSE (2)(D) ABOVE, THE COMPANY AND THE TRANSFER AGENT FOR THE COMPANY’S COMMON STOCK RESERVE THE RIGHT TO REQUIRE

THE DELIVERY OF SUCH LEGAL OPINIONS, CERTIFICATIONS OR OTHER EVIDENCE AS MAY REASONABLY BE REQUIRED IN ORDER TO DETERMINE THAT

THE PROPOSED TRANSFER IS BEING MADE IN COMPLIANCE WITH THE SECURITIES ACT AND APPLICABLE STATE SECURITIES LAWS. NO REPRESENTATION IS

MADE AS TO THE AVAILABILITY OF ANY EXEMPTION FROM THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT.

Any such Common Stock (i) as to which such

restrictions on transfer shall have expired in accordance with their terms, (ii) that has been transferred pursuant to a registration

statement that has become effective under the Securities Act and that continues to be effective at the time of such transfer or (iii) that

has been sold pursuant to the exemption from registration provided by Rule 144 or any similar provision then in force under the

Securities Act, may, upon surrender of the certificates representing such shares of Common Stock for exchange in accordance with the

procedures of the transfer agent for the Common Stock, be exchanged for a new certificate or certificates for a like aggregate number

of shares of Common Stock, which shall not bear the restrictive legend required by this ‎Section 2.05(d).

(e)            Any

Note or Common Stock issued upon the conversion or exchange of a Note that is repurchased or owned by the Company or any Affiliate of

the Company (or any Person who was an Affiliate of the Company at any time during the three months immediately preceding) may not be

resold by the Company or such Affiliate (or such Person, as the case may be) unless registered under the Securities Act or resold pursuant

to an exemption from the registration requirements of the Securities Act in a transaction that results in such Note or Common Stock,

as the case may be, no longer being a “restricted security” (as defined under Rule 144).

(f)            Notwithstanding

anything contained herein to the contrary, neither the Trustee nor the Note Registrar shall be responsible for ascertaining whether any

transfer complies with the registration provisions of, or exemptions from, the Securities Act, applicable state securities law or other

applicable law.

Section 2.06. Mutilated, Destroyed, Lost

or Stolen Notes. In case any Note shall become mutilated or be destroyed, lost or stolen, the Company in its discretion may execute,

and upon receipt of a Company Order the Trustee or an authenticating agent appointed by the Trustee shall authenticate and deliver, a

new Note, bearing a registration number not contemporaneously outstanding, in exchange and substitution for the mutilated Note, or in

lieu of and in substitution for the Note so destroyed, lost or stolen. In every case the applicant for a substituted Note shall furnish

to the Company, to the Trustee and, if applicable, to such authenticating agent such security or indemnity as may be required by them

to save each of them harmless from any loss, liability, cost or expense caused by or connected with such substitution, and, in every

case of destruction, loss or theft, the applicant shall also furnish to the Company, to the Trustee and, if applicable, to such authenticating

agent evidence to their satisfaction of the destruction, loss or theft of such Note and of the ownership thereof.

The Trustee or such authenticating agent may authenticate

any such substituted Note and deliver the same upon the receipt of a Company Order and such security or indemnity as the Trustee, the

Company and, if applicable, such authenticating agent may require. No service charge shall be imposed by the Company, the Trustee, the

Note Registrar, any co-Note Registrar or the Paying Agent upon the issuance of any substitute Note, but the Company may require a Holder

to pay a sum sufficient to cover any documentary, stamp or similar issue or transfer tax required in connection therewith as a result

of the name of the Holder of the new substitute Note being different from the name of the Holder of the old Note that became mutilated

or was destroyed, lost or stolen. In case any Note that has matured or is about to mature or has been surrendered for required repurchase

or is about to be converted in accordance with ‎Article 14 shall become mutilated or be destroyed, lost or stolen, the Company

may, in its sole discretion, instead of issuing a substitute Note, pay or authorize the payment of or convert or authorize the conversion

of the same (without surrender thereof except in the case of a mutilated Note), as the case may be, if the applicant for such payment

or conversion shall furnish to the Company, to the Trustee and, if applicable, to such authenticating agent such security or indemnity

as may be required by them to save each of them harmless for any loss, liability, cost or expense caused by or connected with such substitution,

and, in every case of destruction, loss or theft, evidence satisfactory to the Company, the Trustee and, if applicable, any Paying Agent

or Conversion Agent evidence of their satisfaction of the destruction, loss or theft of such Note and of the ownership thereof.

Every substitute Note issued pursuant to the provisions

of this ‎Section 2.06 by virtue of the fact that any Note is destroyed, lost or stolen shall constitute an additional contractual

obligation of the Company, whether or not the destroyed, lost or stolen Note shall be found at any time, and shall be entitled to all

the benefits of (but shall be subject to all the limitations set forth in) this Indenture equally and proportionately with any and all

other Notes duly issued hereunder. To the extent permitted by law, all Notes shall be held and owned upon the express condition that

the foregoing provisions are exclusive with respect to the replacement, payment, redemption, conversion or repurchase of mutilated, destroyed,

lost or stolen Notes and shall preclude any and all other rights or remedies notwithstanding any law or statute existing or hereafter

enacted to the contrary with respect to the replacement, payment, redemption, conversion or repurchase of negotiable instruments or other

securities without their surrender.

Section 2.07. Temporary Notes. Pending

the preparation of Physical Notes, the Company may execute and the Trustee or an authenticating agent appointed by the Trustee shall,

upon receipt of a Company Order, authenticate and deliver temporary Notes (printed or lithographed). Temporary Notes shall be issuable

in any authorized denomination, and substantially in the form of the Physical Notes but with such omissions, insertions and variations

as may be appropriate for temporary Notes, all as may be determined by the Company. Every such temporary Note shall be executed by the

Company and authenticated by the Trustee or such authenticating agent upon the same conditions and in substantially the same manner,

and with the same effect, as the Physical Notes. Without unreasonable delay, the Company shall execute and deliver to the Trustee or

such authenticating agent Physical Notes (other than any Global Note) and thereupon any or all temporary Notes (other than any Global

Note) may be surrendered in exchange therefor, at each office or agency maintained by the Company pursuant to ‎Section 4.02

and the Trustee or such authenticating agent shall authenticate and deliver in exchange for such temporary Notes an equal aggregate principal

amount of Physical Notes. Such exchange shall be made by the Company at its own expense and without any charge therefor. Until so exchanged,

the temporary Notes shall in all respects be entitled to the same benefits and subject to the same limitations under this Indenture as

Physical Notes authenticated and delivered hereunder.

Section 2.08. Cancellation of Notes Paid,

Converted, Etc. The Company shall cause all Notes surrendered for the purpose of payment at maturity, repurchase upon a Fundamental

Change, redemption, registration of transfer or exchange or conversion, if surrendered to any Person other than the Trustee (including

any of the Company’s agents, Subsidiaries or Affiliates), to be surrendered to the Trustee for cancellation. All such Notes delivered

to the Trustee for cancellation shall be canceled by it in accordance with its customary procedures upon receipt of a written cancellation

order from the Company. Except for any Notes surrendered for registration of transfer or exchange, or as otherwise expressly permitted

by any of the provisions of this Indenture, no Notes shall be authenticated in exchange for any Notes surrendered to the Trustee for

cancellation.

Section 2.09. CUSIP Numbers. The

Company in issuing the Notes may use CUSIP numbers (if then generally in use), and, if so, the Company and/or the Trustee shall use CUSIP

numbers in all notices issued to Holders as a convenience to such Holders; provided that the Trustee shall have no liability for

any defect in the CUSIP number as they appear on any Notes, notice or elsewhere and that any such notice may state that no representation

is made as to the correctness of such numbers either as printed on the Notes or on such notice and that reliance may be placed only on

the other identification numbers printed on the Notes. The Company shall promptly notify the Trustee in writing of any change in the

CUSIP numbers.

Section 2.10. Additional Notes; Repurchases.

The Company may, without the consent of, or notice to, the Holders and notwithstanding ‎Section 2.01, reopen this Indenture

and issue additional Notes hereunder with the same terms as the Notes initially issued hereunder (other than differences in the issue

date, the issue price, Special Interest, if any, accrued prior to the issue date of such additional Notes, and, if applicable, restrictions

on transfer in respect of such additional Notes, including the date by which any restrictive legends must be removed) in an unlimited

aggregate principal amount; provided that if any such additional Notes are not fungible with the Notes initially issued hereunder

for U.S. federal income tax purposes or securities law purposes, such additional Notes shall have one or more separate CUSIP numbers

or no CUSIP number. Prior to the issuance of any such additional Notes, the Company shall deliver to the Trustee a Company Order, an

Officers’ Certificate and an Opinion of Counsel, such Officers’ Certificate and Opinion of Counsel to cover such matters,

in addition to those required by ‎Section 17.05, as the Trustee shall reasonably request. In addition, the Company may, to

the extent permitted by law, and, without the consent of Holders, directly or indirectly (regardless of whether such Notes are surrendered

to the Company), repurchase Notes in the open market or otherwise, whether by the Company or its Subsidiaries or through a privately

negotiated transaction or public tender or exchange offer or through counterparties to private agreements, including by cash-settled

swaps or other derivatives. The Company may, at its option and to the extent permitted by applicable law, reissue, resell or surrender

to the Trustee for cancellation in accordance with ‎Section 2.08 any Notes that the Company may repurchase other than Notes

repurchased in connection with a Fundamental Change (and in the case of a reissuance or resale, so long as such Notes do not constitute

“restricted securities” (as defined under Rule 144) upon such reissuance or resale; provided that if any such

reissued or resold Notes are not fungible with the Notes issued on the date hereof under this Indenture for U.S. federal income tax purposes,

such reissued or resold Notes shall have one or more separate CUSIP numbers or no CUSIP number). Any Notes that the Company may repurchase,

other than Notes repurchased in connection with a Fundamental Change, shall be considered outstanding under this Indenture (except for

voting purposes) unless and until such time the Company surrenders them to the Trustee for cancellation and, upon receipt of a Company

Order, the Trustee shall cancel all Notes so surrendered in accordance with ‎Section 2.08.

Article 3

Satisfaction and Discharge

Section 3.01. Satisfaction and Discharge.

This Indenture and the Notes shall upon request of the Company contained in an Officers’ Certificate cease to be of further effect,

and the Trustee, at the expense of the Company, shall execute such instruments reasonably requested by the Company acknowledging satisfaction

and discharge of this Indenture and the Notes, when (a) (i) all Notes theretofore authenticated and delivered (other than

(x) Notes which have been destroyed, lost or stolen and which have been replaced, paid or converted as provided in ‎Section 2.06

and (y) Notes for whose payment money has heretofore been deposited in trust or segregated and held in trust by the Company and

thereafter repaid to the Company or discharged from such trust, as provided in ‎Section 4.04(d)) have been delivered to the

Trustee for cancellation; or (ii) the Company has deposited with the Trustee or the transfer agent for the Common Stock or delivered

to Holders, as applicable, after the Notes have become due and payable, whether on the Maturity Date, any Redemption Date, any Fundamental

Change Repurchase Date, upon conversion or otherwise, cash or cash, shares of Common Stock or a combination thereof, as applicable, solely

to satisfy the Company’s Conversion Obligation, sufficient to pay all of the outstanding Notes and all other sums due and payable

under this Indenture by the Company; and (b) the Company has delivered to the Trustee an Officers’ Certificate and an Opinion

of Counsel, each stating that all conditions precedent herein provided for relating to the satisfaction and discharge of this Indenture

and the Notes have been complied with. Notwithstanding the satisfaction and discharge of this Indenture and the Notes, the obligations

of the Company to the Trustee under ‎Section 7.06 shall survive.

Article 4

Particular Covenants of the Company

Section 4.01. Payment of Principal and

Interest. The Company covenants and agrees that it will pay, or cause the Paying Agent to pay, the principal (including the Redemption

Price and the Fundamental Change Repurchase Price, if applicable) of, any accrued and unpaid Special Interest on, and consideration due

upon conversion of, each of the Notes at the places, at the respective times and in the manner provided herein and in the Notes.

Section 4.02. Maintenance of Office or

Agency. The Company will maintain in the United States of America, an office or agency where the Notes may be surrendered for registration

of transfer or exchange or for presentation for payment or repurchase (“Paying Agent”) or for conversion (“Conversion

Agent”) and where notices and demands to or upon the Company in respect of the Notes and this Indenture may be served. The

Company may change the location of the Paying Agent or the Conversion Agent within the contiguous United States, without providing prior

notice to the Holders but will give prompt written notice to the Trustee of the location, and any change in the location, of such office

or agency. If at any time the Company shall fail to maintain any such required office or agency or shall fail to furnish the Trustee

with the address thereof, such presentations, surrenders, notices and demands may be made or served at the Corporate Trust Office or

the office or agency of the Trustee in the United States of America; provided, however, that the Trustee shall not be deemed an

agent of the Company for service of legal process. The Company may serve as Paying Agent or Conversion Agent.

The Company may also from time to time designate

as co-Note Registrars one or more other offices or agencies where the Notes may be presented or surrendered for any or all such purposes

and may from time to time rescind such designations; provided that no such designation or rescission shall in any manner relieve

the Company of its obligation to maintain an office or agency in the United States of America, for such purposes. The Company will give

prompt written notice to the Trustee of any such designation or rescission and of any change in the location of any such other office

or agency. The Company may serve as Note Registrar. The terms “Paying Agent” and “Conversion Agent”

include any such additional or other offices or agencies, as applicable.

The Company hereby initially designates the Trustee

as the Paying Agent, Note Registrar, Custodian and Conversion Agent and the Corporate Trust Office as the office or agency in the United

States of America, where Notes may be surrendered for registration of transfer or exchange or for presentation for payment or repurchase

or for conversion and where notices and demands to or upon the Company in respect of the Notes and this Indenture may be served.

Section 4.03. Appointments to Fill Vacancies

in the Trustee’s Role. The Company, whenever necessary to avoid or fill a vacancy in the role of Trustee, will appoint, in

the manner provided in ‎Section 7.09, a Trustee, so that there shall at all times be a Trustee hereunder.

Section 4.04. Provisions as to Paying

Agent. (a) If the Company shall appoint a Paying Agent other than the Trustee, the Company will cause such Paying Agent to

execute and deliver to the Trustee an instrument in which such agent shall agree with the Trustee, subject to the provisions of this

‎Section 4.04:

(i)            that

it will hold all sums held by it as such agent for the payment of the principal (including the Redemption Price and the Fundamental Change

Repurchase Price, if applicable) of, any accrued and unpaid Special Interest on, and consideration due upon conversion of the Notes in

trust for the benefit of the Holders of the Notes;

(ii)            that

it will give the Trustee prompt written notice of any failure by the Company to make any payment of the principal (including the Redemption

Price and the Fundamental Change Repurchase Price, if applicable) of, any accrued and unpaid Special Interest on, and consideration due

upon conversion of the Notes when the same shall be due and payable; and

(iii)            that

at any time during the continuance of an Event of Default, upon request of the Trustee, it will forthwith pay to the Trustee all sums

so held in trust.

The Company shall, on or before each due date

of the principal (including the Redemption Price and the Fundamental Change Repurchase Price, if applicable) of, any accrued and unpaid

Special Interest on, or consideration due upon conversion of, the Notes, deposit with the Paying Agent a sum sufficient to pay such principal

(including the Redemption Price and the Fundamental Change Repurchase Price, if applicable), any accrued and unpaid Special Interest,

or such consideration due upon conversion and (unless such Paying Agent is the Trustee) the Company will promptly notify the Trustee

in writing of any failure to take such action; provided that if such deposit is made on the due date, such deposit must be received

by the Paying Agent by 11:00 a.m., New York City time, on such date.

(b)            If

the Company shall act as its own Paying Agent, it will, on or before each due date of the principal (including the Redemption Price and

the Fundamental Change Repurchase Price, if applicable) of, any accrued and unpaid Special Interest on, and consideration due upon conversion

of, the Notes, set aside, segregate and hold in trust for the benefit of the Holders of the Notes a sum sufficient to pay such principal

(including the Redemption Price and the Fundamental Change Repurchase Price, if applicable), any accrued and unpaid Special Interest

and such consideration due upon conversion so becoming due and will promptly notify the Trustee in writing of any failure to take such

action and of any failure by the Company to make any payment of the principal (including the Redemption Price and the Fundamental Change

Repurchase Price, if applicable) of, any accrued and unpaid Special Interest on, or consideration due upon conversion of, the Notes when

the same shall become due and payable.

in this ‎Section 4.04 to the contrary notwithstanding, the Company may, at any time, for the purpose of obtaining a satisfaction

and discharge of this Indenture, or for any other reason, pay, cause to be paid or deliver to the Trustee all sums or amounts held in

trust by the Company or any Paying Agent hereunder as required by this ‎Section 4.04, such sums or amounts to be held by the

Trustee upon the trusts herein contained and upon such payment or delivery by the Company or any Paying Agent to the Trustee, the Company

or such Paying Agent shall be released from all further liability but only with respect to such sums or amounts. Upon the occurrence

of any event specified in Section 6.01(h) or Section 6.01(i), the Trustee shall automatically become the Paying Agent.

(d)            Subject

to applicable law, including applicable escheatment laws, any money or property deposited with the Trustee, the Conversion Agent or any

Paying Agent in trust for the payment of the principal (including the Redemption Price and the Fundamental Change Repurchase Price, if

applicable) of or any accrued and unpaid Special Interest on, or any money and shares of Common Stock deposited with the transfer agent

for the Common Stock or then held by the Company in trust for the payment of the consideration due upon conversion of, any Note and remaining

unclaimed for two years after such principal (including the Redemption Price and the Fundamental Change Repurchase Price, if applicable),

any interest or consideration due upon conversion has become due and payable shall be paid to the Company on request of the Company contained

in an Officers’ Certificate, or (if then held by the Company) shall be discharged from such trust and the Trustee shall have no

further liability with respect to such funds; and the Holder of such Note shall thereafter, as an unsecured general creditor, look only

to the Company for payment thereof, and all liability of the Trustee, the Conversion Agent or such Paying Agent with respect to such

trust money and all liability of the transfer agent for the Common Stock with respect to such trust money and shares of Common Stock

shall thereupon cease.

(e)            Upon

any Event of Default pursuant to Section 6.01(h) or (i), the Trustee shall automatically be designated as the Paying Agent

for the Notes if the Trustee is not acting in such capacity at such time.

Section 4.05. Existence. Subject

to ‎Article 11, the Company shall do or cause to be done all things necessary to preserve and keep in full force and effect

its corporate existence.

Section 4.06. Rule 144A Information

Requirement and Annual Reports. (a)  At any time the Company is not subject to Section 13 or 15(d) of the Exchange

Act, the Company shall, so long as any of the Notes or any shares of Common Stock issuable upon conversion thereof shall, at such time,

constitute “restricted securities” within the meaning of Rule 144(a)(3) under the Securities Act, promptly provide

to the Trustee and, upon written request by any Holder or beneficial owner of any Notes, any Holder, beneficial owner or prospective

purchaser of such Notes or any shares of Common Stock issuable upon conversion of such Notes, the information required to be delivered

pursuant to Rule 144A(d)(4) under the Securities Act to facilitate the resale of such Notes or shares of Common Stock pursuant

to Rule 144A.

(b)            The

Company shall file with the Trustee, within 15 days after the same are required to be filed with the Commission (after giving effect

to the maximum grace period provided by Rule 12b-25 (or any successor rule thereto) under the Exchange Act (regardless of

whether the Company files or indicates in the related Form 12b-25 (or any successor form thereto) that it expects to file or will

file, such report before the expiration of such maximum period)), copies of any documents or reports that the Company is required to

file with the Commission pursuant to Section 13 or 15(d) of the Exchange Act (excluding any such information, documents or

reports, or portions thereof, subject to confidential treatment and any correspondence with the Commission). Any such document or report

that the Company files with the Commission via the Commission’s EDGAR system (or any successor thereto) shall be deemed to be filed

with the Trustee for purposes of this ‎Section 4.06(b) at the time such documents are filed via the EDGAR system (or

any successor thereto), it being understood that the Trustee shall not be responsible for determining whether such filings have been

made.

of the information, reports and documents described in subsections (a) and ‎(b) above to the Trustee is for informational

purposes only, and the Trustee’s receipt of such shall not constitute actual or constructive notice of any information contained

therein or determinable from information contained therein, including the Company’s compliance with any of its covenants hereunder

(as to which the Trustee is entitled to conclusively rely on an Officers’ Certificate). The Trustee shall have no liability or

responsibility for the filing, timeliness, or content of such reports. The Trustee shall not be obligated to monitor or confirm, on a

continuing basis or otherwise, the Company’s compliance with the covenants or with respect to any reports or other documents filed

with the Commission or posted to any website or participate in any conference calls.

(d)            If,

at any time during the six-month period beginning on, and including, the date that is six months after the last date of original issuance

of the Notes, the Company fails to timely file any document or report (other than current reports on Form 8-K) that it is required

to file with the Commission pursuant to Section 13 or 15(d) of the Exchange Act, as applicable (after giving effect to the

maximum grace period provided by Rule 12b-25 (or any successor rule thereto) under the Exchange Act (regardless of whether

the Company files or indicates in the related Form 12b-25 (or any successor form thereto) that it expects to file or will file,

such report before the expiration of such maximum period)), or the Notes are not Freely Tradable, then the Company shall pay Special

Interest on the Notes. Such Special Interest shall accrue on the Notes at the rate of 0.50% per annum of the principal amount of the

Notes outstanding for each day during such period for which the Company’s failure to file has occurred and is continuing or the

Notes are not Freely Tradable. As used in this ‎Section 4.06(d), documents or reports that the Company is required to “file”

with the Commission pursuant to Section 13 or 15(d) of the Exchange Act does not include documents or reports that the Company

furnishes to the Commission pursuant to Section 13 or 15(d) of the Exchange Act.

(e)            If,

and for so long as, the restrictive legend on the Notes specified in ‎Section 2.05(c) has not been, or is not deemed

to have been, removed in accordance with ‎Section 2.05(c), the Notes are assigned a restricted CUSIP number or the Notes are

not Freely Tradable as of the 380th day after the last date of original issuance of the Notes, the Company shall pay Special Interest

on the Notes at a rate equal to 0.50% per annum of the principal amount of Notes outstanding for each day from, and including, such 380th

day until the restrictive legend on the Notes has been, or is deemed to have been, removed in accordance with ‎Section 2.05(c),

the Notes are assigned an unrestricted CUSIP number and the Notes are Freely Tradable. The restrictive legend on the Notes shall be deemed

removed pursuant to the terms of this Indenture as provided in ‎Section 2.05(c), and, at such time, the Notes will, pursuant

to, and subject to the provisions of, such Section, be deemed assigned an unrestricted CUSIP number. However, for the avoidance of doubt,

for Notes that are not in certificated form, the Notes will continue to bear Special Interest pursuant to this ‎Section 4.06(e) until

such time as they are identified by an unrestricted CUSIP number in the facilities of the Depositary or any successor depositary for

the Notes, as a result of completion of the Depositary’s mandatory exchange process or otherwise. Such accrual of Special Interest

shall be the exclusive remedy available to Holders for the Company’s failure to remove the restrictive legend on the Notes specified

in ‎Section 2.05(c), the Notes being assigned a restricted CUSIP number or the Notes not otherwise being Freely Tradable as

described in this ‎Section 4.06(e).

(f)            Notwithstanding

anything herein to the contrary, Special Interest that accrues on the Notes for any period on or after the 380th day after the last date

of original issuance of the Notes pursuant to ‎Section 4.06(e) will not be payable on any Special Interest Payment Date

occurring on or after such date, unless (x) a Holder or beneficial owner of a Note (in the case of a beneficial owner subject to

the satisfactory verification of a beneficial owner’s identity and ownership) has delivered to the Company (with a copy to the

Trustee), before the Special Interest Record Date immediately before such Special Interest Payment Date, a written notice (a “Deferred

Special Interest Demand Request”) demanding payment of Special Interest; or (y) the Company, in its sole and absolute

discretion, elects, by sending notice of such election (a “Notice of Election to Pay Deferred Special Interest”) to

Holders (with a copy to the Trustee) before such Special Interest Record Date, to pay such Special Interest on such Special Interest

Payment Date (any such accrued and unpaid Special Interest that, in compliance with this ‎Section 4.06(f), is not paid on such

Special Interest Payment Date, “Deferred Special Interest”). Without further action by the Company or any other Person,

interest will automatically accrue on any Deferred Special Interest from, and including, the applicable Special Interest Payment Date

at a rate per annum equal to the then-applicable Special Interest rate to, but excluding, the date on which such Deferred Special Interest,

together with any interest thereon, is paid. Once any accrued and unpaid Special Interest becomes payable on a Special Interest Payment

Date, whether as a result of the delivery of a written notice pursuant to the foregoing or, if earlier, the Company’s election

to pay the same, Special Interest will thereafter not be subject to deferral pursuant to the foregoing. For the avoidance of doubt, the

failure to pay any accrued and unpaid Special Interest on a Special Interest Payment Date will not constitute a Default or an Event of

Default under this Indenture or the Notes if such payment is deferred in accordance with this ‎Section 4.06(f). Notwithstanding

anything to the contrary in this Indenture or the Notes, if (i) any unpaid Deferred Special Interest exists on any Notes as of

the close of business on the Special Interest Record Date immediately preceding the Maturity Date; (ii) no Holder or beneficial

owner of a Note has delivered a Deferred Special Interest Demand Request in the manner described above before such Special Interest Record

Date; and (iii) the Company has not sent a Notice of Election to Pay Deferred Special Interest in the manner described above before

such Special Interest Record Date, then Deferred Special Interest on each Note then outstanding will cease to accrue, and all Deferred

Special Interest, together with any interest thereon, on such Note will be deemed to be extinguished on the following date: (a) if

such Note is to be converted, the Conversion Date for such conversion (it being understood, for the avoidance of doubt, that the Conversion

Consideration therefor need not include, and the amount referred to in the fifth sentence of ‎Section 14.02(h) need not

include, the payment of any such Deferred Special Interest or any interest thereon); and (b) in all other cases, the later of (x) the

Maturity Date and (y) the first date on which the Company has repaid the principal of, and any accrued and unpaid Special Interest

(other than such Deferred Special Interest and any interest thereon) on, such Note in full.

(g)            Special

Interest will be payable in arrears on each Special Interest Payment Date following accrual as set forth in ‎Section 2.03(b).

(h)            The

Special Interest that is payable in accordance with ‎Section 4.06(d) or ‎Section 4.06(e) shall be in

addition to, and not in lieu of, any Special Interest that may be payable as a result of the Company’s election pursuant to ‎Section 6.03;

provided, however, that in no event shall any Special Interest that may accrue in accordance with ‎Section 4.06(d) as

a result of the Company’s failure to timely file any document or report as set forth therein, together with any Special Interest

that may accrue at the Company’s election pursuant to ‎Section 6.03, accrue at a rate in excess of 0.50% per annum on

any Notes, regardless of the number of events or circumstances giving rise to the requirement to pay such Special Interest.

(i)            If

Special Interest is payable by the Company pursuant to ‎Section 4.06(d) or ‎Section 4.06(e), the Company shall

deliver to the Trustee an Officers’ Certificate to that effect stating (i) the amount of such Special Interest that is payable

and (ii) the date on which such Special Interest is payable. Unless and until a Responsible Officer of the Trustee receives at

the Corporate Trust Office such a certificate, the Trustee may assume without inquiry that no such Special Interest is payable. If the

Company has paid Special Interest directly to the Persons entitled to it, the Company shall deliver to the Trustee an Officers’

Certificate setting forth the particulars of such payment. The Trustee shall have no duty to verify the Company’s determination

as to whether Special Interest is due or the Company’s calculations as to the amount of Special Interest, and may assume without

inquiry that no Special Interest is payable or has been deferred until written notice of such Special Interest being payable has been

provided to the Trustee by the Company.

Section 4.07. Stay, Extension and Usury

Laws. The Company covenants (to the extent that it may lawfully do so) that it shall not at any time insist upon, plead, or in any

manner whatsoever claim or take the benefit or advantage of, any stay, extension or usury law or other law that would prohibit or forgive

the Company from paying all or any portion of the principal of or any interest on the Notes as contemplated herein, wherever enacted,

now or at any time hereafter in force, or that may affect the covenants or the performance of this Indenture; and the Company (to the

extent it may lawfully do so) hereby expressly waives all benefit or advantage of any such law, and covenants that it will not, by resort

to any such law, hinder, delay or impede the execution of any power herein granted to the Trustee, but will suffer and permit the execution

of every such power as though no such law had been enacted.

Section 4.08. Compliance Certificate;

Statements as to Defaults. The Company shall deliver to the Trustee at its Corporate Trust Office, within 120 days after the end

of each fiscal year of the Company (beginning with the fiscal year ending on December 31, 2026), an Officers’ Certificate,

signed by the principal executive officer of the Company, the principal financial officer of the Company or the principal accounting

officer of the Company, stating whether the signers thereof have knowledge of any Default that occurred during the previous year.

In addition, the Company shall deliver to the

Trustee at its Corporate Trust Office, within 30 days after the occurrence of any Event of Default or Default, an Officers’ Certificate

setting forth the details of such Event of Default or Default, its status and the action that the Company is taking or proposing to take

in respect thereof; provided that no such Officers’ Certificate is required if the event that would constitute a Default

has been cured or waived before the date the Company is required to deliver such Officers’ Certificate.

Section 4.09. Further Instruments and

Acts. Upon request of the Trustee, the Company will execute and deliver such further instruments and do such further acts as may

be reasonably necessary or proper to carry out more effectively the purposes of this Indenture.

Article 5

Lists of Holders and Reports by the Company and the Trustee

Section 5.01. Lists of Holders. The

Company covenants and agrees that it will furnish or cause to be furnished to the Trustee and any Paying Agent (if other than the Trustee),

semi-annually, not more than 15 days after each June 1 and December 1 in each year beginning with December 1, 2026,

and at such other times as the Trustee may request in writing, within 30 days after receipt by the Company of any such request (or such

lesser time as the Trustee may reasonably request in order to enable it to timely provide any notice to be provided by it hereunder),

a list in such form as the Trustee may reasonably require of the names and addresses of the Holders as of a date not more than 15 days

(or such other date as the Trustee may reasonably request in order to so provide any such notices) prior to the time such information

is furnished, except that no such list need be furnished so long as the Trustee is acting as Note Registrar.

Section 5.02. Preservation and Disclosure

of Lists. The Trustee shall preserve, in as current a form as is reasonably practicable, all information as to the names and addresses

of the Holders contained in the most recent list furnished to it as provided in ‎Section 5.01 or maintained by the Trustee

in its capacity as Note Registrar, if so acting. The Trustee may destroy any list furnished to it as provided in ‎Section 5.01

upon receipt of a new list so furnished.

Article 6

Defaults and Remedies

Section 6.01. Events of Default.

Each of the following events shall be an “Event of Default” with respect to the Notes:

(a)            default

in any payment of any interest on any Note when due and payable, and the default continues for a period of 30 days;

(b)            default

in the payment of principal of any Note when due and payable on the Maturity Date, upon Optional Redemption, upon any required repurchase,

upon declaration of acceleration or otherwise;

by the Company to comply with its obligation to convert the Notes in accordance with this Indenture upon exercise of a Holder’s

conversion right and such failure continues for five Business Days;

(d)            failure

by the Company to issue a Fundamental Change Company Notice in accordance with ‎Section 15.02(c) or notice of a specified

corporate event in accordance with ‎Section 14.01(b)(ii) or ‎Section 14.01(b)(iii), in each case, when due,

and such failure continues for five Business Days;

(e)            failure

by the Company to comply with its obligations under ‎Article 11;

(f)            failure

by the Company for 60 days after written notice from the Trustee or the Holders of at least 25% in aggregate principal amount of the

Notes then outstanding has been received by the Company and the Trustee to comply with any of its other agreements contained in the Notes

or this Indenture;

(g)            default

by the Company or any Significant Subsidiary of the Company with respect to any mortgage, agreement or other instrument under which there

may be outstanding, or by which there may be secured or evidenced, any indebtedness for money borrowed in excess of $50,000,000 (or its

foreign currency equivalent) in the aggregate of the Company and/or any such Significant Subsidiary, whether such indebtedness now exists

or shall hereafter be created (i) resulting in such indebtedness becoming or being declared due and payable prior to its stated

maturity or (ii) constituting a failure to pay the principal or interest of any such indebtedness when due and payable at its stated

maturity, upon required repurchase, upon declaration of acceleration or otherwise and in the cases of clauses (i) and (ii), such

acceleration shall not, after the expiration of any applicable grace period, have been rescinded or annulled or such failure to pay or

default shall not have been cured or waived, or such indebtedness shall not have been paid or discharged, as the case may be, within

30 days after written notice to the Company by the Trustee or to the Company and the Trustee by Holders of at least 25% in aggregate

principal amount of Notes then outstanding;

(h)            the

Company or any Significant Subsidiary shall commence a voluntary case or other proceeding seeking liquidation, reorganization or other

relief with respect to the Company or any such Significant Subsidiary or its debts under any bankruptcy, insolvency or other similar

law now or hereafter in effect or seeking the appointment of a trustee, receiver, liquidator, custodian or other similar official of

the Company or any such Significant Subsidiary or any substantial part of its property, or shall consent to any such relief or to the

appointment of or taking possession by any such official in an involuntary case or other proceeding commenced against it, or shall make

a general assignment for the benefit of creditors, or shall fail generally to pay its debts as they become due; or

(i)            an

involuntary case or other proceeding shall be commenced against the Company or any Significant Subsidiary seeking liquidation, reorganization

or other relief with respect to the Company or such Significant Subsidiary or its debts under any bankruptcy, insolvency or other similar

law now or hereafter in effect or seeking the appointment of a trustee, receiver, liquidator, custodian or other similar official of

the Company or such Significant Subsidiary or any substantial part of its property, and such involuntary case or other proceeding shall

remain undismissed and unstayed for a period of 30 consecutive days.

Section 6.02. Acceleration; Rescission

and Annulment. If one or more Events of Default shall have occurred and be continuing (whatever the reason for such Event of Default

and whether it shall be voluntary or involuntary or be effected by operation of law or pursuant to any judgment, decree or order of any

court or any order, rule or regulation of any administrative or governmental body), then, and in each and every such case (other

than an Event of Default specified in ‎Section 6.01(h) or ‎Section 6.01(i) with respect to the Company

or any of its Significant Subsidiaries), unless the principal of all of the Notes shall have already become due and payable, either the

Trustee or the Holders of at least 25% in aggregate principal amount of the Notes then outstanding determined in accordance with ‎Section 8.04,

by notice in writing to the Company (and to the Trustee if given by Holders), may declare 100% of the principal of, and accrued and unpaid

Special Interest, if any, on, all the Notes to be due and payable immediately, and upon any such declaration the same shall become and

shall automatically be immediately due and payable, anything contained in this Indenture or in the Notes to the contrary notwithstanding.

If an Event of Default specified in ‎Section 6.01(h) or ‎Section 6.01(i) with respect to the Company

or any of its Significant Subsidiaries occurs and is continuing, 100% of the principal of, and accrued and unpaid Special Interest, if

any, on, all Notes shall become and shall automatically be immediately due and payable without any further act or declaration on the

part of the Holders or the Trustee.

The immediately preceding paragraph, however,

is subject to the conditions that if, at any time after the principal of the Notes shall have been so declared due and payable, and before

any judgment or decree for the payment of the monies due shall have been obtained or entered as hereinafter provided, the Company shall

pay or shall deposit with the Trustee a sum sufficient to pay installments of accrued and unpaid Special Interest, if any, upon all Notes

and the principal of any and all Notes that shall have become due otherwise than by acceleration (with any interest on overdue installments

of any accrued and unpaid Special Interest to the extent that payment of any such interest is enforceable under applicable law, and on

such principal at the then-applicable Special Interest rate borne by the Notes at such time) and amounts due to the Trustee pursuant

to ‎Section 7.06, and if (1) rescission would not conflict with any judgment or decree of a court of competent jurisdiction

and (2) any and all existing Events of Default under this Indenture, other than the nonpayment of the principal of and accrued

and unpaid Special Interest, if any, on Notes that shall have become due solely by such acceleration, shall have been cured or waived

pursuant to ‎Section 6.09, then and in every such case (except as provided in the immediately succeeding sentence) the Holders

of a majority in aggregate principal amount of the Notes then outstanding, by written notice to the Company and to the Trustee, may waive

all Defaults or Events of Default with respect to the Notes and rescind and annul such declaration and its consequences and such Default

shall cease to exist, and any Event of Default arising therefrom shall be deemed to have been cured for every purpose of this Indenture;

but no such waiver or rescission and annulment shall extend to or shall affect any subsequent Default or Event of Default, or shall impair

any right consequent thereon. Notwithstanding anything to the contrary herein, no such waiver or rescission and annulment shall extend

to or shall affect any continuing Default or Event of Default resulting from (i) the nonpayment of the principal (including the

Redemption Price and the Fundamental Change Repurchase Price, if applicable) of, or any accrued and unpaid Special Interest on, any Notes,

(ii) a failure to repurchase any Notes when required or (iii) a failure to pay or deliver, as the case may be, the consideration

due upon conversion of the Notes.

For the avoidance of doubt, and without limiting

the manner in which any Default can be cured, (a) any failure by the Company to provide any notice (other than a notice as described

in Section 6.01(d)) shall be subject to Section 6.01(f) (including the 60-day cure period contained therein), and any

related Default shall be deemed cured upon the sending of such notice whether or not the events or circumstances that are the subject

of such notice have already occurred at the time such notice is given, (b) a Default in making any payment on (or delivering any

other consideration in respect of) any Note will be cured upon the delivery, in accordance with the terms of this Indenture, of such

payment (or other consideration) together, if applicable, with any interest thereon, and (c) a Default that is (or, after notice

or passage of time or both, would be) an Event of Default relating to the failure to comply with the Company’s reporting obligations

in accordance with Section 6.03 will be cured upon the filing of the relevant report(s) that were required to be filed and

gave rise to such Default. In addition, for the avoidance of doubt, (i) if a Default that is not an Event of Default is cured or

waived before such Default would have constituted an Event of Default, then no Event of Default will result from such Default, and (ii) if

an Event of Default is cured or waived before any related notice of acceleration is delivered, such Event of Default shall be deemed

cured and the Notes shall not be subject to acceleration on account of such Default.

Section 6.03. Special Interest. Notwithstanding

anything in this Indenture or in the Notes to the contrary, to the extent the Company elects, the sole remedy for an Event of Default

relating to the Company’s failure to comply with its obligations as set forth in ‎Section 4.06(b) shall, for the

first 360 days after the occurrence of such an Event of Default (which, for the avoidance of doubt, shall not commence until the notice

described in Section 6.01(f) has been given and the related 60-day period set forth in Section 6.01(f) has passed),

consist exclusively of the right to receive Special Interest on the Notes at a rate equal to (i) 0.25% per annum of the principal

amount of the Notes outstanding for each day during the first 180-day period beginning on, and including, the date on which such an Event

of Default first occurs and (ii) 0.50% per annum of the principal amount of the Notes outstanding for each day during the period

from, and including, the 181st day after the occurrence of such Event of Default to, and including, the 360th day after the occurrence

of such Event of Default, in each case, during which such Event of Default is continuing. Subject to the second immediately succeeding

paragraph, Special Interest that may accrue pursuant to this ‎Section 6.03 shall be in addition to, not in lieu of, any Special

Interest that may accrue pursuant to ‎Section 4.06(d) or ‎Section 4.06(e). If the Company so elects, such Special

Interest shall be payable as set forth in ‎Section 2.03(b) and shall accrue on all outstanding Notes from, and including,

the date on which the Event of Default relating to the Company’s failure to comply with its obligations as set forth in Section 4.06(b) first

occurs to, and including, the 360th day thereafter (or such earlier date on which such Event of Default is cured or validly waived in

accordance with this Article 6); provided, however, that if the first date on which any Special Interest (including

Deferred Special Interest) begins to accrue on a Note is on or after the fifth Business Day before a Special Interest Record Date and

before the next Special Interest Payment Date, then, notwithstanding anything to the contrary in this Indenture, the amount thereof accruing

in respect of the period from, and including, such first date to, but excluding such Special Interest Payment Date will not be payable

on such Special Interest Payment Date but will instead be deemed to accrue (without duplication) entirely on such Special Interest Payment

Date (and, for the avoidance of doubt, no Special Interest will accrue as a result of the related delay). On the 361st day after such

Event of Default (if the Event of Default relating to the Company’s failure to comply with its obligations as set forth in Section 4.06(b) is

not cured or validly waived in accordance with this Article 6 prior to such 361st day), such Special Interest shall cease to accrue

and the Notes shall be immediately subject to acceleration as provided in ‎Section 6.02. The provisions of this ‎Section 6.03

will not affect the rights of Holders of Notes in the event of the occurrence of any other Event of Default other than the Company’s

failure to comply with its obligations as set forth in ‎‎Section 4.06(b). In the event the Company does not elect to pay

Special Interest following an Event of Default in accordance with this ‎Section 6.03 or the Company has elected to make such

payment but does not pay the Special Interest when due, the Notes shall be immediately subject to acceleration as provided in ‎Section 6.02.

In order to elect to pay Special Interest as the

sole remedy during the first 360 days after the occurrence of any Event of Default described in the immediately preceding paragraph,

the Company must notify all Holders of the Notes in writing and notify the Trustee and the Paying Agent in an Officers’ Certificate

(consistent with ‎Section 4.06(i)) of such election prior to the beginning of such 360-day period. Upon the failure to timely

give such notice, the Notes shall be immediately subject to acceleration as provided in ‎Section 6.02.

In no event shall any Special Interest that may

accrue at the Company’s election pursuant to this ‎Section 6.03, together with any Special Interest that may accrue in

accordance with ‎Section 4.06(d) as a result of the Company’s failure to timely file any document or report as

set forth therein, accrue at a rate in excess of 0.50% per annum on any Notes, regardless of the number of events or circumstances giving

rise to the requirement to pay such Special Interest.

Section 6.04. Payments of Notes on Default;

Suit Therefor. If an Event of Default described in clause ‎(a) or ‎(b) of ‎Section 6.01 shall have

occurred and be continuing, the Company shall, upon demand of the Trustee, pay to the Trustee, for the benefit of the Holders of the

Notes, the whole amount then due and payable on the Notes for principal and Special Interest, if any (with no interest accruing on any

overdue principal or interest, if any, unless Special Interest was payable pursuant to this Indenture on the required payment date, in

which case such overdue amounts shall accrue interest per annum at the then-applicable Special Interest rate borne by the Notes, subject

to the enforceability thereof under applicable law, from, and including, such required payment date), and, in addition thereto, such

further amount as shall be sufficient to cover any amounts due to the Trustee under ‎Section 7.06. If the Company shall fail

to pay such amounts forthwith upon such demand, the Trustee, in its own name and as trustee of an express trust, may institute a judicial

proceeding for the collection of the sums so due and unpaid, may prosecute such proceeding to judgment or final decree and may enforce

the same against the Company or any other obligor upon the Notes and collect the moneys adjudged or decreed to be payable in the manner

provided by law out of the property of the Company or any other obligor upon the Notes, wherever situated.

In the event there shall be pending proceedings

for the bankruptcy or for the reorganization of the Company or any other obligor on the Notes under Title 11 of the United States Code,

or any other applicable law, or in case a receiver, assignee or trustee in bankruptcy or reorganization, liquidator, sequestrator or

similar official shall have been appointed for or taken possession of the Company or such other obligor, the property of the Company

or such other obligor, or in the event of any other judicial proceedings relative to the Company or such other obligor upon the Notes,

or to the creditors or property of the Company or such other obligor, the Trustee, irrespective of whether the principal of the Notes

shall then be due and payable as therein expressed or by declaration or otherwise and irrespective of whether the Trustee shall have

made any demand pursuant to the provisions of this ‎Section 6.04, shall be entitled and empowered, by intervention in such

proceedings or otherwise, to file and prove a claim or claims for the whole amount of principal and accrued and unpaid Special Interest,

if any, in respect of the Notes, and, in case of any judicial proceedings, to file such proofs of claim and other papers or documents

and to take such other actions as it may deem necessary or advisable in order to have the claims of the Trustee (including any claim

for the reasonable compensation, expenses, disbursements and advances of the Trustee, its agents and counsel) and of the Holders allowed

in such judicial proceedings relative to the Company or any other obligor on the Notes, its or their creditors, or its or their property,

and to collect and receive any monies or other property payable or deliverable on any such claims, and to distribute the same after the

deduction of any amounts due to the Trustee under ‎Section 7.06; and any receiver, assignee or trustee in bankruptcy or reorganization,

liquidator, custodian or similar official is hereby authorized by each of the Holders to make such payments to the Trustee, as administrative

expenses, and, in the event that the Trustee shall consent to the making of such payments directly to the Holders, to pay to the Trustee

any amount due it for reasonable compensation, expenses, advances and disbursements, including agents and counsel fees, and including

any other amounts due to the Trustee under ‎Section 7.06, incurred by it up to the date of such distribution. To the extent

that such payment of compensation, reasonable expenses, advances and disbursements out of the estate in any such proceedings shall be

denied for any reason, payment of the same shall be secured by a lien on, and shall be paid out of, any and all distributions, dividends,

monies, securities and other property that the Holders of the Notes may be entitled to receive in such proceedings, whether in liquidation

or under any plan of reorganization or arrangement or otherwise.

Nothing herein contained shall be deemed to authorize

the Trustee to authorize or consent to or accept or adopt on behalf of any Holder any plan of reorganization, arrangement, adjustment

or composition affecting such Holder or the rights of any Holder thereof, or to authorize the Trustee to vote in respect of the claim

of any Holder in any such proceeding.

All rights of action and of asserting claims under

this Indenture, or under any of the Notes, may be enforced by the Trustee without the possession of any of the Notes, or the production

thereof at any trial or other proceeding relative thereto, and any such suit or proceeding instituted by the Trustee shall be brought

in its own name as trustee of an express trust, and any recovery of judgment shall, after provision for the payment of the reasonable

compensation, expenses, disbursements and advances of the Trustee, its agents and counsel, be for the ratable benefit of the Holders

of the Notes.

In any proceedings brought by the Trustee (and

in any proceedings involving the interpretation of any provision of this Indenture to which the Trustee shall be a party) the Trustee

shall be held to represent all the Holders of the Notes, and it shall not be necessary to make any Holders of the Notes parties to any

such proceedings.

In case the Trustee shall have proceeded to enforce

any right under this Indenture and such proceedings shall have been discontinued or abandoned because of any waiver pursuant to ‎Section 6.09

or any rescission and annulment pursuant to ‎Section 6.02 or for any other reason or shall have been determined adversely to

the Trustee, then and in every such case the Company, the Holders and the Trustee shall, subject to any determination in such proceeding,

be restored respectively to their several positions and rights hereunder, and all rights, remedies and powers of the Company, the Holders

and the Trustee shall continue as though no such proceeding had been instituted.

Section 6.05. Application of Monies Collected

by Trustee. Any monies or property collected by the Trustee pursuant to this ‎Article 6 with respect to the Notes shall

be applied in the following order, at the date or dates fixed by the Trustee for the distribution of such monies or property, upon presentation

of the several Notes, and stamping thereon the payment, if only partially paid, and upon surrender thereof, if fully paid:

First,

to the payment of all amounts due the Trustee (acting in any capacity hereunder) hereunder, including its agents and counsel, under ‎Section 7.06;

Second,

in case the principal of the outstanding Notes shall not have become due and be unpaid, to the payment of interest, if any, on, and any

cash due upon conversion of, the Notes in default in the order of the date due of the payments of such interest and cash due upon conversion,

as the case may be, with interest (to the extent that any such interest is payable on such Notes and has been collected by the Trustee)

upon such overdue payments at the rate of Special Interest then payable on such Notes, if any, such payments to be made ratably to the

Persons entitled thereto;

Third,

in case the principal of the outstanding Notes shall have become due, by declaration or otherwise, and be unpaid to the payment of the

whole amount (including, if applicable, the payment of the Redemption Price, the Fundamental Change Repurchase Price and any cash due

upon conversion) then owing and unpaid upon the Notes for principal and interest, if any, with interest (to the extent that any Special

Interest is then payable on the Notes) on the overdue principal and, to the extent that such interest, if any, has been collected by

the Trustee, upon overdue installments of interest to the extent that payment of such interest is enforceable under applicable law, at

the rate of Special Interest borne by the Notes at such time, if any, and in case such monies shall be insufficient to pay in full the

whole amounts so due and unpaid upon the Notes, then to the payment of such principal (including, if applicable, the Redemption Price

and the Fundamental Change Repurchase Price and any cash due upon conversion) and any interest without preference or priority of principal

over interest, or of any interest over principal or of any installment of interest over any other installment of interest, or of any

Note over any other Note, ratably to the aggregate of such principal (including, if applicable, the Redemption Price, the Fundamental

Change Repurchase Price and any cash due upon conversion) and any accrued and unpaid Special Interest; and

Fourth,

to the payment of the remainder, if any, to the Company.

Section 6.06. Proceedings by Holders.

Except to enforce the right to receive payment of principal (including, if applicable, the Redemption Price and the Fundamental Change

Repurchase Price) or any interest when due, or the right to receive payment or delivery of the consideration due upon conversion, no

Holder of any Note shall have any right by virtue of or by availing of any provision of this Indenture to institute any suit, action

or proceeding in equity or at law upon or under or with respect to this Indenture, or for the appointment of a receiver, trustee, liquidator,

custodian or other similar official, or for any other remedy hereunder, unless:

(a)            such

Holder previously shall have given to the Trustee written notice of an Event of Default and of the continuance thereof, as herein provided;

(b)            Holders

of at least 25% in aggregate principal amount of the Notes then outstanding shall have made written request upon the Trustee to institute

such action, suit or proceeding in its own name as Trustee hereunder;

Holders shall have offered and, if requested, provided to the Trustee such security or indemnity reasonably satisfactory to the Trustee

against any loss, liability, cost or expense to be incurred therein or thereby;

(d)            the

Trustee for 60 days after its receipt of such notice, request and offer of such security or indemnity, shall have neglected or refused

to institute any such action, suit or proceeding; and

(e)            no

direction that, in the opinion of the Trustee, is inconsistent with such written request shall have been given to the Trustee by the

Holders of a majority of the aggregate principal amount of the Notes then outstanding within such 60-day period pursuant to ‎Section 6.09,

it being understood and intended, and being expressly covenanted by

the taker and Holder of every Note with every other taker and Holder and the Trustee that no one or more Holders shall have any right

in any manner whatsoever by virtue of or by availing of any provision of this Indenture to affect, disturb or prejudice the rights of

any other Holder (it being understood that the Trustee shall not have an affirmative duty to ascertain whether or not any such direction

is unduly prejudicial to any other Holder), or to obtain or seek to obtain priority over or preference to any other such Holder, or to

enforce any right under this Indenture, except in the manner herein provided and for the equal, ratable and common benefit of all Holders

(except as otherwise provided herein). For the protection and enforcement of this ‎Section 6.06, each and every Holder and

the Trustee shall be entitled to such relief as can be given either at law or in equity.

Notwithstanding any other provision of this Indenture

and any provision of any Note, each Holder shall have the right to receive payment or delivery, as the case may be, of (x) the

principal (including the Redemption Price and the Fundamental Change Repurchase Price, if applicable) of, (y) accrued and unpaid

Special Interest, if any, on, and (z) the consideration due upon conversion of, such Note, on or after the respective due dates

expressed or provided for in such Note or in this Indenture, or to institute suit for the enforcement of any such payment or delivery,

as the case may be.

Section 6.07. Proceedings by Trustee.

In case of an Event of Default, the Trustee may in its discretion proceed to protect and enforce the rights vested in it by this Indenture

by such appropriate judicial proceedings as are necessary to protect and enforce any of such rights, either by suit in equity or by action

at law or by proceeding in bankruptcy or otherwise, whether for the specific enforcement of any covenant or agreement contained in this

Indenture or in aid of the exercise of any power granted in this Indenture, or to enforce any other legal or equitable right vested in

the Trustee by this Indenture or by law.

Section 6.08. Remedies Cumulative and

Continuing. Except as provided in the last paragraph of ‎Section 2.06, all powers and remedies given by this ‎Article 6

to the Trustee or to the Holders shall, to the extent permitted by law, be deemed cumulative and not exclusive of any thereof or of any

other powers and remedies available to the Trustee or the Holders of the Notes, by judicial proceedings or otherwise, to enforce the

performance or observance of the covenants and agreements contained in this Indenture, and no delay or omission of the Trustee or of

any Holder of any of the Notes to exercise any right or power accruing upon any Default or Event of Default shall impair any such right

or power, or shall be construed to be a waiver of any such Default or Event of Default or any acquiescence therein; and, subject to the

provisions of ‎Section 6.06, every power and remedy given by this ‎Article 6 or by law to the Trustee or to the Holders

may be exercised from time to time, and as often as shall be deemed expedient, by the Trustee or by the Holders.

Section 6.09. Direction of Proceedings

and Waiver of Defaults by Majority of Holders. Subject to the Trustee’s right to receive security or indemnity from the relevant

Holders as described herein, the Holders of a majority of the aggregate principal amount of the Notes at the time outstanding determined

in accordance with ‎Section 8.04 shall have the right to direct the time, method and place of conducting any proceeding for

any remedy available to the Trustee or exercising any trust or power conferred on the Trustee with respect to the Notes; provided,

however, that (a) such direction shall not be in conflict with any rule of law or with this Indenture, and (b) the

Trustee may take any other action deemed proper by the Trustee that is not inconsistent with such direction. The Trustee may refuse to

follow any direction that it determines is in conflict with any rule of law or with this Indenture or is unduly prejudicial to

the rights of any other Holder or that would involve the Trustee in personal liability (it being understood that the Trustee shall not

have an affirmative duty to ascertain whether or not any such direction is unduly prejudicial to any other Holder) or for which it has

not received indemnity or security satisfactory to the Trustee against any loss, liability or expense. The Holders of a majority in aggregate

principal amount of the Notes at the time outstanding determined in accordance with ‎Section 8.04 may on behalf of the Holders

of all of the Notes waive any past Default or Event of Default hereunder and its consequences except (i) a continuing default in

the payment of accrued and unpaid Special Interest, if any, on, or the principal (including any Redemption Price and any Fundamental

Change Repurchase Price) of, the Notes when due that has not been cured pursuant to the provisions of ‎Section 6.01, (ii) a

continuing failure by the Company to pay or deliver, as the case may be, the consideration due upon conversion of the Notes or (iii) a

continuing default in respect of a covenant or provision hereof which under ‎Article 10 cannot be modified or amended without

the consent of each Holder of an outstanding Note affected. Upon any such waiver the Company, the Trustee and the Holders of the Notes

shall be restored to their former positions and rights hereunder; but no such waiver shall extend to any subsequent or other Default

or Event of Default or impair any right consequent thereon. Whenever any Default or Event of Default hereunder shall have been waived

as permitted by this ‎Section 6.09, said Default or Event of Default shall for all purposes of the Notes and this Indenture

be deemed to have been cured and to be not continuing; but no such waiver shall extend to any subsequent or other Default or Event of

Default or impair any right consequent thereon.

Section 6.10. Notice of Defaults.

The Trustee shall, within 90 days after a Responsible Officer obtains actual knowledge of the occurrence and continuance of a Default,

deliver to all Holders notice of all Defaults actually known to a Responsible Officer, unless such Defaults shall have been cured or

waived before the giving of such notice; provided that, except in the case of a Default in the payment of the principal of (including

the Redemption Price and the Fundamental Change Repurchase Price, if applicable), or any accrued and unpaid Special Interest on, any

of the Notes or a Default in the payment or delivery of the consideration due upon conversion, the Trustee shall be protected in withholding

such notice if and so long as a Responsible Officer of the Trustee in good faith determines that the withholding of such notice is in

the interests of the Holders.

Section 6.11. Undertaking to Pay Costs.

All parties to this Indenture agree, and each Holder of any Note by its acceptance thereof shall be deemed to have agreed, that any court

may, in its discretion, require, in any suit for the enforcement of any right or remedy under this Indenture, or in any suit against

the Trustee for any action taken or omitted by it as Trustee, the filing by any party litigant in such suit of an undertaking to pay

the costs of such suit and that such court may in its discretion assess reasonable costs, including reasonable attorneys’ fees

and expenses, against any party litigant in such suit, having due regard to the merits and good faith of the claims or defenses made

by such party litigant; provided that the provisions of this ‎Section 6.11 (to the extent permitted by law) shall not

apply to any suit instituted by the Trustee, to any suit instituted by any Holder, or group of Holders, holding in the aggregate more

than 10% in principal amount of the Notes at the time outstanding determined in accordance with ‎Section 8.04, or to any suit

instituted by any Holder for the enforcement of the payment of the principal of or accrued and unpaid Special Interest, if any, on any

Note (including, but not limited to, the Redemption Price and the Fundamental Change Repurchase Price, if applicable, with respect to

the Notes being redeemed or repurchased upon a Fundamental Change, as applicable, as provided in this Indenture) on or after the due

date expressed or provided for in such Note or to any suit for the enforcement of the right to convert any Note, or receive the consideration

due upon conversion, in accordance with the provisions of ‎Article 14.

Article 7

Concerning the Trustee

Section 7.01. Duties and Responsibilities

of Trustee. The Trustee, prior to the occurrence of an Event of Default and after the curing or waiver of all Events of Default that

may have occurred, undertakes to perform such duties and only such duties as are specifically set forth in this Indenture. In the event

an Event of Default has occurred and is continuing and is known to a Responsible Officer, the Trustee shall exercise such of the rights

and powers vested in it by this Indenture, and use the same degree of care and skill in its exercise, as a prudent person would exercise

or use under the circumstances in the conduct of such person’s own affairs under the circumstances; provided that if an

Event of Default occurs and is continuing, the Trustee will be under no obligation to exercise any of the rights or powers under this

Indenture at the request or direction of any of the Holders unless such Holders have offered to, and, if requested, provided to the Trustee

indemnity or security satisfactory to the Trustee against any loss, liability, cost or expense that might be incurred by it in compliance

with such request or direction.

No provision of this Indenture shall be construed

to relieve the Trustee from liability for its own grossly negligent action, its own grossly negligent failure to act or its own willful

misconduct, except that:

(a)            prior

to the occurrence of an Event of Default and after the curing or waiving of all Events of Default that may have occurred:

(i)            the

duties and obligations of the Trustee shall be determined solely by the express provisions of this Indenture, and the Trustee shall not

be liable except for the performance of such duties and obligations as are specifically set forth in this Indenture and no implied covenants

or obligations shall be read into this Indenture against the Trustee; and

(ii)            in

the absence of gross negligence or willful misconduct on the part of the Trustee, the Trustee may conclusively rely, as to the truth

of the statements and the correctness of the opinions expressed therein, upon any certificates or opinions furnished to the Trustee and

conforming to the requirements of this Indenture; but, in the case of any such certificates or opinions that by any provisions hereof

are specifically required to be furnished to the Trustee, the Trustee shall be under a duty to examine the same to determine whether

or not they conform to the requirements of this Indenture (but need not confirm or investigate the accuracy of any mathematical calculations

or other facts stated therein);

(b)            the

Trustee shall not be liable for any action taken or error of judgment made in good faith by a Responsible Officer or Officers of the

Trustee, unless it shall be proved that the Trustee was grossly negligent in ascertaining the pertinent facts;

Trustee shall not be liable with respect to any action taken or omitted to be taken by it in good faith in accordance with the direction

of the Holders of not less than a majority of the aggregate principal amount of the Notes at the time outstanding determined as provided

in ‎Section 8.04 relating to the time, method and place of conducting any proceeding for any remedy available to the Trustee,

or exercising any trust or power conferred upon the Trustee, under this Indenture;

(d)            whether

or not therein provided, every provision of this Indenture relating to the conduct or affecting the liability of, or affording protection

to, the Trustee shall be subject to the provisions of this Section and ‎Section 7.02;

(e)            the

Trustee shall not be liable in respect of any payment (as to the correctness of amount, entitlement to receive or any other matters relating

to payment) or notice effected by the Company or any Paying Agent or any records maintained by any co-Note Registrar with respect to

the Notes;

(f)            if

any party fails to deliver a notice relating to an event the fact of which, pursuant to this Indenture, requires notice to be sent to

the Trustee, the Trustee may conclusively rely on its failure to receive such notice as reason to act as if no such event occurred, unless

a Responsible Officer of the Trustee had actual knowledge of such event;

(g)            in

the absence of written investment direction from the Company, all cash received by the Trustee shall be placed in a non-interest bearing

trust account, and in no event shall the Trustee be liable for the selection of investments or for investment losses incurred thereon

or for losses incurred as a result of the liquidation of any such investment prior to its maturity date or the failure of the party directing

such investments prior to its maturity date or the failure of the party directing such investment to provide timely written investment

direction, and the Trustee shall have no obligation to invest or reinvest any amounts held hereunder in the absence of such written investment

direction from the Company; and

(h)            in

the event that the Trustee is also acting as Custodian, Note Registrar, Paying Agent, Conversion Agent, Bid Solicitation Agent or transfer

agent hereunder, the rights and protections afforded to the Trustee pursuant to this ‎Article 7 shall also be afforded to such

Custodian, Note Registrar, Paying Agent, Conversion Agent, Bid Solicitation Agent or transfer agent.

None of the provisions contained in this Indenture

or the Notes shall require the Trustee to expend or risk its own funds or otherwise incur personal financial liability in the performance

of any of its duties or in the exercise of any of its rights or powers.

Section 7.02. Reliance on Documents,

Opinions, Etc. Except as otherwise provided in ‎Section 7.01:

(a)            the

Trustee may conclusively rely and shall be fully protected in acting upon any resolution, certificate, statement, instrument, opinion,

report, notice, request, consent, order, bond, note, coupon or other paper or document (whether in its original or facsimile form) believed

by it in good faith to be genuine and to have been signed or presented by the proper party or parties;

(b)            any

request, direction, order or demand of the Company mentioned herein shall be sufficiently evidenced by an Officers’ Certificate

(unless other evidence in respect thereof be herein specifically prescribed); and any Board Resolution may be evidenced to the Trustee

by a copy thereof certified by the Secretary or an Assistant Secretary of the Company, and the Trustee will not be liable for any action

it takes or omits to take in good faith reliance on such Officers’ Certificate;

Trustee may consult with counsel and may require an Officers’ Certificate or Opinion of Counsel and any advice of such counsel,

Officers’ Certificate or Opinion of Counsel shall be full and complete authorization and protection in respect of any action taken

or omitted by it hereunder in good faith and in accordance with such advice or Officers’ Certificate or Opinion of Counsel;

(d)            the

Trustee shall not be bound to make any investigation into the facts or matters stated in any resolution, certificate, statement, instrument,

opinion, report, notice, request, direction, consent, order, bond, debenture or other paper or document, but the Trustee, in its discretion,

may make such further inquiry or investigation into such facts or matters as it may see fit, and, if the Trustee shall determine in its

reasonable judgment to make such further inquiry or investigation, it shall be entitled, at a reasonable time on any Business Day after

reasonable notice, to examine the books, records and premises of the Company, personally or by agent or attorney at the expense of the

Company and shall incur no liability of any kind by reason of such inquiry or investigation;

(e)            the

Trustee may execute any of the trusts or powers hereunder or perform any duties hereunder either directly or by or through agents, custodians,

nominees or attorneys and the Trustee shall not be responsible for any action, inaction, misconduct or negligence on the part of any

agent, custodian, nominee or attorney appointed by it with due care hereunder;

(f)            the

rights, privileges, protections, immunities and benefits given to the Trustee, including, without limitation, its right to be indemnified,

are extended to, and shall be enforceable by, the Trustee in each of its capacities hereunder, and each agent, Custodian or other Person

employed to act hereunder;

(g)            the

permissive rights of the Trustee enumerated herein shall not be construed as duties;

(h)            the

Trustee shall not be required to give any bond or surety in respect of the execution of the trusts and powers under this Indenture; under

no circumstances shall the Trustee be liable in its individual capacity for the obligations evidenced by the Notes; the Trustee may request

that the Company deliver an Officers’ Certificate setting forth the names of individuals and the titles of officers authorized

at such time to take specified actions pursuant to this Indenture, which Officers’ Certificate may be signed by any Person authorized

to sign an Officers’ Certificate, including any Person specified as so authorized in any such certificate previously delivered

and not superseded;

(i)            the

Trustee shall have no obligation to pursue any action that is not in accordance with applicable law;

(j)            the

Trustee shall be under no obligation to exercise any of the rights or powers vested in it by this Indenture at the request or direction

of any of the Holders pursuant to this Indenture, unless such Holders shall have offered (and if requested, provided) to the Trustee

security or indemnity satisfactory to the Trustee against the costs, expenses and liabilities which might be incurred by it in compliance

with such request or direction; and

(k)            the

Trustee shall not be liable for any action taken, suffered, or omitted to be taken by it in good faith and reasonably believed by it

to be authorized or within the discretion or rights or powers conferred upon it by this Indenture.

In no event shall the Trustee be responsible or

liable for any punitive, special, indirect or consequential loss or damage of any kind whatsoever (including but not limited to lost

profits), even if the Trustee has been advised of the likelihood of such loss or damage and regardless of the form of action. The Trustee

shall not be charged with knowledge of (or be required to act including the sending of any notices with respect to) any Default or Event

of Default with respect to the Notes, unless either (1) a Responsible Officer shall have actual knowledge of such Default or Event

of Default or (2) written notice of such Default or Event of Default shall have been actually received by a Responsible Officer

of the Trustee, subject to the terms hereof.

Section 7.03. No Responsibility for Recitals,

Etc. The recitals contained herein and in the Notes (except in the Trustee’s certificate of authentication) shall be taken

as the statements of the Company, and the Trustee assumes no responsibility for the correctness of the same. The Trustee makes no representations

as to the validity or sufficiency of this Indenture or of the Notes or the Common Stock (or other Reference Property) underlying the

Notes. The Trustee shall not be accountable for the use or application by the Company of any Notes or the proceeds of any Notes authenticated

and delivered by the Trustee in conformity with the provisions of this Indenture or any money paid to the Company or upon the Company’s

direction under any provision of the Indenture. The Trustee shall have no responsibility or liability with respect to any information,

statement or recital in the Offering Memorandum or other disclosure material prepared or distributed with respect to the issuance of

the Notes.

Section 7.04. Trustee, Paying Agents,

Conversion Agents, Bid Solicitation Agent or Note Registrar May Own Notes. The Trustee, any Paying Agent, any Conversion Agent,

Bid Solicitation Agent (if other than the Company or any Affiliate thereof) or Note Registrar, in its individual or any other capacity,

may become the owner or pledgee of Notes with the same rights it would have if it were not the Trustee, Paying Agent, Conversion Agent,

Bid Solicitation Agent or Note Registrar.

Section 7.05. Monies and Shares of Common

Stock to Be Held in Trust. All monies and shares of Common Stock received by the Trustee shall, until used or applied as herein provided,

be held in trust for the purposes for which they were received. Money and shares of Common Stock held by the Trustee in trust hereunder

need not be segregated from other funds except to the extent required by law. The Trustee shall be under no liability for interest on

any money or shares of Common Stock received by it hereunder except as may be agreed to in writing from time to time by the Company and

the Trustee.

Section 7.06. Compensation and Expenses

of Trustee. The Company covenants and agrees to pay to the Trustee, in each capacity under this Indenture, from time to time, and

the Trustee shall be entitled to, compensation for all services rendered by it hereunder in any capacity (which shall not be limited

by any provision of law in regard to the compensation of a trustee of an express trust) as mutually agreed to in writing between the

Trustee and the Company, and the Company will pay or reimburse the Trustee upon its request for all reasonable fees, costs, expenses,

disbursements and advances reasonably incurred or made by the Trustee in accordance with any of the provisions of this Indenture in any

capacity thereunder (including the compensation and the reasonable expenses and disbursements of its agents and counsel and of all Persons

not regularly in its employ) except any such expense, disbursement or advance as shall have been caused by its gross negligence or willful

misconduct as adjudicated by a court of competent jurisdiction. The Company also covenants to indemnify the Trustee in any capacity under

this Indenture and any other document or transaction entered into in connection herewith and its agents and any authenticating agent

for, and to hold them harmless against, any loss, claim, damage, liability, cost, fees or expense (including attorneys’ fees and

expenses and court costs) incurred without gross negligence or willful misconduct, as adjudicated by a court of competent jurisdiction,

on the part of the Trustee, its officers, directors, agents or employees, or such agent or authenticating agent, as the case may be,

and arising out of or in connection with the acceptance or administration of this Indenture or in any other capacity hereunder (whether

the claims arise by or against the Company or a third person), including the costs and expenses of defending themselves against any claim

of liability (including attorneys’ fees and expenses and court costs) in the premises or enforcing the Company’s obligations,

including the Trustee’s right to indemnity, hereunder. The obligations of the Company under this ‎Section 7.06 to compensate

or indemnify the Trustee and to pay or reimburse the Trustee for expenses, disbursements and advances shall be secured by a senior lien

to which the Notes are hereby made subordinate on all money or property held or collected by the Trustee, except, subject to the effect

of ‎Section 6.05, funds held in trust herewith for the benefit of the Holders of particular Notes, and, for the avoidance of

doubt, such lien shall not be extended in a manner that would conflict with the Company’s obligations to its other creditors. The

Trustee’s right to receive payment of any amounts due under this ‎Section 7.06 shall not be subordinate to any other

liability or indebtedness of the Company. The obligations of the Company under Article 7 shall survive the satisfaction and discharge

of this Indenture and the earlier resignation or removal of the Trustee. The Company need not pay for any settlement made without its

consent, which consent shall not be unreasonably withheld. The indemnification provided in this ‎Section 7.06 shall extend

to the officers, directors, agents and employees of the Trustee.

Without prejudice to any other rights available

to the Trustee under applicable law, when the Trustee and its agents and any authenticating agent incur expenses or render services after

an Event of Default specified in ‎Section 6.01(h) or ‎Section 6.01(i) occurs, the expenses and the compensation

for the services are intended to constitute expenses of administration under any bankruptcy, insolvency or similar laws.

Section 7.07. Officers’ Certificate

as Evidence. Except as otherwise provided in ‎Section 7.01, whenever in the administration of the provisions of this Indenture

the Trustee shall deem it necessary or desirable that a matter be proved or established prior to taking or omitting any action hereunder,

such matter (unless other evidence in respect thereof be herein specifically prescribed) may, in the absence of gross negligence or willful

misconduct, on the part of the Trustee, be deemed to be conclusively proved and established by an Officers’ Certificate delivered

to the Trustee, and such Officers’ Certificate, in the absence of gross negligence or willful misconduct on the part of the Trustee,

shall be full warrant to the Trustee for any action taken or omitted by it under the provisions of this Indenture upon the faith thereof.

Section 7.08. Eligibility of Trustee.

There shall at all times be a Trustee hereunder which shall be a Person that is eligible pursuant to the Trust Indenture Act (as if the

Trust Indenture Act were applicable hereto) to act as such and has a combined capital and surplus of at least $50,000,000. If such Person

publishes reports of condition at least annually, pursuant to law or to the requirements of any supervising or examining authority, then

for the purposes of this Section, the combined capital and surplus of such Person shall be deemed to be its combined capital and surplus

as set forth in its most recent report of condition so published. If at any time the Trustee shall cease to be eligible in accordance

with the provisions of this Section, it shall resign immediately in the manner and with the effect hereinafter specified in this Article.

Section 7.09. Resignation or Removal

of Trustee. (a) The Trustee may at any time resign by giving written notice of such resignation to the Company and by delivering

notice thereof to the Holders. Upon receiving such notice of resignation, the Company shall promptly appoint a successor trustee by written

instrument, in duplicate, executed by order of the Board of Directors, one copy of which instrument shall be delivered to the resigning

Trustee and one copy to the successor trustee. If no successor trustee shall have been so appointed and have accepted appointment within

60 days after the giving of such notice of resignation to the Holders, the resigning Trustee may, at the expense of the Company, upon

ten Business Days’ notice to the Company and the Holders, petition any court of competent jurisdiction for the appointment of a

successor trustee, or any Holder who has been a bona fide holder of a Note or Notes for at least six months (or since the date of this

Indenture) may, subject to the provisions of ‎Section 6.11, on behalf of himself or herself and all others similarly situated,

petition any such court for the appointment of a successor trustee. Such court may thereupon, after such notice, if any, as it may deem

proper and prescribe, appoint a successor trustee.

(b)            In

case at any time any of the following shall occur:

(i)            the

Trustee shall cease to be eligible in accordance with the provisions of ‎Section 7.08 and shall fail to resign after written

request therefor by the Company or by any such Holder, or

(ii)            the

Trustee shall become incapable of acting, or shall be adjudged a bankrupt or insolvent, or a receiver of the Trustee or of its property

shall be appointed, or any public officer shall take charge or control of the Trustee or of its property or affairs for the purpose of

rehabilitation, conservation or liquidation,

then, in either case, the Company may by a Board Resolution remove

the Trustee and appoint a successor trustee by written instrument, in duplicate, executed by order of the Board of Directors, one copy

of which instrument shall be delivered to the Trustee so removed and one copy to the successor trustee, or, subject to the provisions

of ‎Section 6.11, any Holder who has been a bona fide holder of a Note or Notes for at least six months (or since the date

of this Indenture) may, on behalf of himself or herself and all others similarly situated, petition any court of competent jurisdiction

for the removal of the Trustee and the appointment of a successor trustee. Such court may thereupon, after such notice, if any, as it

may deem proper and prescribe, remove the Trustee and appoint a successor trustee.

Holders of a majority in aggregate principal amount of the Notes at the time outstanding, as determined in accordance with ‎Section 8.04,

may at any time remove the Trustee upon 30 days’ advance written notice to the Trustee and the Company and nominate a successor

trustee that shall be deemed appointed as successor trustee unless within ten days after notice to the Company of such nomination the

Company objects thereto, in which case the Trustee so removed or any Holder, upon the terms and conditions and otherwise as in ‎Section 7.09(a) provided,

may petition any court of competent jurisdiction for an appointment of a successor trustee.

(d)            Any

resignation or removal of the Trustee and appointment of a successor trustee pursuant to any of the provisions of this ‎Section 7.09

shall become effective upon acceptance of appointment by the successor trustee as provided in ‎Section 7.10.

Section 7.10. Acceptance by Successor

Trustee. Any successor trustee appointed as provided in ‎Section 7.09 shall execute, acknowledge and deliver to the Company

and to its predecessor trustee an instrument accepting such appointment hereunder, and thereupon the resignation or removal of the predecessor

trustee shall become effective and such successor trustee, without any further act, deed or conveyance, shall become vested with all

the rights, powers, duties and obligations of its predecessor hereunder, with like effect as if originally named as Trustee herein; but,

nevertheless, on the written request of the Company or of the successor trustee, the trustee ceasing to act shall, upon payment of any

amounts then due it pursuant to the provisions of ‎Section 7.06, execute and deliver an instrument transferring to such successor

trustee all the rights and powers of the trustee so ceasing to act. Upon request of any such successor trustee, the Company shall execute

any and all instruments in writing for more fully and certainly vesting in and confirming to such successor trustee all such rights and

powers. Any trustee ceasing to act shall, nevertheless, retain a senior lien to which the Notes are hereby made subordinate on all money

or property held or collected by such trustee as such, except for funds held in trust for the benefit of Holders of particular Notes,

to secure any amounts then due it pursuant to the provisions of ‎Section 7.06.

No successor trustee shall accept appointment

as provided in this ‎Section 7.10 unless at the time of such acceptance such successor trustee shall be eligible under the

provisions of ‎Section 7.08.

Upon acceptance of appointment by a successor

trustee as provided in this ‎Section 7.10, each of the Company and the successor trustee, at the written direction and at the

expense of the Company shall deliver or cause to be delivered notice of the succession of such trustee hereunder to the Holders. If the

Company fails to deliver such notice within ten days after acceptance of appointment by the successor trustee, the successor trustee

shall cause such notice to be delivered at the expense of the Company.

Section 7.11. Succession by Merger, Etc.

Any corporation or other entity into which the Trustee may be merged or converted or with which it may be consolidated, or any corporation

or other entity resulting from any merger, conversion or consolidation to which the Trustee shall be a party, or any corporation or other

entity succeeding to all or substantially all of the corporate trust business of the Trustee (including the administration of this Indenture),

shall be the successor to the Trustee hereunder without the execution or filing of any paper or any further act on the part of any of

the parties hereto; provided that in the case of any corporation or other entity succeeding to all or substantially all of the

corporate trust business of the Trustee such corporation or other entity shall be eligible under the provisions of ‎Section 7.08.

In case at the time such successor to the Trustee

shall succeed to the trusts created by this Indenture, any of the Notes shall have been authenticated but not delivered, any such successor

to the Trustee may adopt the certificate of authentication of any predecessor trustee or authenticating agent appointed by such predecessor

trustee, and deliver such Notes so authenticated; and in case at that time any of the Notes shall not have been authenticated, any successor

to the Trustee or an authenticating agent appointed by such successor trustee may authenticate such Notes either in the name of any predecessor

trustee hereunder or in the name of the successor trustee; and in all such cases such certificates shall have the full force which it

is anywhere in the Notes or in this Indenture provided that the certificate of the Trustee shall have; provided, however,

that the right to adopt the certificate of authentication of any predecessor trustee or to authenticate Notes in the name of any predecessor

trustee shall apply only to its successor or successors by merger, conversion or consolidation.

Section 7.12. Trustee’s Application

for Instructions from the Company. Any application by the Trustee for written instructions from the Company (other than with regard

to any action proposed to be taken or omitted to be taken by the Trustee that affects the rights of the Holders of the Notes under this

Indenture) may, at the option of the Trustee, set forth in writing any action proposed to be taken or omitted by the Trustee under this

Indenture and the date on and/or after which such action shall be taken or such omission shall be effective. The Trustee shall not be

liable to the Company for any action taken by, or omission of, the Trustee in accordance with a proposal included in such application

on or after the date specified in such application (which date shall not be less than three Business Days after the date notice to the

Company is deemed to be received pursuant to Section 17.03, unless any such officer shall have consented in writing to any earlier

date), unless, prior to taking any such action (or the effective date in the case of any omission), the Trustee shall have received written

instructions in accordance with this Indenture in response to such application specifying the action to be taken or omitted.

Article 8

Concerning the Holders

Section 8.01. Action by Holders.

Whenever in this Indenture it is provided that the Holders of a specified percentage of the aggregate principal amount of the Notes may

take any action (including the making of any demand or request, the giving of any notice, consent or waiver or the taking of any other

action), the fact that at the time of taking any such action, the Holders of such specified percentage have joined therein may be evidenced

(a) by any instrument or any number of instruments of similar tenor executed by Holders in person or by agent or proxy appointed

in writing, or (b) by the record of the Holders voting in favor thereof at any meeting of Holders duly called and held in accordance

with the provisions of ‎Article 9, or (c) by a combination of such instrument or instruments and any such record of such

a meeting of Holders. Whenever the Company or the Trustee solicits the taking of any action by the Holders of the Notes, the Company

or the Trustee may, but shall not be required to, fix in advance of such solicitation, a date as the record date for determining Holders

entitled to take such action. The record date if one is selected shall be not more than fifteen days prior to the date of commencement

of solicitation of such action.

Section 8.02. Proof of Execution by Holders.

Subject to the provisions of ‎Section 7.01, ‎Section 7.02 and ‎Section 9.05, proof of the execution of

any instrument by a Holder or its agent or proxy shall be sufficient if made in accordance with such reasonable rules and regulations

as may be prescribed by the Trustee or in such manner as shall be satisfactory to the Trustee. The holding of Notes shall be proved by

the Note Register or by a certificate of the Note Registrar. The record of any Holders’ meeting shall be proved in the manner provided

in ‎Section 9.06.

Section 8.03. Who Are Deemed Absolute

Owners. The Company, the Trustee, any authenticating agent, any Paying Agent, any Conversion Agent and any Note Registrar may deem

the Person in whose name a Note shall be registered upon the Note Register to be, and may treat it as, the absolute owner of such Note

(whether or not such Note shall be overdue and notwithstanding any notation of ownership or other writing thereon made by any Person

other than the Company or any Note Registrar) for the purpose of receiving payment of or on account of the principal (including any Redemption

Price and any Fundamental Change Repurchase Price) of and (subject to ‎Section 2.03) accrued and unpaid Special Interest, if

any, on such Note, for conversion of such Note and for all other purposes; and neither the Company nor the Trustee nor any Paying Agent

nor any Conversion Agent nor any Note Registrar shall be affected by any notice to the contrary. The sole registered Holder of a Global

Note shall be the Depositary or its nominee. All such payments or deliveries so made to any Holder for the time being, or upon its order,

shall be valid, and, to the extent of the sums or shares of Common Stock so paid or delivered, effectual to satisfy and discharge the

liability for monies payable or shares deliverable upon any such Note. Notwithstanding anything to the contrary in this Indenture or

the Notes following an Event of Default, any holder of a beneficial interest in a Global Note may directly enforce against the Company,

without the consent, solicitation, proxy, authorization or any other action of the Depositary or any other Person, such holder’s

right to exchange such beneficial interest for a Note in certificated form in accordance with the provisions of this Indenture.

Section 8.04. Company-Owned Notes Disregarded.

In determining whether the Holders of the requisite aggregate principal amount of Notes have concurred in any direction, consent, waiver

or other action under this Indenture, Notes that are owned by the Company, by any Subsidiary thereof or by any Affiliate of the Company

or any Subsidiary thereof shall be disregarded and deemed not to be outstanding for the purpose of any such determination; provided

that for the purposes of determining whether the Trustee shall be protected in relying on any such direction, consent, waiver or other

action, only Notes that a Responsible Officer actually knows are so owned shall be so disregarded. Notes so owned that have been pledged

in good faith may be regarded as outstanding for the purposes of this ‎Section 8.04 if the pledgee shall establish to the satisfaction

of the Trustee the pledgee’s right to so act with respect to such Notes and that the pledgee is not the Company, a Subsidiary thereof

or an Affiliate of the Company or a Subsidiary thereof. In the case of a dispute as to such right, any decision or indecision by the

Trustee taken upon the advice of counsel shall be full protection to the Trustee. Upon request of the Trustee, the Company shall furnish

to the Trustee promptly an Officers’ Certificate listing and identifying all Notes, if any, known by the Company to be owned or

held by or for the account of any of the above described Persons; and, subject to ‎Section 7.01, the Trustee shall be entitled

to accept such Officers’ Certificate as conclusive evidence of the facts therein set forth and of the fact that all Notes not listed

therein are outstanding for the purpose of any such determination.

Section 8.05. Revocation of Consents;

Future Holders Bound. At any time prior to (but not after) the evidencing to the Trustee, as provided in ‎Section 8.01,

of the taking of any action by the Holders of the percentage of the aggregate principal amount of the Notes specified in this Indenture

in connection with such action, any Holder of a Note that is shown by the evidence to be included in the Notes the Holders of which have

consented to such action may, by filing written notice with the Trustee at its Corporate Trust Office and upon proof of holding as provided

in ‎Section 8.02, revoke such action so far as concerns such Note. Except as aforesaid, any such action taken by the Holder

of any Note shall be conclusive and binding upon such Holder and upon all future Holders and owners of such Note and of any Notes issued

in exchange or substitution therefor or upon registration of transfer thereof, irrespective of whether any notation in regard thereto

is made upon such Note or any Note issued in exchange or substitution therefor or upon registration of transfer thereof.

Article 9

Holders’ Meetings

Section 9.01. Purpose of Meetings.

A meeting of Holders may be called at any time and from time to time pursuant to the provisions of this ‎Article 9 for any

of the following purposes:

(a)            to

give any notice to the Company or to the Trustee or to give any directions to the Trustee permitted under this Indenture, or to consent

to the waiving of any Default or Event of Default hereunder (in each case, as permitted under this Indenture) and its consequences, or

to take any other action authorized to be taken by Holders pursuant to any of the provisions of ‎Article 6;

(b)            to

remove the Trustee and nominate a successor trustee pursuant to the provisions of ‎Article 7;

consent to the execution of an indenture or indentures supplemental hereto pursuant to the provisions of ‎Section 10.02; or

(d)            to

take any other action authorized to be taken by or on behalf of the Holders of any specified aggregate principal amount of the Notes

under any other provision of this Indenture or under applicable law.

Section 9.02. Call of Meetings by Trustee.

The Trustee may at any time call a meeting of Holders to take any action specified in ‎Section 9.01, to be held at such time

and at such place as the Trustee shall determine. Notice of every meeting of the Holders, setting forth the time and the place of such

meeting and in general terms the action proposed to be taken at such meeting and the establishment of any record date pursuant to ‎Section 8.01,

shall be delivered to Holders of such Notes. Such notice shall also be delivered to the Company. Such notices shall be delivered not

less than 20 nor more than 90 days prior to the date fixed for the meeting.

Any meeting of Holders shall be valid without

notice if the Holders of all Notes then outstanding are present in person or by proxy or if notice is waived before or after the meeting

by the Holders of all Notes then outstanding, and if the Company and the Trustee are either present by duly authorized representatives

or have, before or after the meeting, waived notice.

Section 9.03. Call of Meetings by Company

or Holders. In case at any time the Company, pursuant to a Board Resolution, or the Holders of at least 10% of the aggregate principal

amount of the Notes then outstanding, shall have requested the Trustee to call a meeting of Holders, by written request setting forth

in reasonable detail the action proposed to be taken at the meeting, and the Trustee shall not have delivered the notice of such meeting

within 20 days after receipt of such request, then the Company or such Holders may determine the time and the place for such meeting

and may call such meeting to take any action authorized in ‎Section 9.01, by delivering notice thereof as provided in ‎Section 9.02.

Section 9.04. Qualifications for Voting.

To be entitled to vote at any meeting of Holders a Person shall (a) be a Holder of one or more Notes on the record date pertaining

to such meeting or (b) be a Person appointed by an instrument in writing as proxy by a Holder of one or more Notes on the record

date pertaining to such meeting. The only Persons who shall be entitled to be present or to speak at any meeting of Holders shall be

the Persons entitled to vote at such meeting and their counsel and any representatives of the Trustee and its counsel and any representatives

of the Company and its counsel.

Section 9.05. Regulations. Notwithstanding

any other provisions of this Indenture, the Trustee may make such reasonable regulations as it may deem advisable for any meeting of

Holders, in regard to proof of the holding of Notes and of the appointment of proxies, and in regard to the appointment and duties of

inspectors of votes, the submission and examination of proxies, certificates and other evidence of the right to vote, and such other

matters concerning the conduct of the meeting as it shall think fit.

The Trustee shall, by an instrument in writing,

appoint a temporary chairman of the meeting, unless the meeting shall have been called by the Company or by Holders as provided in ‎Section 9.03,

in which case the Company or the Holders calling the meeting, as the case may be, shall in like manner appoint a temporary chairman.

A permanent chairman and a permanent secretary of the meeting shall be elected by vote of the Holders of a majority in aggregate principal

amount of the Notes represented at the meeting and entitled to vote at the meeting.

Subject to the provisions of ‎Section 8.04,

at any meeting of Holders each Holder or proxyholder shall be entitled to one vote for each $1,000 principal amount of Notes held or

represented by him or her; provided, however, that no vote shall be cast or counted at any meeting in respect of any Note

challenged as not outstanding and ruled by the chairman of the meeting to be not outstanding. The chairman of the meeting shall have

no right to vote other than by virtue of Notes held by it or instruments in writing as aforesaid duly designating it as the proxy to

vote on behalf of other Holders. Any meeting of Holders duly called pursuant to the provisions of ‎Section 9.02 or ‎Section 9.03

may be adjourned from time to time by the Holders of a majority of the aggregate principal amount of Notes represented at the meeting,

whether or not constituting a quorum, and the meeting may be held as so adjourned without further notice.

Section 9.06. Voting. The vote upon

any resolution submitted to any meeting of Holders shall be by written ballot on which shall be subscribed the signatures of the Holders

or of their representatives by proxy and the outstanding aggregate principal amount of the Notes held or represented by them. The permanent

chairman of the meeting shall appoint two inspectors of votes who shall count all votes cast at the meeting for or against any resolution

and who shall make and file with the secretary of the meeting their verified written reports in duplicate of all votes cast at the meeting.

A record in duplicate of the proceedings of each meeting of Holders shall be prepared by the secretary of the meeting and there shall

be attached to said record the original reports of the inspectors of votes on any vote by ballot taken thereat and affidavits by one

or more Persons having knowledge of the facts setting forth a copy of the notice of the meeting and showing that said notice was delivered

as provided in ‎Section 9.02. The record shall show the aggregate principal amount of the Notes voting in favor of or against

any resolution. The record shall be signed and verified by the affidavits of the permanent chairman and secretary of the meeting and

one of the duplicates shall be delivered to the Company and the other to the Trustee to be preserved by the Trustee, the latter to have

attached thereto the ballots voted at the meeting.

Any record so signed and verified shall be conclusive

evidence of the matters therein stated.

Section 9.07. No Delay of Rights by Meeting.

Nothing contained in this ‎Article 9 shall be deemed or construed to authorize or permit, by reason of any call of a meeting

of Holders or any rights expressly or impliedly conferred hereunder to make such call, any hindrance or delay in the exercise of any

right or rights conferred upon or reserved to the Trustee or to the Holders under any of the provisions of this Indenture or of the Notes.

Article 10

Supplemental Indentures

Section 10.01. Supplemental Indentures

Without Consent of Holders. The Company and the Trustee, at the Company’s expense, may from time to time and at any time enter

into an indenture or indentures supplemental hereto for one or more of the following purposes:

(a)            to

cure any ambiguity, omission, defect or inconsistency, as evidenced to the Trustee in an Officers’ Certificate;

(b)            to

provide for the assumption by a Successor Company of the obligations of the Company under this Indenture and the Notes pursuant to ‎Article 11;

add guarantees with respect to the Notes;

(d)            to

secure the Notes;

(e)            to

add to the covenants or Events of Default of the Company for the benefit of the Holders or surrender any right or power conferred upon

the Company;

(f)            to

make any change that does not adversely affect the rights of any Holder;

(g)            to

increase the Conversion Rate as provided in this Indenture;

(h)            to

irrevocably elect a Settlement Method and/or Specified Dollar Amount (or a minimum Specified Dollar Amount) or eliminate the Company’s

right to elect a Settlement Method;

(i)            in

connection with any Share Exchange Event, to provide that the Notes are convertible into Reference Property, subject to the provisions

of ‎Section 14.02, and make such related changes to the terms of the Notes to the extent expressly required by ‎Section 14.07;

(j)            to

appoint a successor trustee or facilitate the administration of the trusts under this Indenture by more than one trustee, in each case,

with respect to the Notes;

(k)            to

comply with the rules of any applicable securities depositary in a manner that does not adversely affect the rights of any Holder;

(l)            to

conform the provisions of this Indenture or the Notes to any provision of the “Description of Notes” section of the Offering

Memorandum; or

(m)            provide

for the issuance of additional Notes in accordance with this Indenture.

Upon the written request of the Company, the Trustee

is hereby authorized to, and shall, join with the Company in the execution of any such supplemental indenture, to make any further appropriate

agreements and stipulations that may be therein contained, but the Trustee shall not be obligated to, but may in its discretion, enter

into any supplemental indenture that affects the Trustee’s own rights, duties or immunities under this Indenture or otherwise.

Any supplemental indenture authorized by the provisions

of this ‎Section 10.01 may be executed by the Company and the Trustee without the consent of the Holders of any of the Notes

at the time outstanding, notwithstanding any of the provisions of ‎Section 10.02.

Section 10.02. Supplemental Indentures

with Consent of Holders. With the consent (evidenced as provided in ‎Article 8) of the Holders of at least a majority of

the aggregate principal amount of the Notes then outstanding (determined in accordance with ‎Article 8 and including, without

limitation, consents obtained in connection with a repurchase of, or tender or exchange offer for, Notes), the Company, and the Trustee,

at the Company’s expense, may from time to time and at any time enter into an indenture or indentures supplemental hereto for the

purpose of adding any provisions to or changing in any manner or eliminating any of the provisions of this Indenture, the Notes or any

supplemental indenture or of modifying in any manner the rights of the Holders; provided, however, that, without the consent

of each Holder of an outstanding Note affected, no such supplemental indenture shall:

(a)            reduce

the principal amount of Notes whose Holders must consent to an amendment;

(b)            reduce

the rate of or extend the stated time for payment of any interest (including Special Interest and interest payable pursuant to ‎Section 2.03(c))

on any Note;

the principal amount of or extend the Maturity Date of any Note;

(d)            except

as required pursuant to this Indenture, make any change that adversely affects the conversion rights of any Notes;

(e)            reduce

the Redemption Price or the Fundamental Change Repurchase Price of any Note or amend or modify in any manner adverse to the Holders the

Company’s obligation to make such payments, whether through an amendment or waiver of provisions in the covenants, definitions

or otherwise;

(f)            make

any Note payable in a currency, or at a place of payment, other than that stated in the Note;

(g)            change

the ranking of the Notes in any manner adverse to Holders; or

(h)            make

any change in this ‎Article 10 that requires each Holder’s consent or in the waiver provisions in ‎Section 6.02

or ‎Section 6.09.

Upon the written request of the Company, and upon

the filing with the Trustee of evidence of the consent of the requisite Holders as aforesaid and subject to ‎Section 10.05,

the Trustee shall join with the Company in the execution of such supplemental indenture unless such supplemental indenture affects the

Trustee’s own rights, duties or immunities under this Indenture or otherwise, in which case the Trustee may in its discretion,

but shall not be obligated to, enter into such supplemental indenture.

Holders do not need under this ‎Section 10.02

to approve the particular form of any proposed supplemental indenture. It shall be sufficient if such Holders approve the substance thereof.

After any such supplemental indenture becomes effective, the Company shall deliver to the Holders (with a copy to the Trustee) a notice

briefly describing such supplemental indenture. However, the failure to give such notice to all the Holders (with a copy to the Trustee),

or any defect in the notice, will not impair or affect the validity of the supplemental indenture.

Section 10.03. Effect of Supplemental

Indentures. Upon the execution of any supplemental indenture pursuant to the provisions of this ‎Article 10, this Indenture

shall be and be deemed to be modified and amended in accordance therewith and the respective rights, limitation of rights, obligations,

duties and immunities under this Indenture of the Trustee, the Company and the Holders shall thereafter be determined, exercised and

enforced hereunder subject in all respects to such modifications and amendments and all the terms and conditions of any such supplemental

indenture shall be and be deemed to be part of the terms and conditions of this Indenture for any and all purposes.

Section 10.04. Notation on Notes.

Notes authenticated and delivered after the execution of any supplemental indenture pursuant to the provisions of this ‎Article 10

may, at the Company’s expense, bear a notation as to any matter provided for in such supplemental indenture. If the Company or

the Trustee shall so determine, new Notes so modified as to conform, in the opinion of the Board of Directors, to any modification of

this Indenture contained in any such supplemental indenture may, at the Company’s expense, be prepared and executed by the Company,

authenticated, upon receipt of a Company Order, by the Trustee (or an authenticating agent duly appointed by the Trustee pursuant to

‎Section 17.10) and delivered in exchange for the Notes then outstanding, upon surrender of such Notes then outstanding.

Section 10.05. Evidence of Compliance

of Supplemental Indenture to Be Furnished Trustee. In addition to the documents required by ‎Section 17.05, the Trustee

shall receive an Officers’ Certificate and an Opinion of Counsel as conclusive evidence that any supplemental indenture executed

pursuant hereto complies with the requirements of this ‎Article 10 and is permitted or authorized by this Indenture, that all

conditions precedent to such supplemental indenture have been satisfied and, with respect to such Opinion of Counsel, that such supplemental

indenture constitutes a legal, valid and binding obligation of the Company, enforceable against the Company in accordance with its terms,

subject to customary exceptions and qualifications.

Article 11

Consolidation, Merger, Sale, Conveyance and Lease

Section 11.01. Company May Consolidate,

Etc. on Certain Terms. Subject to the provisions of ‎Section 11.02, the Company shall not consolidate with or merge with

or into another Person or sell, convey, transfer or lease all or substantially all of the consolidated properties and assets of the Company

and the Company’s Subsidiaries, taken as a whole, to another Person, unless, in either case:

(a)            the

resulting, surviving or transferee Person (the “Successor Company”), if not the Company, shall be a corporation organized

and existing under the laws of the United States of America, any State thereof or the District of Columbia, and the Successor Company

(if not the Company) shall expressly assume, by supplemental indenture all of the obligations of the Company under the Notes and this

Indenture; and

(b)            immediately

after giving effect to such transaction, no Default or Event of Default shall have occurred and be continuing under this Indenture.

Section 11.02. Successor Corporation

to Be Substituted. In case of any such consolidation, merger, sale, conveyance, transfer or lease and upon the assumption by the

Successor Company, by supplemental indenture, executed and delivered to the Trustee, of the due and punctual payment of the principal

of and any accrued and unpaid Special Interest on all of the Notes, the due and punctual delivery or payment, as the case may be, of

any consideration due upon conversion of the Notes and the due and punctual performance of all of the covenants and conditions of this

Indenture to be performed by the Company, such Successor Company (if not the Company) shall succeed to and, except in the case of a lease

of all or substantially all of the consolidated properties and assets of the Company and the Company’s subsidiaries, taken as a

whole, shall be substituted for the Company, with the same effect as if it had been named herein as the party of the first part. Such

Successor Company thereupon may cause to be signed, and may issue either in its own name or in the name of the Company any or all of

the Notes issuable hereunder which theretofore shall not have been signed by the Company and delivered to the Trustee; and, upon the

order of such Successor Company instead of the Company and subject to all the terms, conditions and limitations in this Indenture prescribed,

the Trustee shall authenticate and shall deliver, or cause to be authenticated and delivered, any Notes that previously shall have been

signed and delivered by the Officers of the Company to the Trustee for authentication, and any Notes that such Successor Company thereafter

shall cause to be signed and delivered to the Trustee for that purpose. All the Notes so issued shall in all respects have the same legal

rank and benefit under this Indenture as the Notes theretofore or thereafter issued in accordance with the terms of this Indenture as

though all of such Notes had been issued at the date of the execution hereof. In the event of any such consolidation, merger, sale, conveyance

or transfer (but not in the case of a lease), upon compliance with this ‎Article 11 the Person named as the “Company”

in the first paragraph of this Indenture (or any successor that shall thereafter have become such in the manner prescribed in this ‎Article 11)

may be dissolved, wound up and liquidated at any time thereafter and, except in the case of a lease, such Person shall be released from

its liabilities as obligor and maker of the Notes and from its obligations under this Indenture and the Notes.

In case of any such consolidation, merger, sale,

conveyance, transfer or lease, such changes in phraseology and form (but not in substance) may be made in the Notes thereafter to be

issued as may be appropriate.

Section 11.03. Officers’ Certificate

and Opinion of Counsel to Be Given to Trustee. If a supplemental indenture is required pursuant to this ‎Article 11, no

such consolidation, merger, sale, conveyance, transfer or lease (other than any consolidation or merger where the Company is the surviving

entity) shall be effective unless the Trustee shall receive an Officers’ Certificate and an Opinion of Counsel as conclusive evidence

that any such consolidation, merger, sale, conveyance, transfer or lease and any such assumption and such supplemental indenture, complies

with the provisions of this ‎Article 11.

Article 12

Immunity of Incorporators, Stockholders, Officers and Directors

Section 12.01. Indenture and Notes Solely

Corporate Obligations. No recourse for the payment of the principal of or accrued and unpaid Special Interest, if any, on any Note,

nor for any claim based thereon or otherwise in respect thereof, and no recourse under or upon any obligation, covenant or agreement

of the Company in this Indenture or in any supplemental indenture or in any Note, nor because of the creation of any indebtedness represented

thereby, shall be had against any incorporator, stockholder, employee, agent, Officer or director or Subsidiary, as such, past, present

or future, of the Company or of any successor corporation, either directly or through the Company or any successor corporation, whether

by virtue of any constitution, statute or rule of law, or by the enforcement of any assessment or penalty or otherwise; it being

expressly understood that all such liability is hereby expressly waived and released as a condition of, and as a consideration for, the

execution of this Indenture and the issuance of the Notes.

Article 13

[Intentionally Omitted]

Article 14

Conversion of Notes

Section 14.01. Conversion Privilege.

(a) Subject to and upon compliance with the provisions of this ‎Article 14, each Holder of a Note shall have the right,

at such Holder’s option, to convert all or any portion (if the portion to be converted is $1,000 principal amount or an integral

multiple of $1,000 in excess thereof) of such Note (i) subject to satisfaction of the conditions described in ‎Section 14.01(b),

at any time prior to the close of business on the Business Day immediately preceding March 15, 2031, under the circumstances and

during the periods set forth in ‎Section 14.01(b), and (ii) regardless of the conditions described in ‎Section 14.01(b),

on or after March 15, 2031 and prior to the close of business on the second Scheduled Trading Day immediately preceding the Maturity

Date, in each case, at an initial conversion rate of 9.3042 shares of Common Stock (subject to adjustment as provided in this ‎Article 14,

the “Conversion Rate”) per $1,000 principal amount of Notes (subject to, and in accordance with, the settlement provisions

of ‎Section 14.02, the “Conversion Obligation”).

(b)            (i) Prior

to the close of business on the Business Day immediately preceding March 15, 2031, a Holder may surrender all or any portion of

its Notes for conversion at any time during the five Business Day period immediately after any five consecutive Trading Day period (the

“Measurement Period”) in which the Trading Price per $1,000 principal amount of Notes, as determined by the Company

following a request by a Holder of Notes in accordance with this subsection (b)(i), for each Trading Day of the Measurement Period was

less than 98% of the product of the Last Reported Sale Price of the Common Stock on each such Trading Day and the Conversion Rate on

each such Trading Day. The Trading Prices shall be determined by the Company in accordance with the bids solicited by the Bid Solicitation

Agent pursuant to this subsection (b)(i) and the definition of Trading Price set forth in this Indenture. The Company shall provide

written notice to the Bid Solicitation Agent (if other than the Company) of the three independent nationally recognized securities dealers

selected by the Company pursuant to the definition of Trading Price, along with appropriate contact information for each. The Bid Solicitation

Agent (if other than the Company) shall have no obligation to determine the Trading Price per $1,000 principal amount of Notes unless

the Company has requested in writing such determination and provided in writing the names and contact information of the three securities

dealers selected by the Company to provide bids to determine the Trading Price, and the Company shall have no obligation to make such

request (or, if the Company is acting as Bid Solicitation Agent, the Company shall have no obligation to determine the Trading Price

per $1,000 principal amount of Notes) unless a Holder or Holders of at least $5,000,000 aggregate principal amount of Notes provide the

Company with reasonable evidence that the Trading Price per $1,000 principal amount of Notes on any Trading Day would be less than 98%

of the product of the Last Reported Sale Price of the Common Stock on such Trading Day and the Conversion Rate on such Trading Day, at

which time the Company shall (x) instruct the three independent nationally recognized securities dealers to deliver bids to the

Bid Solicitation Agent and (y) irrevocably instruct the Bid Solicitation Agent in writing (if other than the Company) to determine,

or if the Company is acting as Bid Solicitation Agent, the Company shall determine, the Trading Price per $1,000 principal amount of

Notes based on the bids solicited by the Bid Solicitation Agent beginning on the next Trading Day and on each successive Trading Day

until the Trading Price per $1,000 principal amount of Notes is greater than or equal to 98% of the product of the Last Reported Sale

Price of the Common Stock and the Conversion Rate. If the Company is not acting as Bid Solicitation Agent, the Company shall identify

in writing to the Bid Solicitation Agent the three securities dealers selected by the Company to provide bids to determine the Trading

Price and the contact information for each. If (x) the Company is not acting as Bid Solicitation Agent, and the Company does not

instruct the Bid Solicitation Agent in writing to determine the Trading Price per $1,000 principal amount of Notes or identify in writing

to the Bid Solicitation Agent the three securities dealers selected by the Company to provide bids to determine the Trading Price and

the contact information for each when obligated as provided in the two immediately preceding sentences, or if the Company gives such

written instruction and information to the Bid Solicitation Agent and the Bid Solicitation Agent fails to make such determination or

(y) the Company is acting as Bid Solicitation Agent and the Company fails to obtain such bids or the Company fails to determine

the Trading Price when obligated as provided in the second immediately preceding sentence, then, in either case, the Trading Price per

$1,000 principal amount of Notes shall be deemed to be less than 98% of the product of the Last Reported Sale Price of the Common Stock

and the Conversion Rate on each Trading Day of such failure. If the Trading Price condition set forth above has been met, the Company

shall so notify in writing the Holders, the Trustee and the Conversion Agent (if other than the Trustee). Any such determination shall

be conclusive absent manifest error. If, at any time after the Trading Price condition set forth above has been met, the Trading Price

per $1,000 principal amount of Notes is greater than or equal to 98% of the product of the Last Reported Sale Price of the Common Stock

and the Conversion Rate for such date, the Company shall so notify in writing the Holders of the Notes, the Trustee and the Conversion

Agent (if other than the Trustee) and thereafter neither the Company nor the Bid Solicitation Agent (if other than the Company) shall

be required to solicit bids again until another request is made as provided in this ‎Section 14.01(b)(i).

(ii)            If,

prior to the close of business on the Business Day immediately preceding March 15, 2031, the Company elects to:

(A)            issue

to all or substantially all holders of the Common Stock any rights, options or warrants (other than in connection with a stockholder

rights plan, so long as such rights have not separated from the Common Stock) entitling them, for a period of not more than 45 calendar

days after the announcement date of such issuance, to subscribe for or purchase shares of the Common Stock at a price per share that

is less than the average of the Last Reported Sale Prices of the Common Stock for the 10 consecutive Trading Day period ending on, and

including, the Trading Day immediately preceding the date of announcement of such issuance; or

(B)            distribute

to all or substantially all holders of the Common Stock the Company’s assets, securities (other than solely the Common Stock) or

rights to purchase securities, which distribution has a per share value, as reasonably determined by the Company, exceeding 10% of the

Last Reported Sale Price of the Common Stock on the Trading Day preceding the date of announcement for such distribution,

then, in either case, subject to the proviso below, the Company shall

notify in writing all Holders of the Notes, the Trustee and the Conversion Agent (if other than the Trustee) at least 35 Scheduled Trading

Days prior to the Ex-Dividend Date for such issuance or distribution (or, if later, in the case of any such separation of rights issued

pursuant to a stockholder rights plan, as soon as reasonably practicable after the Company becomes aware that such separation or Trigger

Event has occurred or will occur); provided, however, that if the Company elects Physical Settlement (to the extent that

the Company has not elected another Settlement Method to apply, including pursuant to ‎Section 14.02) in the applicable notice

in respect of all conversions that occurs from, and including, the date the Company provides such notice to, and including, the close

of business on the Business Day immediately preceding the Ex-Dividend Date for such distribution or issuance (or, if earlier, the date

the Company announces that such issuance or distribution will not take place) (the “Distribution Trigger Irrevocable Physical

Settlement Period”), the Company shall be permitted to provide not less than 10 Scheduled Trading Days’ notice prior

to the Ex-Dividend Date for the applicable issuance or distribution, in which case the Company shall be required to settle all conversions

of Notes with a Conversion Date occurring during the Distribution Trigger Irrevocable Physical Settlement Period by Physical Settlement,

and the Company shall describe the same in such notice. Once the Company has given such notice, a Holder may surrender all or any portion

of its Notes for conversion at any time until the earlier of (1) the close of business on the Business Day immediately preceding

the Ex-Dividend Date for such issuance or distribution and (2) the Company’s announcement that such issuance or distribution

will not take place (or, if later, in the case of a separation or Trigger Event pursuant to a stockholder rights plan, until the 20th

Trading Day following the date on which the Company so notifies all Holders of the Notes), in each case, even if the Notes are not otherwise

convertible at such time; provided that Holders may not convert their Notes pursuant to this ‎Section 14.01(b)(ii) if

they participate (other than in the case of a share split or share combination), at the same time and upon the same terms as holders

of the Common Stock and solely as a result of holding the Notes, in any of the transactions described in clause (A) or (B) of

this ‎Section 14.01(b)(ii) without having to convert their Notes as if they held a number of shares of Common Stock equal

to the Conversion Rate multiplied by the principal amount (expressed in thousands) of Notes held by such Holder.

(iii)            If

a transaction or event that constitutes a Fundamental Change or a Make-Whole Fundamental Change occurs prior to the close of business

on the Business Day immediately preceding March 15, 2031, regardless of whether a Holder has the right to require the Company to

repurchase the Notes pursuant to ‎Section 15.02, or if the Company is a party to a Share Exchange Event (other than a Share

Exchange Event that is solely for the purpose of changing the Company’s jurisdiction of organization that (x) does not constitute

a Fundamental Change or a Make-Whole Fundamental Change and (y) results in a classification, conversion or exchange of outstanding

shares of Common Stock solely into shares of common stock of the surviving entity that are listed or quoted on any of The New York Stock

Exchange, The Nasdaq Global Select Market or The Nasdaq Global Market (or any of their respective successors) and such common stock becomes

Reference Property for the Notes) that occurs prior to the close of business on the Business Day immediately preceding March 15,

2031 (each such Fundamental Change, Make-Whole Fundamental Change or Share Exchange Event, a “Corporate Event”), all

or any portion of a Holder’s Notes may be surrendered for conversion at any time after the effective date of such Corporate Event

until the earlier of (x) the close of business on the Business Day immediately preceding March 15, 2031 and (y) the

earlier of (I) 35 Trading Days after the actual effective date of such Corporate Event or, if such Corporate Event also constitutes

a Fundamental Change, the close of business on the Business Day immediately preceding the related Fundamental Change Repurchase Date

and (II) the close of business on the second Scheduled Trading Day immediately preceding the Maturity Date. The Company shall notify

Holders, the Trustee and the Conversion Agent (if other than the Trustee) in writing no later than the actual effective date of any such

Corporate Event.

(iv)            Prior

to the close of business on the Business Day immediately preceding March 15, 2031, a Holder may surrender all or any portion of

its Notes for conversion at any time during any calendar quarter commencing after the calendar quarter ending on September 30,

2026 (and only during such calendar quarter), if the Last Reported Sale Price of the Common Stock for at least 20 Trading Days (whether

or not consecutive) during the period of 30 consecutive Trading Days ending on, and including, the last Trading Day of the immediately

preceding calendar quarter is greater than or equal to 130% of the Conversion Price on each applicable Trading Day.

(v)            If

the Company calls any or all of the Notes for redemption pursuant to ‎Article 16 prior to the close of business on the Business

Day immediately preceding March 15, 2031, then a Holder may surrender all or any portion of its Notes for conversion at any time

prior to the close of business on the second Scheduled Trading Day immediately preceding the Redemption Date, even if the Notes are not

otherwise convertible at such time. After that time, the right to convert pursuant to this ‎Section 14.01(b)(v) shall

expire, unless the Company defaults in the payment of the Redemption Price, in which case a Holder of Notes may convert its Notes until

the Redemption Price has been paid or duly provided for.

Section 14.02. Conversion Procedure;

Settlement Upon Conversion.

(a)            Subject

to this ‎Section 14.02, ‎Section 14.03(b) and ‎Section 14.07(a), upon conversion of any Note, the

Company shall pay or deliver, as the case may be, to the converting Holder, in respect of each $1,000 principal amount of Notes being

converted, cash (“Cash Settlement”), shares of Common Stock, together with cash, if applicable, in lieu of delivering

any fractional share of Common Stock in accordance with subsection ‎(j) of this ‎Section 14.02 (“Physical

Settlement”) or a combination of cash and shares of Common Stock, together with cash, if applicable, in lieu of delivering

any fractional share of Common Stock in accordance with subsection ‎(j) of this ‎Section 14.02 (“Combination

Settlement”), at its election, as set forth in this ‎Section 14.02.

(i)            All

conversions for which the relevant Conversion Date occurs after the Company’s issuance of a Redemption Notice with respect to the

Notes and prior to the related Redemption Date, and all conversions for which the relevant Conversion Date occurs on or after March 15,

2031 shall be settled using the same Settlement Method.

(ii)            Except

for any conversions for which the relevant Conversion Date occurs after the Company’s issuance of a Redemption Notice with respect

to the Notes but prior to the related Redemption Date, and any conversions for which the relevant Conversion Date occurs on or after

March 15, 2031, the Company shall use the same Settlement Method for all conversions occurring on the same Conversion Date, but

the Company shall not have any obligation to use the same Settlement Method with respect to conversions occurring on different Conversion

Dates.

(iii)            If,

in respect of any Conversion Date (or one of the periods described in the fourth immediately succeeding set of parentheses, as the case

may be), the Company elects a Settlement Method, the Company shall deliver a notice (the “Settlement Notice”) of the

relevant Settlement Method in respect of such Conversion Date (or such period, as the case may be) in writing to converting Holders,

the Trustee and the Conversion Agent (if other than the Trustee) no later than the close of business on the Trading Day immediately following

the relevant Conversion Date (or, in the case of any conversions for which the relevant Conversion Date occurs (x) after the date

of issuance of a Redemption Notice with respect to the Notes and prior to the close of business on the second Scheduled Trading Day immediately

preceding the related Redemption Date, in such Redemption Notice, or (y) on or after March 15, 2031, no later than March 15,

2031). Delivery of such Settlement Notice is irrevocable. If the Company does not elect a Settlement Method prior to the deadline set

forth in the immediately preceding sentence, the Company shall no longer have the right to elect Cash Settlement or Physical Settlement

for such conversion and the Company shall be deemed to have elected Combination Settlement in respect of its Conversion Obligation, and

the Specified Dollar Amount per $1,000 principal amount of Notes shall be equal to $1,000. Such Settlement Notice shall specify the relevant

Settlement Method and in the case of an election of Combination Settlement, the relevant Settlement Notice shall indicate the Specified

Dollar Amount per $1,000 principal amount of Notes. If the Company delivers a Settlement Notice electing Combination Settlement in respect

of its Conversion Obligation but does not indicate a Specified Dollar Amount per $1,000 principal amount of Notes in such Settlement

Notice, the Specified Dollar Amount per $1,000 principal amount of Notes shall be deemed to be $1,000. If the Company calls any Notes

for redemption pursuant to ‎Article 16, and the related Redemption Date is on or after March 15, 2031 (x) if the

date of the relevant Redemption Notice occurs prior to the date the Company elects (or is deemed to have elected) a Settlement Method

in respect of all conversions with a Conversion Date occurring on or after March 15, 2031, then, in respect of all conversions

with a Conversion Date occurring on or after March 15, 2031, the Company must elect the Settlement Method that the Company elected

(or was deemed to have elected) in such Redemption Notice and (y) if the date of such Redemption Notice occurs on or after the

date the Company elects (or is deemed to have elected) a Settlement Method in respect of all conversions with a Conversion Date occurring

on or after March 15, 2031, then, the Company must elect in such Redemption Notice the Settlement Method that the Company elected

(or was deemed to have elected) in respect of all conversions with a Conversion Date occurring on or after March 15, 2031.

(iv)            The

cash, shares of Common Stock or combination of cash and shares of Common Stock in respect of any conversion of Notes (the “Settlement

Amount”) shall be computed as follows:

(A)            if

the Company elects to satisfy its Conversion Obligation in respect of such conversion by Physical Settlement, the Company shall deliver

to the converting Holder in respect of each $1,000 principal amount of Notes being converted a number of shares of Common Stock equal

to the Conversion Rate in effect on the Conversion Date (plus cash in lieu of any fractional share);

(B)            if

the Company elects to satisfy its Conversion Obligation in respect of such conversion by Cash Settlement, the Company shall pay to the

converting Holder in respect of each $1,000 principal amount of Notes being converted cash in an amount equal to the sum of the Daily

Conversion Values for each of the 25 consecutive Trading Days during the related Observation Period; and

the Company elects (or is deemed to have elected) to satisfy its Conversion Obligation in respect of such conversion by Combination Settlement,

the Company shall pay or deliver, as the case may be, in respect of each $1,000 principal amount of Notes being converted, a Settlement

Amount equal to the sum of the Daily Settlement Amounts for each of the 25 consecutive Trading Days during the related Observation Period

(plus cash in lieu of any fractional share).

(v)            The

Daily Settlement Amounts (if applicable) and the Daily Conversion Values (if applicable) shall be determined by the Company promptly

following the last day of the Observation Period. Promptly after such determination of the Daily Settlement Amounts or the Daily Conversion

Values, as the case may be, and the amount of cash payable in lieu of delivering any fractional share of Common Stock, and in any event

within one (1) Business Day following the last day of the Observation Period, the Company shall notify the Trustee and the Conversion

Agent (if other than the Trustee) in writing of its determination of the Daily Settlement Amounts or the Daily Conversion Values, as

the case may be, and the amount of cash payable in lieu of delivering fractional shares of Common Stock and the calculation thereof in

reasonable detail or in such detail as requested by the Depositary. The Trustee and the Conversion Agent (if other than the Trustee)

shall have no responsibility for any such determination.

(vi)            At

any time prior to March 15, 2031, the Company may irrevocably elect to satisfy its Conversion Obligation with respect to the Notes

to be converted after the date of such election by delivering cash up to the aggregate principal amount of Notes to be converted, and

shares of the Common Stock, cash or a combination thereof in respect of the remainder, if any, of its Conversion Obligation. Upon making

such election, the Company shall promptly (x) provide written notice to the Holders, the Trustee and the Conversion Agent (if other

than the Trustee) and (y) issue a current report on Form 8-K or press release or publish on its website to announce that

the Company has made such an election.

(b)            Subject

to ‎Section 14.02(e), before any Holder of a Note shall be entitled to convert a Note as set forth above, such Holder shall

(i) in the case of a Global Note, comply with the procedures of the Depositary in effect at that time (any instruction to convert

transmitted to the Depositary shall be irrevocable) and, if required, pay funds equal to any Special Interest payable on the next Special

Interest Payment Date to which such Holder is not entitled as set forth in ‎Section 14.02(h) and/or all transfer or similar

taxes, if any, that are such Holder’s responsibility as set forth in ‎Section 14.02(e) and (ii) in the case

of a Physical Note or Global Notes not approved for processing through the Depositary: (1) complete, manually sign and deliver

an irrevocable notice to the Conversion Agent as set forth in the Form of Notice of Conversion (or a facsimile, PDF or other electronic

transmission thereof) (a “Notice of Conversion”) at the office of the Conversion Agent and state in writing therein

the principal amount of Notes to be converted and the name or names (with addresses) in which such Holder wishes the certificate or certificates

for any shares of Common Stock to be delivered upon settlement of the Conversion Obligation to be registered, (2) surrender such

Notes, duly endorsed to the Company or in blank (and accompanied by appropriate endorsement and transfer documents), at the office of

the Conversion Agent, (3) if required, furnish appropriate endorsements and transfer documents, (4) if required, pay funds

equal to any Special Interest payable on the next Special Interest Payment Date to which such Holder is not entitled as set forth in

‎Section 14.02(h) and (5) if required by ‎Section 14.02(e), pay any transfer or similar taxes that are

such Holder’s responsibility. The Trustee (and if different, the Conversion Agent) shall notify the Company of any conversion pursuant

to this ‎Article 14 no more than one (1) Business Day after the Conversion Date for such conversion. No Notice of Conversion

with respect to any Notes may be surrendered by a Holder thereof if such Holder has also delivered a Fundamental Change Repurchase Notice

to the Company in respect of such Notes and has not validly withdrawn such Fundamental Change Repurchase Notice in accordance with ‎Section 15.03.

If more than one Note shall be surrendered for

conversion at one time by the same Holder, the Conversion Obligation with respect to such Notes shall be computed on the basis of the

aggregate principal amount of the Notes (or specified portions thereof to the extent permitted thereby) so surrendered.

Note shall be deemed to have been converted immediately prior to the close of business on the date (the “Conversion Date”)

that the Holder has complied with the requirements set forth in subsection ‎(b) above. Except as set forth in ‎‎Section 14.03(b) and

‎Section 14.07(a), the Company shall pay or deliver, as the case may be, the consideration due in respect of the Conversion

Obligation on the second Business Day immediately following the relevant Conversion Date, if the Company elects Physical Settlement (provided

that, with respect to any Conversion Date occurring on or after the Special Interest Record Date immediately preceding the Maturity Date,

the Company shall pay or deliver, as the case may be, such consideration due upon Physical Settlement in respect of the Conversion Obligation

on the Maturity Date), or on the second Business Day immediately following the last Trading Day of the Observation Period, in the case

of any other Settlement Method. If any shares of Common Stock are due to a converting Holder, the Company shall issue or cause to be

issued, and deliver (if applicable) to the converting Holder, or such Holder’s nominee or nominees, the full number of shares of

Common Stock to which such Holder shall be entitled, in book-entry format through the Depositary, in satisfaction of the Company’s

Conversion Obligation.

(d)            In

case any Physical Note shall be surrendered for partial conversion, the Company shall execute and the Trustee shall authenticate and

deliver to or upon the written order of the Holder of the Physical Note so surrendered a new Physical Note or Physical Notes in authorized

denominations in an aggregate principal amount equal to the unconverted portion of the surrendered Physical Note, without payment of

any service charge by the converting Holder but, if required by the Company or Trustee, with payment of a sum sufficient to cover any

documentary, stamp or similar issue or transfer tax or similar governmental charge required by law or that may be imposed in connection

therewith as a result of the name of the Holder of the new Physical Notes issued upon such conversion being different from the name of

the Holder of the old Physical Notes surrendered for such conversion.

(e)            If

a Holder submits a Note for conversion, the Company shall pay any documentary, stamp or similar issue or transfer tax due on the issue

of any shares of Common Stock upon conversion, unless the tax is due because the Holder requests such shares to be issued in a name other

than the Holder’s name, in which case the Holder shall pay that tax. The Company may refuse to deliver the certificates representing

the shares of Common Stock being issued in a name other than the Holder’s name until the Company receives a sum sufficient to pay

any tax that is due by such Holder in accordance with the immediately preceding sentence.

(f)            Except

as provided in ‎Section 14.04, no adjustment shall be made for dividends on any shares of Common Stock issued upon the conversion

of any Note as provided in this Article 14.

(g)            Upon

the conversion of an interest in a Global Note, the Trustee, or the Custodian at the direction of the Trustee, shall make a notation

on such Global Note as to the reduction in the principal amount represented thereby. The Company shall notify the Trustee in writing

of any conversion of Notes effected through any Conversion Agent other than the Trustee.

(h)            Upon

conversion, a Holder shall not receive any separate cash payment for accrued and unpaid Special Interest, if any, except as set forth

below and the Company shall not be required to adjust the Conversion Rate for any accrued and unpaid Special Interest. The Company’s

settlement of the full Conversion Obligation shall be deemed to satisfy in full its obligation to pay the principal amount of the Note

and accrued and unpaid Special Interest, if any, to, but not including, the relevant Conversion Date. As a result, accrued and unpaid

Special Interest, if any, to, but not including, the relevant Conversion Date shall be deemed to be paid in full rather than cancelled,

extinguished or forfeited. Upon a conversion of Notes into a combination of cash and shares of Common Stock, any accrued and unpaid Special

Interest will be deemed to be paid first out of the cash paid upon such conversion. Notwithstanding the foregoing, if Notes are converted

after the close of business on a Special Interest Record Date and prior to the open of business on the corresponding Special Interest

Payment Date, Holders of such Notes as of the close of business on such Special Interest Record Date will receive the full amount of

Special Interest, if any, payable on such Notes on the corresponding Special Interest Payment Date notwithstanding the conversion. However,

Notes surrendered for conversion during the period from the close of business on any Special Interest Record Date to the open of business

on the immediately following Special Interest Payment Date must be accompanied by funds equal to the amount of any Special Interest payable

on the Notes so converted on the corresponding Special Interest Payment Date; provided that no such payment shall be required

(1) for conversions of Notes following the close of business on the Special Interest Record Date immediately preceding the Maturity

Date, if Special Interest is payable on the Maturity Date; (2) if the Company has specified a Redemption Date that is after a Special

Interest Record Date and on or prior to the second Scheduled Trading Day immediately following the corresponding Special Interest Payment

Date; (3) if the Company has specified a Fundamental Change Repurchase Date that is after a Special Interest Record Date and on

or prior to the Business Day immediately following the corresponding Special Interest Payment Date; or (4) to the extent of any

Defaulted Amounts or Special Interest, if any Defaulted Amounts or Special Interest exists at the time of conversion with respect to

such Note. For the avoidance of doubt, all Holders of record as of the close of business on the Special Interest Record Date immediately

preceding the Maturity Date (if and to the extent Special Interest is payable on the Maturity Date) shall receive the full payment of

Special Interest due on the Maturity Date in cash regardless of whether their Notes have been converted following such Special Interest

Record Date.

(i)            The

Person in whose name the shares of Common Stock shall be issuable upon conversion shall be treated as a stockholder of record as of the

close of business on the relevant Conversion Date (if the Company elects to satisfy the related Conversion Obligation by Physical Settlement)

or the last Trading Day of the relevant Observation Period (if the Company elects to satisfy the related Conversion Obligation by Combination

Settlement), as the case may be. Upon a conversion of Notes, such Person shall no longer be a Holder of such Notes surrendered for conversion.

(j)            The

Company shall not issue any fractional share of Common Stock upon conversion of the Notes and shall instead pay cash in lieu of delivering

any fractional share of Common Stock issuable upon conversion based on the Daily VWAP for the relevant Conversion Date or, if such Conversion

Date is not a Trading Day, the immediately preceding Trading Day (in the case of Physical Settlement) or based on the Daily VWAP for

the last Trading Day of the relevant Observation Period (in the case of Combination Settlement). For each Note surrendered for conversion,

if the Company has elected (or is deemed to have elected) Combination Settlement, the full number of shares that shall be issued upon

conversion thereof shall be computed on the basis of the aggregate Daily Settlement Amounts for the relevant Observation Period and any

fractional shares of Common Stock remaining after such computation shall be paid in cash.

Section 14.03. Increased Conversion Rate

Applicable to Certain Notes Surrendered in Connection with Make-Whole Fundamental Changes or a Redemption Notice. (a)  If (x) the

Effective Date of a Make-Whole Fundamental Change occurs prior to the Maturity Date or (y) the Company gives a Redemption Notice

with respect to any or all of the Notes in accordance with ‎Section 16.02 and, in each case, a Holder elects to convert its

Notes in connection with such Make-Whole Fundamental Change or such Redemption Notice, as applicable, the Company shall, under the circumstances

described below, increase the Conversion Rate for the Notes so surrendered for conversion by a number of additional shares of Common

Stock (the “Additional Shares”), as described below. A conversion of Notes shall be deemed for these purposes to be

“in connection with” such Make-Whole Fundamental Change if the relevant Notice of Conversion is received by the Conversion

Agent from, and including, the Effective Date of the Make-Whole Fundamental Change up to, and including, the Business Day immediately

prior to the related Fundamental Change Repurchase Date (or, in the case of a Make-Whole Fundamental Change that would have been a Fundamental

Change but for the proviso in clause (b) of the definition thereof, the 35th Trading Day immediately following the Effective

Date of such Make-Whole Fundamental Change) (such period, the “Make-Whole Fundamental Change Period”). A conversion

of Notes shall be deemed for these purposes to be “in connection with” a Redemption Notice if the relevant Notice of Conversion

is received by the Conversion Agent from, and including, the date of the Redemption Notice until the close of business on the second

Scheduled Trading Day immediately preceding the Redemption Date.

(b)            Upon

surrender of Notes for conversion in connection with a Make-Whole Fundamental Change pursuant to ‎Section 14.01(b)(iii) or

a Redemption Notice pursuant to ‎Section 14.01(b)(v), the Company shall, at its option, satisfy the related Conversion Obligation

by Physical Settlement, Cash Settlement or Combination Settlement in accordance with ‎Section 14.02; provided, however,

that if, at the effective time of a Make-Whole Fundamental Change described in clause (b) of the definition of Fundamental Change,

the Reference Property following such Make-Whole Fundamental Change is composed entirely of cash, for any conversion of Notes following

the Effective Date of such Make-Whole Fundamental Change, the Conversion Obligation shall be calculated based solely on the Stock Price

for the transaction and shall be deemed to be an amount of cash per $1,000 principal amount of converted Notes equal to the Conversion

Rate (including any adjustment for Additional Shares), multiplied by such Stock Price. In such event, the Conversion Obligation

shall be paid to Holders in cash on the second Business Day following the Conversion Date. The Company shall notify the Holders of Notes,

the Trustee and the Conversion Agent (if other than the Trustee) in writing of the Effective Date of any Make-Whole Fundamental Change

no later than five Business Days after such Effective Date.

number of Additional Shares, if any, by which the Conversion Rate shall be increased shall be determined by reference to the table below,

based on the date on which the Make-Whole Fundamental Change occurs or becomes effective or the date of the Redemption Notice, as the

case may be, (in each case, the “Effective Date”) and the price (the “Stock Price”) paid (or deemed

to be paid) per share of the Common Stock in the Make-Whole Fundamental Change or with respect to the Optional Redemption, as the case

may be. If the holders of the Common Stock receive in exchange for their Common Stock only cash in a Make-Whole Fundamental Change described

in clause (b) of the definition of Fundamental Change, the Stock Price shall be the cash amount paid per share. Otherwise, the

Stock Price shall be the average of the Last Reported Sale Prices of the Common Stock over the five consecutive Trading Day period ending

on, and including, the Trading Day immediately preceding the Effective Date of the Make-Whole Fundamental Change or the date of the Redemption

Notice, as the case may be. The Company shall make appropriate adjustments to the Stock Price, in its good faith determination, to account

for any adjustment to the Conversion Rate that becomes effective, or any event requiring an adjustment to the Conversion Rate where the

Ex-Dividend Date, Effective Date (as such term is used in ‎Section 14.04) or expiration date of the event occurs during such

five consecutive Trading Day period. If a conversion in connection with a Redemption Notice would also be deemed to be in connection

with a Make-Whole Fundamental Change, a Holder of the Notes to be converted shall be entitled to a single increase to the Conversion

Rate with respect to the first to occur of the date of the applicable Redemption Notice or the Effective Date of the applicable Make-Whole

Fundamental Change, and the later event shall be deemed not to have occurred for purposes of this ‎Section 14.03.

(d)            The

Stock Prices set forth in the column headings of the table below shall be adjusted as of any date on which the Conversion Rate of the

Notes is otherwise adjusted. The adjusted Stock Prices shall equal the Stock Prices applicable immediately prior to such adjustment,

multiplied by a fraction, the numerator of which is the Conversion Rate immediately prior to such adjustment giving rise to the

Stock Price adjustment and the denominator of which is the Conversion Rate as so adjusted. The number of Additional Shares set forth

in the table below shall be adjusted in the same manner and at the same time as the Conversion Rate as set forth in ‎Section 14.04.

(e)            The

following table sets forth the number of Additional Shares of Common Stock by which the Conversion Rate shall be increased per $1,000

principal amount of Notes pursuant to this ‎Section 14.03 for each Stock Price and Effective Date set forth below:

Stock

Price

Effective Date

$76.77

$95.00

$107.48

$125.00

$139.72

$150.00

$200.00

$400.00

$600.00

$800.00

June 18, 2026

3.7217

2.5792

2.0597

1.5430

1.2340

1.0647

0.5586

0.0689

0.0050

0.0000

June 15, 2027

3.7217

2.5792

2.0452

1.4975

1.1755

1.0013

0.4947

0.0471

0.0002

0.0000

June 15, 2028

3.7217

2.5705

1.9710

1.3954

1.0650

0.8897

0.4005

0.0241

0.0000

June 15, 2029

3.7217

2.4283

1.7882

1.1946

0.8678

0.7004

0.2667

0.0056

0.0000

June 15, 2030

3.7217

2.0961

1.4094

0.8215

0.5307

0.3945

0.1007

0.0000

June 15, 2031

3.7217

1.2221

0.0000

The exact Stock Price and Effective Date may not

be set forth in the table above, in which case:

(i)            if

the Stock Price is between two Stock Prices in the table above or the Effective Date is between two Effective Dates in the table, the

number of Additional Shares shall be determined by a straight-line interpolation between the number of Additional Shares set forth for

the higher and lower Stock Prices and the earlier and later Effective Dates, as applicable, based on a 365-day year;

(ii)            if

the Stock Price is greater than $800.00 per share (subject to adjustment in the same manner as the Stock Prices set forth in the

column headings of the table above pursuant to subsection (d) above), no Additional Shares shall be added to the Conversion Rate

for the Notes; and

(iii)            if

the Stock Price is less than $76.77 per share (subject to adjustment in the same manner as the Stock Prices set forth in the column

headings of the table above pursuant to subsection (d) above), no Additional Shares shall be added to the Conversion Rate for the

Notes.

Notwithstanding the foregoing, in no event shall the Conversion Rate

per $1,000 principal amount of Notes exceed 13.0259 shares of Common Stock, subject to adjustment in the same manner as the Conversion

Rate pursuant to ‎Section 14.04.

(f)            Nothing

in this ‎Section 14.03 shall prevent an adjustment to the Conversion Rate pursuant to ‎Section 14.04 in respect of

a Make-Whole Fundamental Change.

Section 14.04. Adjustment of Conversion

Rate. The Conversion Rate shall be adjusted from time to time by the Company if any of the following events occurs, except that the

Company shall not make any adjustments to the Conversion Rate if each Holder of the Notes participates (other than in the case of (x) a

share split or share combination or (y) a tender or exchange offer), at the same time and upon the same terms as holders of the

Common Stock and solely as a result of holding the Notes, in any of the transactions described in this ‎Section 14.04, without

having to convert its Notes, as if it held a number of shares of Common Stock equal to the Conversion Rate, multiplied by the

principal amount (expressed in thousands) of Notes held by such Holder.

(a)            If

the Company exclusively issues shares of Common Stock as a dividend or distribution on shares of the Common Stock, or if the Company

effects a share split or share combination, the Conversion Rate shall be adjusted based on the following formula:

where,

CR0 =

the

Conversion Rate in effect immediately prior to the open of business on the Ex-Dividend Date

of such dividend or distribution, or immediately prior to the open of business on the Effective

Date of such share split or share combination, as applicable;

CR' =

the Conversion Rate in effect immediately after the

open of business on such Ex-Dividend Date or Effective Date, as applicable;

OS0 =

the

number of shares of Common Stock outstanding immediately prior to the open of business on

such Ex-Dividend Date or Effective Date (before giving effect to any such dividend, distribution,

share split or share combination), as applicable; and

OS' =

the number of shares of Common Stock outstanding immediately

after giving effect to such dividend, distribution, share split or share combination, as

applicable.

Any adjustment made under this ‎Section 14.04(a) shall

become effective immediately after the open of business on the Ex-Dividend Date for such dividend or distribution, or immediately after

the open of business on the Effective Date for such share split or share combination, as applicable. If any dividend or distribution

of the type described in this ‎Section 14.04(a) is declared but not so paid or made, the Conversion Rate shall be immediately

readjusted, effective as of the date the Company determines not to pay such dividend or distribution, to the Conversion Rate that would

then be in effect if such dividend or distribution had not been declared.

(b)            If

the Company issues to all or substantially all holders of the Common Stock any rights, options or warrants (other than in connection

with a stockholder rights plan) entitling them, for a period of not more than 45 calendar days after the announcement date of such issuance,

to subscribe for or purchase shares of the Common Stock at a price per share that is less than the average of the Last Reported Sale

Prices of the Common Stock for the 10 consecutive Trading Day period ending on, and including, the Trading Day immediately preceding

the date of announcement of such issuance, the Conversion Rate shall be increased based on the following formula:

where,

CR0 =

the

Conversion Rate in effect immediately prior to the open of business on the Ex-Dividend Date

for such issuance;

CR' =

the Conversion Rate in effect immediately after the

open of business on such Ex-Dividend Date;

OS0 =

the

number of shares of Common Stock outstanding immediately prior to the open of business on

such Ex-Dividend Date;

X =

the total number of shares of Common Stock issuable

pursuant to such rights, options or warrants; and

Y =

the number of shares of Common Stock equal to the aggregate

price payable to exercise such rights, options or warrants, divided by the average

of the Last Reported Sale Prices of the Common Stock over the 10 consecutive Trading Day

period ending on, and including, the Trading Day immediately preceding the date of announcement

of the issuance of such rights, options or warrants.

Any increase made under this ‎Section 14.04(b) shall

be made successively whenever any such rights, options or warrants are issued and shall become effective immediately after the open of

business on the Ex-Dividend Date for such issuance. To the extent that shares of the Common Stock are not delivered after the expiration

of such rights, options or warrants, the Conversion Rate shall be decreased to the Conversion Rate that would then be in effect had the

increase with respect to the issuance of such rights, options or warrants been made on the basis of delivery of only the number of shares

of Common Stock actually delivered. If such rights, options or warrants are not so issued, the Conversion Rate shall be decreased to

the Conversion Rate that would then be in effect if such Ex-Dividend Date for such issuance had not occurred.

For purposes of this ‎Section 14.04(b) and

for the purpose of ‎Section 14.01(b)(ii)(A), in determining whether any rights, options or warrants entitle the holders of

the Common Stock to subscribe for or purchase shares of the Common Stock at less than such average of the Last Reported Sale Prices of

the Common Stock for the 10 consecutive Trading Day period ending on, and including, the Trading Day immediately preceding the date of

announcement for such issuance, and in determining the aggregate offering price of such shares of Common Stock, there shall be taken

into account any consideration received by the Company for such rights, options or warrants and any amount payable on exercise or conversion

thereof, the value of such consideration, if other than cash, to be determined by the Company in good faith.

the Company distributes shares of its Capital Stock, evidences of its indebtedness, other assets or property of the Company or rights,

options or warrants to acquire its Capital Stock or other securities, to all or substantially all holders of the Common Stock, excluding

(i) dividends, distributions or issuances (including share splits) as to which an adjustment was effected (or would have been effected

but for ‎Section 14.04(j)) pursuant to ‎Section 14.04(a) or ‎Section 14.04(b), (ii) dividends

or distributions paid exclusively in cash as to which the provisions set forth in ‎Section 14.04(d) shall apply, (iii) distributions

of Reference Property upon conversion of, or exchange for, the Common Stock in a Share Exchange Event, including, for the avoidance of

doubt, any ability of holders of Common Stock to make an election with respect to the consideration they will receive in any such Share

Exchange Event, (iv) except as otherwise provided in this ‎Section 14.04(c) and ‎Section 14.11, rights

issued pursuant to a stockholder rights plan of the Company, and (v) Spin-Offs as to which the provisions set forth below in this

‎Section 14.04(c) shall apply (any of such shares of Capital Stock, evidences of indebtedness, other assets or property

or rights, options or warrants to acquire Capital Stock or other securities, the “Distributed Property”), then the

Conversion Rate shall be increased based on the following formula:

where,

CR0 =

the

Conversion Rate in effect immediately prior to the open of business on the Ex-Dividend Date

for such distribution;

CR' =

the Conversion Rate in effect immediately after the

open of business on such Ex-Dividend Date;

SP0 =

the

average of the Last Reported Sale Prices of the Common Stock over the 10 consecutive Trading

Day period ending on, and including, the Trading Day immediately preceding the Ex-Dividend

Date for such distribution; and

FMV =

the fair market value (as determined by the Company

in good faith) of the Distributed Property with respect to each outstanding share of the

Common Stock on the Ex-Dividend Date for such distribution.

Any increase made under the portion of this ‎Section 14.04(c) above

shall become effective immediately after the open of business on the Ex-Dividend Date for such distribution. If such distribution is

not so paid or made, the Conversion Rate shall be decreased to the Conversion Rate that would then be in effect if such distribution

had not been declared. Notwithstanding the foregoing, if “FMV” (as defined above) is equal to or greater than “SP0”

(as defined above), in lieu of the foregoing increase, each Holder of a Note shall receive, in respect of each $1,000 principal amount

thereof, at the same time and upon the same terms as holders of the Common Stock receive the Distributed Property and without having

to convert its Notes, the amount and kind of Distributed Property such Holder would have received if such Holder owned a number of shares

of Common Stock equal to the Conversion Rate in effect on the Ex-Dividend Date for the distribution. If the Company determines the “FMV”

(as defined above) of any distribution for purposes of this ‎Section 14.04(c) by reference to the actual or when-issued

trading market for any securities, it shall in doing so consider the prices in such market over the same period used in computing the

Last Reported Sale Prices of the Common Stock over the 10 consecutive Trading Day period ending on, and including, the Trading Day immediately

preceding the Ex-Dividend Date for such distribution.

With respect to an adjustment pursuant to this

‎Section 14.04(c) where there has been a payment of a dividend or other distribution on the Common Stock of shares of

Capital Stock of any class or series, or similar equity interest, of or relating to a Subsidiary or other business unit of the Company,

that are, or, when issued, will be, listed or admitted for trading on a U.S. national securities exchange (a “Spin-Off”),

the Conversion Rate shall be increased based on the following formula:

where,

CR0 =

the Conversion Rate in effect

immediately prior to the end of the Valuation Period;

CR' =

the Conversion Rate in effect immediately after the end of the Valuation Period;

FMV0 =

the average of the Last Reported

Sale Prices of the Capital Stock or similar equity interest distributed to holders of the

Common Stock applicable to one share of the Common Stock (determined by reference to the

definition of Last Reported Sale Price as set forth in ‎Section 1.01 as if references

therein to Common Stock were to such Capital Stock or similar equity interest) over the first

10 consecutive Trading Day period after, and including, the Ex-Dividend Date of the Spin-Off

(the “Valuation Period”); and

MP0 =

the

average of the Last Reported Sale Prices of the Common Stock over the Valuation Period.

The increase to the Conversion Rate under the

preceding paragraph shall occur at the close of business on the last Trading Day of the Valuation Period; provided that (x) in

respect of any conversion of Notes for which Physical Settlement is applicable, if the relevant Conversion Date occurs during the Valuation

Period, references to “10” in the preceding paragraph shall be deemed to be replaced with such lesser number of Trading Days

as have elapsed from, and including, the Ex-Dividend Date of such Spin-Off to, and including, the Conversion Date in determining the

Conversion Rate and (y) in respect of any conversion of Notes for which Cash Settlement or Combination Settlement is applicable,

for any Trading Day that falls within the relevant Observation Period for such conversion and within the Valuation Period, references

to “10” in the preceding paragraph shall be deemed to be replaced with such lesser number of Trading Days as have elapsed

from, and including, the Ex-Dividend Date of such Spin-Off to, and including, such Trading Day in determining the Conversion Rate as

of such Trading Day. If any dividend or distribution constituting a Spin-Off is declared but not so paid or made, the Conversion Rate

shall be immediately decreased, effective as of the date the Company determines not to pay or make such dividend or distribution, to

the Conversion Rate that would then be in effect if such dividend or distribution had not been declared or announced.

For purposes of this ‎Section 14.04(c) (and

subject in all respect to ‎Section 14.11), rights, options or warrants distributed by the Company to all holders of the Common

Stock entitling them to subscribe for or purchase shares of the Company’s Capital Stock, including Common Stock (either initially

or under certain circumstances), which rights, options or warrants, until the occurrence of a specified event or events (“Trigger

Event”): (i) are deemed to be transferred with such shares of the Common Stock; (ii) are not exercisable; and (iii) are

also issued in respect of future issuances of the Common Stock, shall be deemed not to have been distributed for purposes of this ‎Section 14.04(c) (and

no adjustment to the Conversion Rate under this ‎Section 14.04(c) will be required) until the occurrence of the earliest

Trigger Event, whereupon such rights, options or warrants shall be deemed to have been distributed and an appropriate adjustment (if

any is required) to the Conversion Rate shall be made under this ‎Section 14.04(c). If any such right, option or warrant, including

any such existing rights, options or warrants distributed prior to the date of this Indenture, are subject to events, upon the occurrence

of which such rights, options or warrants become exercisable to purchase different securities, evidences of indebtedness or other assets,

then the date of the occurrence of any and each such event shall be deemed to be the date of distribution and Ex-Dividend Date with respect

to new rights, options or warrants with such rights (in which case the existing rights, options or warrants shall be deemed to terminate

and expire on such date without exercise by any of the holders thereof). In addition, in the event of any distribution (or deemed distribution)

of rights, options or warrants, or any Trigger Event or other event (of the type described in the immediately preceding sentence) with

respect thereto that was counted for purposes of calculating a distribution amount for which an adjustment to the Conversion Rate under

this ‎Section 14.04(c) was made, (1) in the case of any such rights, options or warrants that shall all have been

redeemed or purchased without exercise by any holders thereof, upon such final redemption or purchase (x) the Conversion Rate shall

be readjusted as if such rights, options or warrants had not been issued and (y) the Conversion Rate shall then again be readjusted

to give effect to such distribution, deemed distribution or Trigger Event, as the case may be, as though it were a cash distribution,

equal to the per share redemption or purchase price received by a holder or holders of Common Stock with respect to such rights, options

or warrants (assuming such holder had retained such rights, options or warrants), made to all holders of Common Stock as of the date

of such redemption or purchase, and (2) in the case of such rights, options or warrants that shall have expired or been terminated

without exercise by any holders thereof, the Conversion Rate shall be readjusted as if such rights, options and warrants had not been

issued.

For purposes of ‎Section 14.04(a), ‎Section 14.04(b) and

this ‎Section 14.04(c), if any dividend or distribution to which this ‎Section 14.04(c) is applicable also

includes one or both of:

(A)            a

dividend or distribution of shares of Common Stock to which ‎Section 14.04(a) is applicable (the “Clause A Distribution”);

(B)            a

dividend or distribution of rights, options or warrants to which ‎Section 14.04(b) is applicable (the “Clause

B Distribution”),

then, in either case, (1) such dividend or distribution, other

than the Clause A Distribution and the Clause B Distribution, shall be deemed to be a dividend or distribution to which this ‎Section 14.04(c) is

applicable (the “Clause C Distribution”) and any Conversion Rate adjustment required by this ‎Section 14.04(c) with

respect to such Clause C Distribution shall then be made, and (2) the Clause A Distribution and Clause B Distribution shall be

deemed to immediately follow the Clause C Distribution and any Conversion Rate adjustment required by ‎Section 14.04(a) and

‎Section 14.04(b) with respect thereto shall then be made, except that, if determined by the Company (I) the “Ex-Dividend

Date” of the Clause A Distribution and the Clause B Distribution shall be deemed to be the Ex-Dividend Date of the Clause C Distribution

and (II) any shares of Common Stock included in the Clause A Distribution or Clause B Distribution shall be deemed not to be “outstanding

immediately prior to the open of business on such Ex-Dividend Date or Effective Date” within the meaning of ‎Section 14.04(a) or

“outstanding immediately prior to the open of business on such Ex-Dividend Date” within the meaning of ‎Section 14.04(b).

(d)            If

any dividend or distribution paid exclusively in cash is made to all or substantially all holders of the Common Stock, (other than any

dividends or distributions of any Reference Property consisting of cash upon conversion of, or in exchange for, the Common Stock in a

Share Exchange Event), the Conversion Rate shall be adjusted based on the following formula:

where,

CR0 =

the Conversion Rate in effect

immediately prior to the open of business on the Ex-Dividend Date for such dividend or distribution;

CR' =

the Conversion Rate in effect immediately after the open of business on the Ex-Dividend

Date for such dividend or distribution;

SP0 =

the Last Reported Sale Price of

the Common Stock on the Trading Day immediately preceding the Ex-Dividend Date for such dividend

or distribution; and

C =

the amount in cash per share the Company distributes to all or substantially all holders

of the Common Stock.

Any increase pursuant to this ‎Section 14.04(d) shall

become effective immediately after the open of business on the Ex-Dividend Date for such dividend or distribution. If such dividend or

distribution is not so paid, the Conversion Rate shall be decreased, effective as of the date the Board of Directors determines not to

make or pay such dividend or distribution, to be the Conversion Rate that would then be in effect if such dividend or distribution had

not been declared. Notwithstanding the foregoing, if “C” (as defined above) is equal to or greater than “SP0”

(as defined above), in lieu of the foregoing increase, each Holder of a Note shall receive, for each $1,000 principal amount of Notes,

at the same time and upon the same terms as holders of shares of the Common Stock and without having to convert its Notes, the amount

of cash that such Holder would have received if such Holder owned a number of shares of Common Stock equal to the Conversion Rate on

the Ex-Dividend Date for such cash dividend or distribution.

(e)            If

the Company or any of its Subsidiaries make a payment in respect of a tender or exchange offer for the Common Stock that is subject to

the then-applicable tender offer rules under the Exchange Act, other than an odd-lot tender offer, to the extent that the cash

and value of any other consideration included in the payment per share of the Common Stock exceeds the average of the Last Reported Sale

Prices of the Common Stock over the 10 consecutive Trading Day period commencing on, and including, the Trading Day next succeeding the

last date on which tenders or exchanges may be made pursuant to such tender or exchange offer, the Conversion Rate shall be increased

based on the following formula:

where,

CR0 =

the Conversion Rate in effect

immediately prior to the close of business on the 10th Trading Day immediately following,

and including, the Trading Day next succeeding the date such tender or exchange offer expires;

CR' =

the Conversion Rate in effect immediately after the close of business on the 10th

Trading Day immediately following, and including, the Trading Day next succeeding the date such tender

or exchange offer expires;

AC =

the aggregate value of all cash and any other consideration (as determined by the

Company in good faith) paid or payable for shares of Common Stock purchased in such tender or exchange offer;

OS0 =

the number of shares of Common

Stock outstanding immediately prior to the date such tender or exchange offer expires (prior

to giving effect to the purchase of all shares of Common Stock accepted for purchase or exchange

in such tender or exchange offer);

OS' =

the number of shares of Common Stock outstanding immediately after the date such

tender or exchange offer expires (after giving effect to the purchase of all shares of Common Stock accepted

for purchase or exchange in such tender or exchange offer); and

SP' =

the average of the Last Reported Sale Prices of the Common Stock over the 10 consecutive

Trading Day period commencing on, and including, the Trading Day next succeeding the date such tender or

exchange offer expires.

The increase to the Conversion Rate under this

‎Section 14.04(e) shall occur at the close of business on the 10th Trading Day immediately following, and including,

the Trading Day next succeeding the date such tender or exchange offer expires; provided that (x) in respect of any conversion

of Notes for which Physical Settlement is applicable, if the relevant Conversion Date occurs during the 10 Trading Days immediately following,

and including, the Trading Day next succeeding the expiration date of any tender or exchange offer, references to “10” or

“10th” in the preceding paragraph shall be deemed replaced with such lesser number of Trading Days as have elapsed from,

and including, the Trading Day next succeeding the date that such tender or exchange offer expires to, and including, the Conversion

Date in determining the Conversion Rate and (y) in respect of any conversion of Notes for which Cash Settlement or Combination

Settlement is applicable, for any Trading Day that falls within the relevant Observation Period for such conversion and within the 10

Trading Days immediately following, and including, the Trading Day next succeeding the expiration date of any tender or exchange offer,

references to “10” or “10th” in the preceding paragraph shall be deemed replaced with such lesser number of Trading

Days as have elapsed from, and including, the Trading Day next succeeding the expiration date of such tender or exchange offer to, and

including, such Trading Day in determining the Conversion Rate as of such Trading Day.

If the Company is, or one of the Company’s

Subsidiaries is, obligated to purchase the Common Stock pursuant to any such tender or exchange offer described in this ‎Section 14.04(e) but

the Company is, or such Subsidiary is, permanently prevented by applicable law from effecting any such purchase or all such purchases

are rescinded, the applicable Conversion Rate shall be decreased to be the Conversion Rate that would then be in effect if such tender

or exchange offer had not been made or had been made only in respect of the purchases that have been effected.

(f)            Notwithstanding

this ‎Section 14.04 or any other provision of this Indenture or the Notes, if (i) a Conversion Rate adjustment becomes

effective on any Ex-Dividend Date, (ii) a Note is to be converted for which Physical Settlement or Combination Settlement applies,

(iii) the Conversion Date for such conversion (in the case of Physical Settlement) or any Trading Day in the Observation Period

for such conversion (in the case of Combination Settlement) occurs on or after such Ex-Dividend Date and on or prior to the related Record

Date, (iv) the consideration due upon such conversion (in the case of Physical Settlement) or due with respect to such Trading

Day in the Observation Period (in the case of Combination Settlement) includes any whole shares of Common Stock based on a Conversion

Rate that is adjusted for such Ex-Dividend Date, and (v) such shares of Common Stock would be entitled to participate in such dividend,

distribution or other event giving rise to such adjustment, then, notwithstanding the Conversion Rate adjustment provisions in this ‎Section 14.04,

(x) in the case of Physical Settlement, the Conversion Rate adjustment relating to such Ex-Dividend Date shall not be made for

such conversion, and, instead, the shares of Common Stock issuable upon conversion on an unadjusted basis shall be entitled to participate

in the related dividend, distribution or other event giving rise to such adjustment, and (y) in the case of Combination Settlement,

the Conversion Rate adjustment relating to such Ex-Dividend Date shall be made for such conversion in respect of such Trading Day in

the Observation Period, but the shares of Common Stock issuable with respect to such Trading Day based on such adjusted Conversion Rate

shall not be entitled to participate in such dividend, distribution or other event giving rise to such adjustment.

(g)            Except

as stated herein, the Company shall not adjust the Conversion Rate for the issuance of shares of the Common Stock or any securities convertible

into or exchangeable for shares of the Common Stock or the right to purchase shares of the Common Stock or such convertible or exchangeable

securities.

(h)            In

addition to those adjustments required by clauses ‎(a), ‎(b), ‎(c), ‎(d) and ‎(e) of this ‎Section 14.04,

and to the extent permitted by applicable law and subject to the applicable rules of The Nasdaq Global Select Market, the Company

from time to time may increase the Conversion Rate by any amount for a period of at least 20 Business Days if the Board of Directors

determines that such increase would be in the Company’s best interest. In addition, to the extent permitted by applicable law and

subject to the applicable rules of The Nasdaq Global Select Market, the Company may (but is not required to) increase the Conversion

Rate to avoid or diminish any income tax to holders of Common Stock or rights to purchase Common Stock in connection with a dividend

or distribution of shares of Common Stock (or rights to acquire shares of Common Stock) or similar event. Whenever the Conversion Rate

is increased pursuant to either of the preceding two sentences, the Company shall give written notice to the Trustee and Conversion Agent

(if other than the Trustee) and deliver to the Holder of each Note a notice of the increase at least 15 days prior to the date the increased

Conversion Rate takes effect, and such notice shall state the increased Conversion Rate and the period during which it will be in effect.

(i)            Notwithstanding

anything to the contrary in this ‎Article 14, the Conversion Rate shall not be adjusted:

(i)            upon

the repurchase of shares of Common Stock pursuant to an open market share repurchase program or other buy-back transactions, including

structured or derivative transactions, such as accelerated share repurchase transactions or similar forward derivative, that is not a

tender or exchange offer described in ‎Section 14.04(e);

(ii)            upon

the issuance of shares of Common Stock at a price below the Conversion Price or otherwise, other than any such issuance described in

clause ‎(a), ‎(b) or ‎(c) of this ‎Section 14.04;

(iii)            upon

the issuance of any shares of Common Stock pursuant to any present or future plan providing for the reinvestment of dividends or interest

payable on the Company’s securities and the investment of additional optional amounts in shares of Common Stock under any plan;

(iv)            upon

the issuance of any shares of Common Stock or options or rights to purchase those shares pursuant to any present or future employee,

director or consultant benefit or incentive plan (including pursuant to an evergreen plan) or program of or assumed by the Company or

any of the Company’s Subsidiaries or in connection with any such shares withheld by the Company for tax withholding purposes;

(v)            upon

the issuance of any shares of the Common Stock pursuant to any option, warrant, right or exercisable, exchangeable or convertible security

not described in clause ‎(iv) of this subsection and outstanding as of the date the Notes were first issued;

(vi)            for

a tender or exchange offer by any party other than a tender or exchange offer by the Company or one or more of the Company’s Subsidiaries

described in ‎Section 14.04(e);

(vii)            solely

for a change in the par value (or lack of par value) of the Common Stock; or

(viii)            for

accrued and unpaid Special Interest, if any.

(j)            Notwithstanding

this ‎Section 14.04 or any other provisions of this Indenture, the Company shall not adjust the Conversion Rate pursuant to

any section in this ‎Section 14.04 unless the adjustment would result in a change of at least 1% in the then-effective Conversion

Rate; provided that the Company shall carry forward any adjustment to the Conversion Rate that the Company would otherwise have

to make and take that adjustment into account in any subsequent adjustment; provided further that all such carried-forward adjustments

shall be made with respect to Notes (i) in connection with any subsequent adjustment to the Conversion Rate of at least 1% of the

Conversion Rate, (ii) regardless of whether the aggregate adjustment is less than 1% of the Conversion Rate (x) on the Conversion

Date for any Notes (in the case of Physical Settlement or any conversion following a replacement of the Common Stock by Reference Property

consisting solely of cash) or (y) on each Trading Day of any Observation Period (in the case of Cash Settlement or Combination

Settlement), (iii) on any Effective Date for any Fundamental Change and/or Make-Whole Fundamental Change and (iv) on June 15

of each calendar year on or prior to the Maturity Date, in each case, unless the adjustment has already been made.

(k)            All

calculations and other determinations under this ‎Article 14 shall be made by the Company and shall be made to the nearest

one-ten thousandth (1/10,000th) of a share.

(l)            Whenever

the Conversion Rate is adjusted as herein provided, the Company shall promptly file with the Trustee (and the Conversion Agent if not

the Trustee) an Officers’ Certificate setting forth the Conversion Rate after such adjustment and setting forth a brief statement

of the facts requiring such adjustment. Unless and until a Responsible Officer of the Trustee and Conversion Agent (if not the Trustee)

shall have received such Officers’ Certificate, the Trustee and Conversion Agent shall not be deemed to have knowledge of any adjustment

of the Conversion Rate and may assume without inquiry that the last Conversion Rate of which it has knowledge is still in effect. Promptly

after delivery of such certificate, the Company shall prepare a notice of such adjustment of the Conversion Rate setting forth the adjusted

Conversion Rate and the date on which each adjustment becomes effective and shall deliver such notice of such adjustment of the Conversion

Rate to each Holder. Failure to deliver such notice shall not affect the legality or validity of any such adjustment.

(m)            For

purposes of this ‎Section 14.04, the number of shares of Common Stock at any time outstanding shall not include shares of Common

Stock held in the treasury of the Company so long as the Company does not pay any dividend or make any distribution on shares of Common

Stock held in the treasury of the Company, but shall include shares of Common Stock issuable in respect of scrip certificates issued

in lieu of fractions of shares of Common Stock.

Section 14.05. Adjustments of Prices.

Whenever any provision of this Indenture requires the Company to calculate the Last Reported Sale Prices, the Daily VWAPs, the Daily

Conversion Values or the Daily Settlement Amounts over a span of multiple days (including, without limitation, an Observation Period

and the period for determining the Stock Price for purposes of a Make-Whole Fundamental Change or Optional Redemption), the Company,

in good faith, shall make appropriate adjustments without duplication in respect of any adjustment made pursuant to ‎Section 14.04

to each to account for any adjustment to the Conversion Rate that becomes effective, or any event requiring an adjustment to the Conversion

Rate where the Ex-Dividend Date, Effective Date or expiration date, as the case may be, of the event occurs, at any time during the period

when the Last Reported Sale Prices, the Daily VWAPs, the Daily Conversion Values or the Daily Settlement Amounts are to be calculated.

Section 14.06. Shares to Be Fully Paid.

The Company shall provide, free from preemptive rights, out of its authorized but unissued shares or shares held in treasury, sufficient

shares of Common Stock to provide for conversion of the Notes from time to time as such Notes are presented for conversion (assuming

delivery of the maximum number of Additional Shares pursuant to ‎Section 14.03 and that at the time of computation of such

number of shares, all such Notes would be converted by a single Holder and that Physical Settlement were applicable).

Section 14.07. Effect of Recapitalizations,

Reclassifications and Changes of the Common Stock.

(a)            In

the case of:

(i)            any

recapitalization, reclassification or change of the Common Stock (other than a change to par value, or from par value to no par value,

or changes resulting from a subdivision or combination),

(ii)            any

consolidation, merger, combination or similar transaction involving the Company,

(iii)            any

sale, lease or other transfer to a third party of the consolidated assets of the Company and the Company’s Subsidiaries substantially

as an entirety or

(iv)            any

statutory share exchange,

in each case, as a result of which the Common Stock would be converted

into, or exchanged for, stock, other securities, other property or assets (including cash or any combination thereof) (any such event,

a “Share Exchange Event”), then, at and after the effective time of such Share Exchange Event, the right to convert

each $1,000 principal amount of Notes shall be changed into a right to convert such principal amount of Notes into the kind and amount

of shares of stock, other securities or other property or assets (including cash or any combination thereof) that a holder of a number

of shares of Common Stock equal to the Conversion Rate immediately prior to such Share Exchange Event would have owned or been entitled

to receive (the “Reference Property,” with each “unit of Reference Property” meaning the kind and

amount of Reference Property that a holder of one share of Common Stock is entitled to receive) upon such Share Exchange Event and, prior

to or at the effective time of such Share Exchange Event, the Company or the successor or purchasing Person, as the case may be, shall

execute with the Trustee, and without the consent of the Holders, a supplemental indenture permitted under ‎Section 10.01(g) providing

for such change in the right to convert each $1,000 principal amount of Notes; provided, however, that at and after the

effective time of the Share Exchange Event (A) the Company shall continue to have the right to determine the form of consideration

to be paid or delivered, as the case may be, upon conversion of Notes in accordance with ‎Section 14.02 and (B) (I) any

amount payable in cash upon conversion of the Notes in accordance with ‎Section 14.02 shall continue to be payable in cash,

(II) any shares of Common Stock that the Company would have been required to deliver upon conversion of the Notes in accordance

with ‎Section 14.02 shall instead be deliverable in the amount and type of Reference Property that a holder of that number

of shares of Common Stock would have been entitled to receive in such Share Exchange Event and (III) the Daily VWAP or the Last

Reported Sale Price of any unit of Reference Property or portion thereof that does not consist of a class of securities shall be the

fair value of such unit of Reference Property or portion thereof, as applicable, as determined in good faith by the Company (or in the

case of cash denominated in U.S. dollars, the face amount thereof).

If the Share Exchange Event causes the Common

Stock to be converted into, or exchanged for, the right to receive more than a single type of consideration (determined based in part

upon any form of stockholder election), then (i) the Reference Property into which the Notes will be convertible shall be deemed

to be the weighted average of the types and amounts of consideration actually received by the holders of Common Stock, and (ii) the

unit of Reference Property for purposes of the immediately preceding paragraph shall refer to the consideration referred to in clause

(i) attributable to one share of Common Stock. If the holders of the Common Stock receive only cash in such Share Exchange Event,

then for all conversions for which the relevant Conversion Date occurs after the effective date of such Share Exchange Event (A) the

consideration due upon conversion of each $1,000 principal amount of Notes shall be solely cash in an amount equal to the Conversion

Rate in effect on the Conversion Date (as may be increased by any Additional Shares pursuant to ‎Section 14.03), multiplied

by the price paid per share of Common Stock in such Share Exchange Event and (B) the Company shall satisfy the Conversion Obligation

by paying cash to converting Holders on the second Business Day immediately following the relevant Conversion Date. The Company shall

notify Holders, the Trustee and the Conversion Agent (if other than the Trustee) in writing of such weighted average as soon as practicable

after such determination is made.

Such supplemental indenture described in the second

immediately preceding paragraph shall provide for anti-dilution and other adjustments that shall be as nearly equivalent as is possible

to the adjustments provided for in this ‎Article 14. If, in the case of any Share Exchange Event, the Reference Property includes

shares of stock, securities or other property or assets (including cash or any combination thereof) of a Person other than the successor

or purchasing corporation, as the case may be, in such Share Exchange Event, then such supplemental indenture shall also be executed

by such other Person and shall contain such additional provisions to protect the interests of the Holders of the Notes as the Board of

Directors shall reasonably consider necessary by reason of the foregoing, including the provisions providing for the purchase rights

set forth in ‎Article 15.

(b)            When

the Company executes a supplemental indenture pursuant to subsection ‎(a) of this ‎Section 14.07, the Company shall

promptly file with the Trustee an Officers’ Certificate briefly stating the reasons therefor, the kind or amount of cash, securities

or property or asset that will comprise a unit of Reference Property after any such Share Exchange Event, any adjustment to be made with

respect thereto and that all conditions precedent have been complied with and shall promptly deliver or cause to be delivered notice

thereof to all Holders. The Company shall cause notice of the execution of such supplemental indenture to be delivered to each Holder

within 20 days after execution thereof. Failure to deliver such notice shall not affect the legality or validity of such supplemental

indenture.

of the foregoing provisions shall affect the right of a holder of Notes to convert its Notes into cash, shares of Common Stock or a combination

of cash and shares of Common Stock, as applicable, as set forth in ‎Section 14.01 and ‎Section 14.02 prior to the

effective date of such Share Exchange Event.

(d)            The

above provisions of this Section shall similarly apply to successive Share Exchange Events.

Section 14.08. Certain Covenants.

(a) The Company covenants that all shares of Common Stock issued upon conversion of Notes will be fully paid and non-assessable

by the Company and free from all taxes, liens and charges with respect to the issue thereof.

(b)            The

Company covenants that, if any shares of Common Stock to be provided for the purpose of conversion of Notes hereunder require registration

with or approval of any governmental authority under any federal or state law before such shares of Common Stock may be validly issued

upon conversion, the Company will, to the extent then permitted by the rules and interpretations of the Commission, secure such

registration or approval, as the case may be.

Company further covenants that if at any time the Common Stock shall be listed on any national securities exchange or automated quotation

system the Company will list and use commercially reasonably efforts to keep listed, so long as the Common Stock shall be so listed on

such exchange or automated quotation system, any Common Stock issuable upon conversion of the Notes.

Section 14.09. Responsibility of Trustee.

The Trustee and any other Conversion Agent shall not at any time be under any duty or responsibility to any Holder to determine the Conversion

Rate (or any adjustment thereto) or whether any facts exist that may require any adjustment (including any increase) of the Conversion

Rate, or with respect to the nature or extent or calculation of any such adjustment when made, or with respect to the method employed,

or herein or in any supplemental indenture provided to be employed, in making the same. The Trustee and any other Conversion Agent shall

not be accountable with respect to the validity or value (or the kind or amount) of any shares of Common Stock, or of any securities,

property or cash that may at any time be issued or delivered upon the conversion of any Note; and the Trustee and any other Conversion

Agent make no representations with respect thereto. Neither the Trustee nor any Conversion Agent shall be responsible for any failure

of the Company to issue, transfer or deliver any shares of Common Stock or stock certificates or other securities or property or cash

upon the surrender of any Note for the purpose of conversion or to comply with any of the duties, responsibilities or covenants of the

Company contained in this Article. Without limiting the generality of the foregoing, neither the Trustee nor any Conversion Agent shall

be under any responsibility to determine the correctness of any provisions contained in any supplemental indenture entered into pursuant

to ‎Section 14.07 relating either to the kind or amount of shares of stock or securities or property (including cash) receivable

by Holders upon the conversion of their Notes after any event referred to in such ‎Section 14.07 or to any adjustment to be

made with respect thereto, but, subject to the provisions of ‎Section 7.01, may accept (without any independent investigation)

as conclusive evidence of the correctness of any such provisions, and shall be protected in relying upon, the Officers’ Certificate

(which the Company shall be obligated to file with the Trustee prior to the execution of any such supplemental indenture) with respect

thereto. Neither the Trustee nor the Conversion Agent shall be responsible for determining whether any event contemplated by ‎Section 14.01(b) has

occurred that makes the Notes eligible for conversion or no longer eligible therefor until the Company has delivered to the Trustee and

the Conversion Agent the notices referred to in ‎Section 14.01(b) with respect to the commencement or termination of

such conversion rights, on which notices the Trustee and the Conversion Agent may conclusively rely, and the Company agrees to deliver

such notices to the Trustee and the Conversion Agent immediately after the occurrence of any such event or at such other times as shall

be provided for in ‎Section 14.01(b). Neither the Trustee nor the Conversion Agent shall have any obligation to make any calculation

or to determine whether the Notes may be surrendered for conversion pursuant to this Indenture, or to notify the Company or the Depositary

or any of the Holders if the Notes have become convertible pursuant to the terms of this Indenture, or to otherwise independently determine

or verify if any Fundamental Change, Make-Whole Fundamental Change, Share Exchange Event, Trigger Event, or any other event has occurred

or notify the Holders of any such event. Neither the Trustee nor Conversion Agent shall have the responsibility for any act or omission

of any Designated Financial Institution.

Section 14.10. [Reserved].

Section 14.11. Stockholder Rights Plans.

If the Company has a stockholder rights plan in effect upon conversion of the Notes, each share of Common Stock, if any, issued upon

such conversion shall be entitled to receive the appropriate number of rights, if any, and the certificates representing the Common Stock

issued upon such conversion shall bear such legends, if any, in each case as may be provided by the terms of any such stockholder rights

plan, as the same may be amended from time to time. However, if, prior to any conversion of Notes, the rights have separated from the

shares of Common Stock in accordance with the provisions of the applicable stockholder rights plan, the Conversion Rate shall be adjusted

at the time of separation as if the Company distributed to all or substantially all holders of the Common Stock Distributed Property

as provided in ‎Section 14.04(c), subject to readjustment in the event of the expiration, termination or redemption of such

rights.

Section 14.12. Exchange In Lieu Of Conversion.

(a) When a Holder surrenders its Notes for conversion, the Company may, at its election (an “Exchange Election”),

cause such Notes to be delivered to one or more financial institutions designated by the Company (each, a “Designated Financial

Institution”) for exchange in lieu of conversion. In order to accept any Notes surrendered for conversion, the Designated Financial

Institution(s) must agree in writing to timely pay and/or deliver, as the case may be, in exchange for such Notes, the amount of

cash, number of shares of Common Stock or any combination thereof, at the Company’s election, that would otherwise be due upon

conversion pursuant to ‎Section 14.02 (the “Conversion Consideration”). If the Company makes an Exchange

Election, the Company shall, before the close of business on the Business Day immediately following the relevant Conversion Date, notify

in writing the Trustee, the Conversion Agent (if other than the Trustee) and the Holder surrendering its Notes for conversion that the

Company has made the Exchange Election and the Company shall notify the Designated Financial Institution(s), the Trustee and the Conversion

Agent (if other than the Trustee) of the relevant deadline for payment and/or delivery of the Conversion Consideration. If the Company

makes an Exchange Election, no later than the second Business Day immediately following the relevant Conversion Date, the Company shall

deliver (or cause the Conversion Agent to deliver) the Notes surrendered for exchange to the Designated Financial Institution(s) in

lieu of conversion. The Company, the Holder surrendering the Notes for conversion, the Designated Financial Institution(s) and

the Conversion Agent shall cooperate to cause such Notes to be delivered to the Designated Financial Institution(s) and the Conversion

Agent shall be entitled to conclusively rely upon the Company’s instruction in connection with effecting any Exchange Election

and shall have no liability for such Exchange Election outside its control.

(b)            Any

Notes exchanged by the Designated Financial Institution(s) shall remain outstanding notwithstanding the surrender of such Notes,

subject to applicable procedures of the Depositary. If the Designated Financial Institution(s) agree(s) to accept any Notes

for exchange but does not timely pay and/or deliver, as the case may be, the related Conversion Consideration, or if such Designated

Financial Institution does not accept the Notes for exchange, the Company shall notify the Conversion Agent and the Holders surrendering

the Notes for conversion in writing and shall pay and/or deliver, as the case may be, the relevant Conversion Consideration as if the

Company had not made the Exchange Election.

Company’s designation of any Designated Financial Institution(s) to which the Notes may be submitted for exchange does not

require such Designated Financial Institution(s) to accept any Notes and in such case, the Company shall notify the Conversion

Agent of such refusal by the Designated Financial Institution(s).

Article 15

Repurchase of Notes at Option of Holders

Section 15.01. [Intentionally Omitted]

Section 15.02. Repurchase at Option of

Holders Upon a Fundamental Change. (a)  If a Fundamental Change occurs at any time prior to the Maturity Date, each Holder

shall have the right, at such Holder’s option, to require the Company to repurchase for cash all of such Holder’s Notes,

or any portion thereof that is equal to minimum denominations of $1,000 or an integral multiple of $1,000 in excess thereof, on the date

(the “Fundamental Change Repurchase Date”) specified by the Company that is not less than 20 calendar days or more

than 35 calendar days following the date of the Fundamental Change Company Notice at a repurchase price equal to 100% of the principal

amount thereof, plus accrued and unpaid Special Interest, if any, thereon to, but excluding, the Fundamental Change Repurchase

Date (the “Fundamental Change Repurchase Price”), unless the Fundamental Change Repurchase Date falls after a Special

Interest Record Date but on or prior to the Special Interest Payment Date to which such Special Interest Record Date relates, in which

case the Company shall instead pay the full amount of any accrued and unpaid Special Interest (to, but excluding, such Special Interest

Payment Date) to Holders of record as of such Special Interest Record Date, and the Fundamental Change Repurchase Price shall be equal

to 100% of the principal amount of Notes to be repurchased pursuant to this ‎Article 15; provided that the Company shall

not be required to repurchase, or to make an offer to repurchase, the Notes upon a Fundamental Change if a third party makes such an

offer in the same manner, at the same time and otherwise in compliance with the requirements for an offer made by the Company as set

forth in this ‎Section 15.02 and such third party purchases all Notes properly surrendered and not validly withdrawn under

its offer in the same manner, at the same time and otherwise in compliance with the requirements for an offer made by the Company as

set forth in this ‎Section 15.02.

(b)            Repurchases

of Notes under this ‎Section 15.02 shall be made, at the option of the Holder thereof, upon:

(i)            delivery

to the Paying Agent or tender agent appointed to facilitate the repurchase (the “Tender Agent”) by a Holder of a duly

completed notice (the “Fundamental Change Repurchase Notice”) in the form set forth in Attachment 2 to the Form of

Note attached hereto as Exhibit A, if the Notes are Physical Notes, or in compliance with the Depositary’s procedures for

surrendering interests in Global Notes, if the Notes are Global Notes, in each case on or before the close of business on the Business

Day immediately preceding the Fundamental Change Repurchase Date; and

(ii)            delivery

of the Notes, if the Notes are Physical Notes, to the Paying Agent or Tender Agent, as the case may be, at any time after delivery of

the Fundamental Change Repurchase Notice (together with all necessary endorsements for transfer) at the Corporate Trust Office of the

Paying Agent or the principal office of the Tender Agent located in the United States of America as notified by the Tender Agent to Holders

and the Trustee, as applicable, or book-entry transfer of the Notes, if the Notes are Global Notes, in compliance with the procedures

of the Depositary, in each case such delivery being a condition to receipt by the Holder of the Fundamental Change Repurchase Price therefor.

The Fundamental Change Repurchase Notice in respect

of any Notes to be repurchased shall state:

(i)            in

the case of Physical Notes, the certificate numbers of the Notes to be delivered for repurchase;

(ii)            the

portion of the principal amount of Notes to be repurchased, which must be $1,000 or an integral multiple in excess thereof; and

(iii)            that

the Notes are to be repurchased by the Company pursuant to the applicable provisions of the Notes and this Indenture;

provided, however,

that if the Notes are Global Notes, the Fundamental Change Repurchase Notice must comply with appropriate Depositary procedures.

Notwithstanding anything herein to the contrary,

any Holder delivering to the Paying Agent or Tender Agent, as the case may be, the Fundamental Change Repurchase Notice contemplated

by this ‎Section 15.02 shall have the right to withdraw, in whole or in part, such Fundamental Change Repurchase Notice at

any time prior to the close of business on the Business Day immediately preceding the Fundamental Change Repurchase Date by delivery

of a written notice of withdrawal to the Paying Agent or Tender Agent, as the case may be, in accordance with ‎Section 15.03,

or in accordance with the customary procedures of the Depository with respect to Global Notes.

The Paying Agent or Tender Agent, as the case

may be, shall promptly notify the Company of the receipt by it of any Fundamental Change Repurchase Notice or written notice of withdrawal

thereof.

or before the 20th Business Day after the occurrence of the effective date of a Fundamental Change, the Company shall provide to all

Holders of Notes and the Trustee, the Conversion Agent (in the case of a Conversion Agent other than the Trustee) and the Paying Agent

(in the case of a Paying Agent other than the Trustee) a notice (the “Fundamental Change Company Notice”) of the occurrence

of the effective date of the Fundamental Change and of the repurchase right at the option of the Holders arising as a result thereof.

In the case of Physical Notes, such notice shall be by first class mail or, in the case of Global Notes, such notice shall be delivered

in accordance with the applicable procedures of the Depositary. Simultaneously with providing such notice, the Company shall publish

a notice containing the information set forth in the Fundamental Change Company Notice on the Company’s website or through such

other public medium as the Company may use at that time. Each Fundamental Change Company Notice shall specify:

(i)            the

events causing the Fundamental Change;

(ii)            the

effective date of the Fundamental Change;

(iii)            the

last date on which a Holder may exercise the repurchase right pursuant to this ‎Article 15;

(iv)            the

Fundamental Change Repurchase Price;

(v)            the

Fundamental Change Repurchase Date;

(vi)            the

name and address of the Paying Agent or Tender Agent, as the case may be, and the Conversion Agent, if applicable;

(vii)            if

applicable, the Conversion Rate and any adjustments to the Conversion Rate as a result of the Fundamental Change;

(viii)            that

the Notes with respect to which a Fundamental Change Repurchase Notice has been delivered by a Holder may be converted only if the Holder

validly withdraws the Fundamental Change Repurchase Notice in accordance with the terms of this Indenture; and

(ix)            the

procedures that Holders must follow to require the Company to repurchase their Notes.

No failure of the Company to give the foregoing

notices and no defect therein shall limit the Holders’ repurchase rights or affect the validity of the proceedings for the repurchase

of the Notes pursuant to this ‎Section 15.02.

At the Company’s request, given at least

five days prior to the date the Fundamental Change Company Notice is to be sent (or such shorter period as may be agreed to by the Trustee),

the Trustee shall give such notice in the Company’s name and at the Company’s expense; provided, however, that,

in all cases, the text of such Fundamental Change Company Notice shall be prepared by the Company.

(d)            Notwithstanding

the foregoing, no Notes may be repurchased by the Company on any date at the option of the Holders upon a Fundamental Change if the principal

amount of the Notes has been accelerated, and such acceleration has not been rescinded, on or prior to such date (except in the case

of an acceleration resulting from a Default by the Company in the payment of the Fundamental Change Repurchase Price with respect to

such Notes). The Paying Agent or Tender Agent, as the case may be, will promptly return to the respective Holders thereof any Physical

Notes held by it during the acceleration of the Notes (except in the case of an acceleration resulting from a Default by the Company

in the payment of the Fundamental Change Repurchase Price with respect to such Notes), or any instructions for book-entry transfer of

the Notes in compliance with the procedures of the Depositary shall be deemed to have been cancelled, and, upon such return or cancellation,

as the case may be, the Fundamental Change Repurchase Notice with respect thereto shall be deemed to have been withdrawn.

Section 15.03. Withdrawal of Fundamental

Change Repurchase Notice. A Fundamental Change Repurchase Notice may be withdrawn (in whole or in part) by means of a written notice

of withdrawal received by the Corporate Trust Office of the Paying Agent or the principal office of the Tender Agent located in the United

States of America as notified by the Tender Agent to Holders and the Trustee, as the case may be, in accordance with this ‎Section 15.03

at any time prior to the close of business on the Business Day immediately preceding the Fundamental Change Repurchase Date, specifying:

(i)            the

principal amount of the Notes with respect to which such notice of withdrawal is being submitted,

(ii)            if

Physical Notes have been issued, the certificate number of the Note in respect of which such notice of withdrawal is being submitted,

and

(iii)            the

principal amount, if any, of such Note that remains subject to the original Fundamental Change Repurchase Notice, which portion must

be in principal amounts of $1,000 or an integral multiple of $1,000;

provided, however,

that if the Notes are Global Notes, the notice must comply with appropriate procedures of the Depositary.

Section 15.04. Deposit of Fundamental

Change Repurchase Price. (a)  The Company will deposit with the Trustee (or other Paying Agent or Tender Agent, as the case

may be, appointed by the Company, or if the Company is acting as its own Paying Agent, set aside, segregate and hold in trust as provided

in ‎Section 4.04) on or prior to 11:00 a.m., New York City time, on the Fundamental Change Repurchase Date an amount of money

sufficient to repurchase all of the Notes to be repurchased at the appropriate Fundamental Change Repurchase Price. Subject to receipt

of funds and/or Notes by the Trustee (or other Paying Agent or Tender Agent, as the case may be, appointed by the Company), payment for

Notes surrendered for repurchase (and not withdrawn prior to the close of business on the Business Day immediately preceding the Fundamental

Change Repurchase Date) will be made on the later of (i) the Fundamental Change Repurchase Date (provided the Holder has

satisfied the conditions in ‎Section 15.02) and (ii) the time of book-entry transfer or the delivery of such Note to

the Trustee (or other Paying Agent or Tender Agent, as the case may be, appointed by the Company) by the Holder thereof in the manner

required by ‎Section 15.02 by mailing checks for the amount payable to the Holders of such Notes entitled thereto as they shall

appear in the Note Register; provided, however, that payments to the Depositary shall be made by wire transfer of immediately

available funds to the account of the Depositary or its nominee. The Paying Agent or Tender Agent shall, promptly after such payment

and upon written demand by the Company, return to the Company any funds in excess of the Fundamental Change Repurchase Price.

(b)            If

by 11:00 a.m. New York City time, on the Fundamental Change Repurchase Date, the Trustee (or other Paying Agent or Tender Agent,

as the case may be, appointed by the Company) holds money sufficient to make payment on all the Notes or portions thereof that are to

be repurchased on such Fundamental Change Repurchase Date, then, with respect to the Notes that have been properly surrendered for repurchase

and have not been validly withdrawn, (i) such Notes will cease to be outstanding, (ii) Special Interest, if any, will cease

to accrue on such Notes (whether or not book-entry transfer of the Notes has been made or the Notes have been delivered to the Trustee,

Paying Agent or Tender Agent, as the case may be) and (iii) all other rights of the Holders of such Notes will terminate (other

than the right to receive the Fundamental Change Repurchase Price and, if applicable, any accrued and unpaid Special Interest).

surrender of a Note that is to be repurchased in part pursuant to ‎Section 15.02, the Company shall execute and the Trustee

shall authenticate and deliver to the Holder a new Note in an authorized denomination equal in principal amount to the unrepurchased

portion of the Note surrendered.

Section 15.05. Covenant to Comply with

Applicable Laws Upon Repurchase of Notes. In connection with any repurchase offer, the Company will, if required:

(a)            comply

with the provisions of Rule 13e-4, Rule 14e-1 and any other tender offer rules under the Exchange Act;

(b)            file

a Schedule TO or any other required schedule under the Exchange Act; and

comply with all federal and state securities laws in connection with any offer by the Company to repurchase the Notes;

in each case, so as to permit the rights and obligations under this

‎Article 15 to be exercised in the time and in the manner specified in this ‎Article 15. To the extent that the provisions

of any applicable securities laws or regulations enacted after the date of this Indenture conflict with the provisions of this Indenture

relating to the Company’s obligations to repurchase the Notes upon a Fundamental Change, the Company shall comply with the applicable

securities laws and regulations and shall not be deemed to have breached its obligations under such provisions of this Indenture by virtue

of such conflict.

Article 16

Optional Redemption

Section 16.01. Optional Redemption.

No sinking fund is provided for the Notes. The Notes shall not be redeemable by the Company prior to June 20, 2029. On or after

June 20, 2029, the Company may redeem (an “Optional Redemption”) for cash all or any portion of the Notes, at

the Redemption Price, if the Last Reported Sale Price of the Common Stock has been at least 130% of the Conversion Price then in effect

for at least 20 Trading Days (whether or not consecutive) during any 30 consecutive Trading Day period (including the last Trading Day

of such period) ending on, and including, the Trading Day immediately preceding the date on which the Company provides the Redemption

Notice in accordance with ‎Section 16.02. The Trustee shall have no liability or responsibility for determining whether the

conditions to redemption have been met.

Section 16.02. Notice of Optional Redemption;

Selection of Notes. (a)  In case the Company exercises its Optional Redemption right to redeem all or, as the case may be,

any part of the Notes pursuant to ‎Section 16.01, it shall fix a date for redemption (each, a “Redemption Date”)

and it or, at its written request received by the Trustee not less than five days prior to the date the Redemption Notice is to be sent

to Holders (or such shorter period of time as may be acceptable to the Trustee), the Trustee, in the name of and at the expense of the

Company, shall deliver or cause to be delivered a written notice of such Optional Redemption (a “Redemption Notice”)

not less than 30 nor more than 50 Scheduled Trading Days prior to the Redemption Date by mail or electronic transmission to each Holder

of Notes so to be redeemed as a whole or in part; provided, however, that, if the Company shall give such notice, it shall

also give written notice of the Redemption Date to the Trustee, the Paying Agent and the Conversion Agent (if other than the Trustee).

The Redemption Date must be a Business Day, and the Company shall not specify a Redemption Date that falls on or after the 26th Scheduled

Trading Day immediately preceding the Maturity Date. The Trustee is permitted to accept the Company’s direction regarding redemptions,

notwithstanding anything to the contrary in this Indenture, and the Trustee shall have no liability for any action taken at the Company’s

direction.

(b)            The

Redemption Notice, if delivered in the manner herein provided, shall be conclusively presumed to have been duly given, whether or not

the Holder receives such notice. In any case, failure to give such Redemption Notice or any defect in the Redemption Notice to the Holder

of any Note designated for redemption as a whole or in part shall not affect the validity of the proceedings for the redemption of any

other Note.

Redemption Notice shall specify:

(i)            the

Redemption Date;

(ii)            the

Redemption Price;

(iii)            that

on the Redemption Date, the Redemption Price will become due and payable upon each Note to be redeemed, and that interest thereon, if

any, shall cease to accrue on and after the Redemption Date;

(iv)            the

place or places where such Notes are to be surrendered for payment of the Redemption Price;

(v)            that

Holders may surrender their Notes for conversion at any time prior to the close of business on the second Scheduled Trading Day immediately

preceding the Redemption Date;

(vi)            the

procedures a converting Holder must follow to convert its Notes and the Settlement Method and Specified Dollar Amount, if applicable;

(vii)            the

Conversion Rate and, if applicable, the number of Additional Shares added to the Conversion Rate in accordance with ‎Section 14.03;

(viii)            the

CUSIP, ISIN or other similar numbers, if any, assigned to such Notes; and

(ix)            in

case any Note is to be redeemed in part only, the portion of the principal amount thereof to be redeemed and on and after the Redemption

Date, upon surrender of such Note, a new Note in principal amount equal to the unredeemed portion thereof shall be issued.

A Redemption Notice shall be irrevocable.

(d)            If

fewer than all of the outstanding Notes are to be redeemed and the Notes to be redeemed are Global Notes then held by the Depositary,

the Notes to be redeemed shall be selected by the Depositary in accordance with applicable procedures of the Depositary. If fewer than

all of the outstanding Notes are to be redeemed and the Notes to be redeemed are not Global Notes then held by the Depositary, the Trustee

shall select the Notes or portions thereof to be redeemed (in minimum principal amounts of $1,000 or multiples of $1,000 in excess thereof)

by lot, on a pro rata basis or by another method the Trustee considers to be fair and appropriate, subject to the Depositary’s

procedures. If any Note selected for partial redemption is submitted for conversion in part after such selection, the portion of the

Note submitted for conversion shall be deemed (so far as may be possible) to be the portion selected for redemption.

Section 16.03.

Payment of Notes Called for Redemption. (a)  If any Redemption Notice has been given in respect of the Notes in accordance

with ‎Section 16.02, the Notes shall become due and payable on the Redemption Date at the place or places stated in the Redemption

Notice and at the applicable Redemption Price. On presentation and surrender of the Notes at the place or places stated in the Redemption

Notice, the Notes shall be paid and redeemed by the Company at the applicable Redemption Price.

(b)            Prior

to the open of business on the Redemption Date, the Company shall deposit with the Paying Agent or, if the Company or a Subsidiary of

the Company is acting as the Paying Agent, shall segregate and hold in trust as provided in ‎Section 7.05 an amount of cash

(in immediately available funds if deposited on the Redemption Date), sufficient to pay the Redemption Price of all of the Notes to be

redeemed on such Redemption Date. Subject to receipt of funds by the Paying Agent, payment for the Notes to be redeemed shall be made

on the Redemption Date for such Notes. The Paying Agent shall, promptly after such payment and upon written demand by the Company, return

to the Company any funds in excess of the Redemption Price.

Section 16.04.

Restrictions on Redemption. The Company may not redeem any Notes on any date if the principal amount of the Notes has been

accelerated in accordance with the terms of this Indenture, and such acceleration has not been rescinded, on or prior to the Redemption

Date (except in the case of an acceleration resulting from a Default by the Company in the payment of the Redemption Price with respect

to such Notes).

Article 17

Miscellaneous Provisions

Section 17.01. Provisions Binding on

Company’s Successors. All the covenants, stipulations, promises and agreements of the Company contained in this Indenture shall

bind its successors and assigns whether so expressed or not.

Section 17.02. Official Acts by Successor

Corporation. Any act or proceeding by any provision of this Indenture authorized or required to be done or performed by any board,

committee or Officer of the Company shall and may be done and performed with like force and effect by the like board, committee or officer

of any corporation or other entity that shall at the time be the lawful sole successor of the Company.

Section 17.03. Addresses for Notices,

Etc. Any notice or demand that by any provision of this Indenture is required or permitted to be given or served by the Trustee or

by the Holders on the Company shall be deemed to have been sufficiently given or made, for all purposes if given or served by being deposited

postage prepaid by registered or certified mail in a post office letter box or overnight courier service addressed (until another address

is filed by the Company with the Trustee) to PTC Therapeutics, Inc., 500 Warren Corporate Center Drive, Warren, N.J. 07059. Any

notice, direction, request or demand hereunder to or upon the Trustee shall be deemed to have been sufficiently given or made, for all

purposes, if given or served by being deposited postage prepaid by registered or certified mail in a post office letter box, electronic

transmission or overnight delivery addressed to the Corporate Trust Office, whether sent by mail or electronically, upon actual receipt

by the Trustee.

The Trustee, by notice to the Company, may designate

additional or different addresses for subsequent notices or communications.

Any notice or communication delivered or to be

delivered to a Holder of Physical Notes shall be mailed to it by first class mail, postage prepaid, at its address as it appears on the

Note Register and shall be sufficiently given to it if so mailed within the time prescribed. Any notice or communication delivered or

to be delivered to a Holder of Global Notes shall be delivered in accordance with the applicable procedures of the Depositary and shall

be sufficiently given to it if so delivered within the time prescribed.

Failure to mail or deliver a notice or communication

to a Holder or any defect in it shall not affect its sufficiency with respect to other Holders. If a notice or communication is mailed

or delivered, as the case may be, in the manner provided above, it is duly given, whether or not the addressee receives it.

In case by reason of the suspension of regular

mail service or by reason of any other cause it shall be impracticable to give such notice to Holders by mail, then such notification

as shall be made with the approval of the Trustee shall constitute a sufficient notification for every purpose hereunder.

Section 17.04. Governing Law; Jurisdiction.

THIS INDENTURE AND EACH NOTE, AND ANY CLAIM, CONTROVERSY OR DISPUTE ARISING UNDER OR RELATED TO THIS INDENTURE AND EACH NOTE, SHALL BE

GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK.

The Company irrevocably consents and agrees, to

the extent permitted by applicable law, for the benefit of the Holders from time to time of the Notes and the Trustee, that any legal

action, suit or proceeding against it with respect to obligations, liabilities or any other matter arising out of or in connection with

this Indenture or the Notes may be brought in the courts of the State of New York or the courts of the United States located in the Borough

of Manhattan, New York City, New York and, until amounts due and to become due in respect of the Notes have been paid, hereby irrevocably

consents and submits, to the extent permitted by applicable law, to the jurisdiction of each such court in personam, generally

and unconditionally, to the extent permitted by applicable law, with respect to any action, suit or proceeding for itself in respect

of its properties, assets and revenues.

The Company irrevocably and unconditionally waives,

to the extent permitted by applicable law, any objection which it may now or hereafter have to the laying of venue of any of the aforesaid

actions, suits or proceedings arising out of or in connection with this Indenture brought in the courts of the State of New York or the

courts of the United States located in the Borough of Manhattan, New York City, New York and hereby further irrevocably and unconditionally

waives and agrees, to the extent permitted by applicable law, not to plead or claim in any such court that any such action, suit or proceeding

brought in any such court has been brought in an inconvenient forum.

Section 17.05. Evidence of Compliance

with Conditions Precedent; Certificates and Opinions of Counsel to Trustee. Upon any application or demand by the Company to the

Trustee to take any action under any of the provisions of this Indenture, the Company shall, if requested by the Trustee, furnish to

the Trustee an Officers’ Certificate and an Opinion of Counsel, stating that such action is permitted by the terms of this Indenture

and that all conditions precedent to such action have been complied with; provided that such Opinion of Counsel shall not be required

in connection with (1) the issuance of the Notes on the original issue date of the Notes, (2) the mandatory exchange of the

restricted CUSIP of the Notes to an unrestricted CUSIP pursuant to the applicable procedures of the Depositary upon the Notes becoming

freely tradable by non-Affiliates of the Company under Rule 144, or (3) a request by the Company that the Trustee deliver

a notice to Holders under this Indenture where the Trustee receives an Officers’ Certificate with respect to such notice. With

respect to matters of fact, an Opinion of Counsel may rely on an Officers’ Certificate or certificates of public officials.

Each Officers’ Certificate and Opinion of

Counsel provided for, by or on behalf of the Company in this Indenture and delivered to the Trustee with respect to compliance with this

Indenture (other than the Officers’ Certificates provided for in ‎Section 4.08) shall include (a) a statement that

the person signing such certificate is familiar with the requested action and this Indenture; (b) a brief statement as to the nature

and scope of the examination or investigation upon which the statement contained in such certificate is based; (c) a statement

that, in the opinion of such person, he or she has made such examination or investigation as is necessary to enable him or her to express

an informed opinion as to whether or not such action is permitted by this Indenture; and (d) a statement as to whether or not,

in the opinion of such person, such action is permitted by this Indenture and all conditions precedent to such action have been complied

with.

Section 17.06. Legal Holidays. In

any case where any Special Interest Payment Date, any Fundamental Change Repurchase Date, Redemption Date or the Maturity Date is not

a Business Day or is a day on which banks located in the location of the Corporate Trust Office are authorized or required by law or

executive order to close or be closed, then any action to be taken on such date need not be taken on such date, but may be taken on the

next succeeding Business Day that is not a day on which banks located in the location of the Corporate Trust Office are authorized or

required by law or executive order to close or be closed with the same force and effect as if taken on such date, and no interest shall

accrue in respect of the delay.

Section 17.07. No Security Interest Created.

Nothing in this Indenture or in the Notes, expressed or implied, shall be construed to constitute a security interest under the Uniform

Commercial Code or similar legislation, as now or hereafter enacted and in effect, in any jurisdiction.

Section 17.08. Benefits of Indenture.

Nothing in this Indenture or in the Notes, expressed or implied, shall give to any Person, other than the Holders, the parties hereto,

any Paying Agent, any Conversion Agent, any authenticating agent, any Note Registrar and their successors hereunder, any benefit or any

legal or equitable right, remedy or claim under this Indenture.

Section 17.09. Table of Contents, Headings,

Etc. The table of contents and the titles and headings of the articles and sections of this Indenture have been inserted for convenience

of reference only, are not to be considered a part hereof, and shall in no way modify or restrict any of the terms or provisions hereof.

Section 17.10. Authenticating Agent.

The Trustee may appoint an authenticating agent that shall be authorized to act on its behalf and subject to its direction in the authentication

and delivery of Notes in connection with the original issuance thereof and transfers and exchanges of Notes hereunder, including under

‎Section 2.04, ‎Section 2.05, ‎Section 2.06, ‎Section 2.07, ‎Section 10.04 and ‎Section 15.04

as fully to all intents and purposes as though the authenticating agent had been expressly authorized by this Indenture and those Sections

to authenticate and deliver Notes. For all purposes of this Indenture, the authentication and delivery of Notes by the authenticating

agent shall be deemed to be authentication and delivery of such Notes “by the Trustee” and a certificate of authentication

executed on behalf of the Trustee by an authenticating agent shall be deemed to satisfy any requirement hereunder or in the Notes for

the Trustee’s certificate of authentication. Such authenticating agent shall at all times be a Person eligible to serve as trustee

hereunder pursuant to ‎Section 7.08.

Any corporation or other entity into which any

authenticating agent may be merged or converted or with which it may be consolidated, or any corporation or other entity resulting from

any merger, consolidation or conversion to which any authenticating agent shall be a party, or any corporation or other entity succeeding

to all or substantially all the corporate trust business of any authenticating agent, shall be the successor of the authenticating agent

hereunder, if such successor corporation or other entity is otherwise eligible under this ‎Section 17.10, without the execution

or filing of any paper or any further act on the part of the parties hereto or the authenticating agent or such successor corporation

or other entity.

Any authenticating agent may at any time resign

by giving written notice of resignation to the Trustee and to the Company. The Trustee may at any time terminate the agency of any authenticating

agent by giving written notice of termination to such authenticating agent and to the Company. Upon receiving such a notice of resignation

or upon such a termination, or in case at any time any authenticating agent shall cease to be eligible under this Section, the Trustee

may appoint a successor authenticating agent (which may be the Trustee), shall give written notice of such appointment to the Company

and shall deliver notice of such appointment to all Holders.

The Company agrees to pay to the authenticating

agent from time to time reasonable compensation for its services although the Company may terminate the authenticating agent, if it determines

such agent’s fees to be unreasonable.

The provisions of ‎Section 7.02, ‎Section 7.03,

‎Section 7.04, ‎Section 8.03 and this ‎Section 17.10 shall be applicable to any authenticating agent.

If an authenticating agent is appointed pursuant

to this ‎Section 17.10, the Notes may have endorsed thereon, in addition to the Trustee’s certificate of authentication,

an alternative certificate of authentication in the following form:

Date:

__________________________,

as Authenticating Agent, certifies that this is one of the Notes described

in the within-named Indenture.

By: ____________________

Authorized Signatory

100

Section 17.11. Execution in Counterparts.

This Indenture may be executed in any number of counterparts, each of which shall be an original, but such counterparts shall together

constitute but one and the same instrument. The exchange of copies of this Indenture and of signature pages by facsimile or PDF

transmission shall constitute effective execution and delivery of this Indenture as to the parties hereto and may be used in lieu of

the original Indenture for all purposes. Signatures of the parties hereto transmitted by facsimile or PDF shall be deemed to be their

original signatures for all purposes. This Indenture shall be valid, binding, and enforceable against a party only when executed and

delivered by an authorized individual on behalf of the party by means of (i) any electronic signature permitted by the federal

Electronic Signatures in Global and National Commerce Act, state enactments of the Uniform Electronic Transactions Act, and/or any other

relevant electronic signatures law, including relevant provisions of the Uniform Commercial Code (collectively, “Signature Law”);

(ii) an original manual signature; or (iii) a faxed, scanned, or photocopied manual signature. Each electronic signature

or faxed, scanned, or photocopied manual signature shall for all purposes have the same validity, legal effect, and admissibility in

evidence as an original manual signature. Each party hereto shall be entitled to conclusively rely upon, and shall have no liability

with respect to, any faxed, scanned, or photocopied manual signature, or other electronic signature, of any party and shall have no duty

to investigate, confirm or otherwise verify the validity or authenticity thereof. For avoidance of doubt, original manual signatures

shall be used for execution or indorsement of writings when required under the Uniform Commercial Code or other Signature Law due to

the character or intended character of the writings. All notices, approvals, consents, requests and any communications hereunder must

be in writing; provided that any such communication sent to Trustee hereunder must be in the form of a document that is signed manually

or by way of a digital signature provided by DocuSign or other electronic signature provider that the Company plans to use (or such other

digital signature provider as specified in writing to Trustee by the authorized representative), in English. The Company agrees to assume

all risks arising out of the use of digital signatures and electronic methods to submit communications to Trustee, including without

limitation the risk of Trustee acting on unauthorized instructions, and the risk of interception and misuse by third parties.

Section 17.12. Severability. In the

event any provision of this Indenture or in the Notes shall be invalid, illegal or unenforceable, then (to the extent permitted by law)

the validity, legality or enforceability of the remaining provisions shall not in any way be affected or impaired.

Section 17.13. Waiver of Jury Trial.

EACH OF THE COMPANY AND THE TRUSTEE HEREBY IRREVOCABLY WAIVES, TO THE FULLEST EXTENT PERMITTED BY APPLICABLE LAW, ANY AND ALL RIGHT TO

TRIAL BY JURY IN ANY LEGAL PROCEEDING ARISING OUT OF OR RELATING TO THIS INDENTURE, THE NOTES OR THE TRANSACTIONS CONTEMPLATED HEREBY.

Section 17.14. Force Majeure. In

no event shall the Trustee be responsible or liable for any failure or delay in the performance of its obligations hereunder arising

out of or caused by, directly or indirectly, forces beyond its control, including, without limitation, strikes, work stoppages, accidents,

acts of war or terrorism, civil or military disturbances, nuclear or natural catastrophes or acts of God, labor dispute, disease, epidemic

or pandemic, quarantine, national emergency and interruptions, loss or malfunctions of utilities, communications or computer (software

and hardware) services, communications system failure, malware or ransomware or unavailability of the Federal Reserve Bank wire or telex

system or other wire or other funds transfer systems, or unavailability of any securities clearing system; it being understood that the

Trustee shall use reasonable efforts that are consistent with accepted practices in the banking industry to resume performance as soon

as practicable under the circumstances.

101

Section 17.15. Calculations. The

Company shall be responsible for making all calculations called for under this Indenture and the Notes and the Trustee, the Paying Agent,

the Conversion Agent, Bid Solicitation Agent (if the Trustee) and the Note Registrar shall have no liability or responsibility for any

calculations or any information in connection with such calculations. These calculations include, but are not limited to, determinations

of the Redemption Price, Stock Price, the Trading Price of the Notes (for purposes of determining whether the Notes are convertible as

described herein), the Last Reported Sale Prices of the Common Stock, the Daily VWAPs, the Daily Conversion Values, the Daily Settlement

Amounts, the amount of conversion consideration deliverable in respect of any conversions, accrued Special Interest, if any, payable

on the Notes, any Special Interest that may accrue on the Notes and the Conversion Rate and Conversion Price of the Notes (or any adjustments

to such Conversion Rate or Conversion Price). The Company shall make all these calculations in good faith and, absent manifest error,

the Company’s calculations shall be final and binding on Holders of Notes. The Company shall provide a schedule of its calculations

to each of the Trustee, the Paying Agent and the Conversion Agent, and each of the Trustee, the Paying Agent and Conversion Agent is

entitled to rely conclusively upon the accuracy of the Company’s calculations without independent verification. The Company will

forward or cause the Trustee to forward its calculations to any Holder of Notes upon the written request of that Holder.

Section 17.16. USA PATRIOT Act. The

parties hereto acknowledge that in accordance with Section 326 of the USA PATRIOT Act, the Trustee, like all financial institutions

and in order to help fight the funding of terrorism and money laundering, is required to obtain, verify, and record information that

identifies each person or legal entity that establishes a relationship or opens an account with the Trustee. The parties to this Indenture

agree that they will provide the Trustee with such information as it may request in order for the Trustee to satisfy the requirements

of the USA PATRIOT Act.

[Remainder of page intentionally left

blank]

102

IN WITNESS WHEREOF, the parties hereto have caused

this Indenture to be duly executed as of the date first written above.

PTC THERAPEUTICS, INC.

By:

/s/ Mark E. Boulding

Name:

Mark E. Boulding

Title:

Executive Vice President, Chief Legal Officer

[Signature Page to Indenture]

U.S. BANK TRUST COMPANY,

NATIONAL ASSOCIATION, as Trustee

By:

/s/

Wally Jones

Name:

Wally Jones

Title:

Vice President

[Signature Page to Indenture]

EXHIBIT A

[FORM OF FACE OF NOTE]

[INCLUDE FOLLOWING LEGEND IF A GLOBAL NOTE]

[UNLESS THIS CERTIFICATE

IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION (“DTC”), TO THE COMPANY

OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE, OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE NAME OF CEDE &

CO. OR IN SUCH OTHER NAME AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC (AND ANY PAYMENT HEREUNDER IS MADE TO CEDE &

CO. OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC), ANY TRANSFER, PLEDGE, OR OTHER USE HEREOF FOR VALUE

OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.]

[INCLUDE FOLLOWING LEGEND IF A RESTRICTED SECURITY]

[THIS SECURITY AND THE COMMON

STOCK, IF ANY, ISSUABLE UPON CONVERSION OF THIS SECURITY HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED

(THE “SECURITIES ACT”) AND MAY NOT BE OFFERED, SOLD, PLEDGED OR OTHERWISE TRANSFERRED EXCEPT IN ACCORDANCE WITH THE

FOLLOWING SENTENCE. BY ITS ACQUISITION HEREOF OR OF A BENEFICIAL INTEREST HEREIN, THE ACQUIRER:

(1) REPRESENTS

THAT IT AND ANY ACCOUNT FOR WHICH IT IS ACTING IS A “QUALIFIED INSTITUTIONAL BUYER” (WITHIN THE MEANING OF RULE 144A UNDER

THE SECURITIES ACT) AND THAT IT EXERCISES SOLE INVESTMENT DISCRETION WITH RESPECT TO EACH SUCH ACCOUNT, AND

(2) AGREES

FOR THE BENEFIT OF PTC THERAPEUTICS, INC. (THE “COMPANY”) THAT IT WILL NOT OFFER, SELL, PLEDGE OR OTHERWISE TRANSFER

THIS SECURITY OR ANY BENEFICIAL INTEREST HEREIN PRIOR TO THE DATE THAT IS THE LATER OF (X) ONE YEAR AFTER THE LAST DATE OF ORIGINAL

ISSUANCE HEREOF OR SUCH SHORTER PERIOD OF TIME AS PERMITTED BY RULE 144 UNDER THE SECURITIES ACT OR ANY SUCCESSOR PROVISION THERETO AND

(Y) SUCH LATER DATE, IF ANY, AS MAY BE REQUIRED BY APPLICABLE LAW, EXCEPT:

(A) TO THE

COMPANY OR ANY SUBSIDIARY THEREOF, OR

(B) PURSUANT

TO A REGISTRATION STATEMENT THAT HAS BECOME EFFECTIVE UNDER THE SECURITIES ACT, OR

REASONABLY BELIEVED TO BE A QUALIFIED INSTITUTIONAL BUYER IN COMPLIANCE WITH RULE 144A UNDER THE SECURITIES ACT, OR

A-1

(D) PURSUANT

TO AN EXEMPTION FROM REGISTRATION PROVIDED BY RULE 144 UNDER THE SECURITIES ACT OR ANY OTHER AVAILABLE EXEMPTION FROM THE REGISTRATION

REQUIREMENTS OF THE SECURITIES ACT.

PRIOR TO THE REGISTRATION

OF ANY TRANSFER IN ACCORDANCE WITH CLAUSE (2)(D) ABOVE, THE COMPANY AND THE TRUSTEE RESERVE THE RIGHT TO REQUIRE THE DELIVERY OF

SUCH LEGAL OPINIONS, CERTIFICATIONS OR OTHER EVIDENCE AS MAY REASONABLY BE REQUIRED IN ORDER TO DETERMINE THAT THE PROPOSED TRANSFER

IS BEING MADE IN COMPLIANCE WITH THE SECURITIES ACT AND APPLICABLE STATE SECURITIES LAWS. NO REPRESENTATION IS MADE AS TO THE AVAILABILITY

OF ANY EXEMPTION FROM THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT.]1

NO AFFILIATE (AS DEFINED

IN RULE 144 UNDER THE SECURITIES ACT) OF PTC THERAPEUTICS, INC. OR PERSON THAT HAS BEEN AN AFFILIATE (AS DEFINED IN RULE 144 UNDER

THE SECURITIES ACT) OF PTC THERAPEUTICS, INC. DURING THE IMMEDIATELY PRECEDING THREE MONTHS MAY PURCHASE, OTHERWISE ACQUIRE

OR HOLD THIS SECURITY OR A BENEFICIAL INTEREST HEREIN.

1 This Restricted Security legend shall be deemed removed

from the face of this Security without further action of the Company, the Trustee, or the holders of this Security at such time as the

Company notifies the Trustee that such legend is removed pursuant to and subject to Section 2.05(c) of the Indenture.

A-2

PTC THERAPEUTICS, INC.

0% Convertible Senior Note due 2031

No. [_____]

[Initially]2

$[_________]

CUSIP No. [_____]3

PTC Therapeutics, Inc., a corporation duly

organized and validly existing under the laws of the State of Delaware (the “Company,” which term includes any successor

corporation or other entity under the Indenture referred to on the reverse hereof), for value received hereby promises to pay to [CEDE &

CO.]4 [_______]5, or registered assigns, the principal sum [as set forth in the “Schedule of Exchanges of

Notes” attached hereto]6 [of $[_______]]7, which amount, taken together with the principal amounts of all

other outstanding Notes, shall not, unless permitted by the Indenture, exceed $550,000,000 in aggregate at any time, in accordance with

the rules and procedures of the Depositary, on June 15, 2031, and interest, if any, thereon as set forth below.

This Note shall not bear regular interest, and

the principal amount shall not accrete. Any accrued Special Interest on this Note shall be computed on the basis of a 360-day year composed

of twelve 30-day months and, for partial months, on the basis of the number of days actually elapsed in a 30-day month. Any Special Interest

is payable semi-annually in arrears on each June 15 and December 15, commencing on December 15, 2026 (if any Special

Interest is then payable), to Holders of record at the close of business on the preceding June 1 and December 1 (whether

or not such day is a Business Day), respectively. Any Special Interest will be payable as set forth in Section 4.06(d), Section 4.06(e) and

Section 6.03 of the within-mentioned Indenture, and any reference to interest or Special Interest on, or in respect of, any Note

therein shall be deemed to refer solely to Special Interest (including any Deferred Special Interest and, if applicable, any interest

thereon) if, in such context, Special Interest (including any Deferred Special Interest and, if applicable, any interest thereon) is,

was or would be payable pursuant to any of such Section 4.06(d), Section 4.06(e) or Section 6.03, and/or to any

interest on any Defaulted Amounts payable as set forth in Section 2.03(c) in the within-mentioned Indenture. Unless the context

otherwise requires, any express mention of Special Interest, Deferred Special Interest and/or interest thereon in any provision of this

Note shall not be construed as excluding Special Interest, Deferred Special Interest and/or interest thereon in such provision where

such express mention is not made.

Include if a global note.

At such time as the Company notifies the Trustee that the Restricted Security legend is removed pursuant to Section 2.05(c) of the Indenture,

the CUSIP number for this Security shall be deemed to be CUSIP No. [_____].

Include if a global note.

Include if a physical note.

Include if a global note.

7 Include if a physical note.

A-3

Any Defaulted Amounts shall not accrue interest

unless Special Interest was payable on the required payment date, in which case such Defaulted Amounts shall accrue interest per annum

at the then-applicable Special Interest rate borne by the Notes, subject to the enforceability thereof under applicable law, from, and

including, the relevant payment date to, but excluding, the date on which such Defaulted Amounts shall have been paid by the Company,

at its election, in accordance with Section 2.03(c) of the Indenture.

The Company shall pay the principal of and Special

Interest, if any, on this Note, if and so long as such Note is a Global Note, in immediately available funds to the Depositary or its

nominee, as the case may be, as the registered Holder of such Note. As provided in and subject to the provisions of the Indenture, the

Company shall pay the principal of any Notes (other than Notes that are Global Notes) at the office or agency designated by the Company

for that purpose. The Company has initially designated the Trustee as its Paying Agent and Note Registrar in respect of the Notes and

its Corporate Trust Office located in the United States of America, as a place where Notes may be presented for payment or for registration

of transfer and exchange.

Reference is made to the further provisions of

this Note set forth on the reverse hereof, including, without limitation, provisions giving the Holder of this Note the right to convert

this Note into cash, shares of Common Stock or a combination of cash and shares of Common Stock, as applicable, on the terms and subject

to the limitations set forth in the Indenture. Such further provisions shall for all purposes have the same effect as though fully set

forth at this place.

This Note, and any claim, controversy or dispute

arising under or related to this Note, shall be construed in accordance with and governed by the laws of the State of New York.

In the case of any conflict between this Note

and the Indenture, the provisions of the Indenture shall control and govern.

This Note shall not be valid or become obligatory

for any purpose until the certificate of authentication hereon shall have been signed manually by the Trustee or a duly authorized authenticating

agent under the Indenture.

[Remainder of page intentionally left

blank]

A-4

IN WITNESS WHEREOF, the Company has caused this

Note to be duly executed.

PTC THERAPEUTICS, INC.

By:

Name:

Title:

A-5

Dated:

TRUSTEE’S CERTIFICATE OF AUTHENTICATION

U.S. BANK TRUST COMPANY, NATIONAL ASSOCIATION, as Trustee, certifies

that this is one of the Notes described

in the within-named Indenture.

By:

Authorized Signatory

A-6

[FORM OF REVERSE OF NOTE]

PTC THERAPEUTICS, INC.

0% Convertible Senior Note due 2031

This Note is one of a duly authorized issue of

Notes of the Company, designated as its 0% Convertible Senior Notes due 2031 (the “Notes”), limited to the aggregate

principal amount of $550,000,000 all issued or to be issued under and pursuant to an Indenture dated as of June 18, 2026 (the “Indenture”),

between the Company and U.S. Bank Trust Company, National Association (the “Trustee”), to which Indenture and all

indentures supplemental thereto reference is hereby made for a description of the rights, limitations of rights, obligations, duties

and immunities thereunder of the Trustee, the Company and the Holders of the Notes. Additional Notes may be issued in an unlimited aggregate

principal amount, subject to certain conditions specified in the Indenture. Capitalized terms used in this Note and not defined in this

Note shall have the respective meanings set forth in the Indenture.

In case certain Events of Default shall have occurred

and be continuing, the principal of, and any Special Interest on, all Notes may be declared, by either the Trustee or Holders of at least

25% in aggregate principal amount of Notes then outstanding, and upon said declaration shall become, due and payable, in the manner,

with the effect and subject to the conditions and certain exceptions set forth in the Indenture.

Subject to the terms and conditions of the Indenture,

the Company will make all payments and deliveries in respect of the Fundamental Change Repurchase Price on the Fundamental Change Repurchase

Date, the Redemption Price on any Redemption Date and the principal amount on the Maturity Date, as the case may be, to the Holder who

surrenders a Note to a Paying Agent to collect such payments in respect of the Note. The Company will pay cash amounts in money of the

United States that at the time of payment is legal tender for payment of public and private debts.

The Indenture contains provisions permitting the

Company and the Trustee in certain circumstances, without the consent of the Holders of the Notes, and in certain other circumstances,

with the consent of the Holders of not less than a majority in aggregate principal amount of the Notes at the time outstanding, evidenced

as in the Indenture provided, to execute supplemental indentures modifying the terms of the Indenture and the Notes as described therein.

It is also provided in the Indenture that, subject to certain exceptions, the Holders of a majority in aggregate principal amount of

the Notes at the time outstanding may on behalf of the Holders of all of the Notes waive any past Default or Event of Default under the

Indenture and its consequences.

Each Holder shall have the right to receive payment

or delivery, as the case may be, of (x) the principal (including the Redemption Price and the Fundamental Change Repurchase Price,

if applicable) of, (y) accrued and unpaid Special Interest, if any, on, and (z) the consideration due upon conversion of,

this Note at the place, at the respective times, at the rate and in the lawful money or shares of Common Stock, as the case may be, herein

prescribed.

A-7

The Notes are issuable in registered form without

coupons in denominations of $1,000 principal amount and integral multiples thereof. At the office or agency of the Company referred to

on the face hereof, and in the manner and subject to the limitations provided in the Indenture, Notes may be exchanged for a like aggregate

principal amount of Notes of other authorized denominations, without payment of any service charge but, if required by the Company or

Trustee, with payment of a sum sufficient to cover any transfer or similar tax that may be imposed in connection therewith as a result

of the name of the Holder of the new Notes issued upon such exchange of Notes being different from the name of the Holder of the old

Notes surrendered for such exchange.

The Notes shall be redeemable at the Company’s

option on or after June 20, 2029 in accordance with the terms and subject to the conditions specified in the Indenture. No sinking

fund is provided for the Notes.

Upon the occurrence of a Fundamental Change, the

Holder has the right, at such Holder’s option, to require the Company to repurchase for cash all of such Holder’s Notes or

any portion thereof (in principal amounts of $1,000 or integral multiples thereof) on the Fundamental Change Repurchase Date at a price

equal to the Fundamental Change Repurchase Price.

Subject to the provisions of the Indenture, the

Holder hereof has the right, at its option, during certain periods and upon the occurrence of certain conditions specified in the Indenture,

prior to the close of business on the second Scheduled Trading Day immediately preceding the Maturity Date, to convert any Notes or portion

thereof that is $1,000 or an integral multiple thereof, into cash, shares of Common Stock or a combination of cash and shares of Common

Stock, as applicable, at the Conversion Rate specified in the Indenture, as adjusted from time to time as provided in the Indenture.

A-8

ABBREVIATIONS

The following abbreviations, when used in the

inscription of the face of this Note, shall be construed as though they were written out in full according to applicable laws or regulations:

TEN COM = as tenants in common

UNIF GIFT MIN ACT = Uniform Gifts to Minors Act

CUST = Custodian

TEN ENT = as tenants by the entireties

JT TEN = joint tenants with right of survivorship and not as tenants

in common

Additional abbreviations may also be used though

not in the above list.

A-9

SCHEDULE A8

SCHEDULE OF EXCHANGES OF NOTES

PTC THERAPEUTICS, INC.

0% Convertible Senior Notes due 2031

The initial principal amount of this Global Note

is [_______] DOLLARS ($[_________]). The following increases or decreases in this Global Note have been made:

Date

of exchange

Amount

decrease in

principal amount

of this Global Note

Amount

increase in

principal amount

of this Global Note

Principal

amount

of this Global Note

following such

decrease or

increase

Signature

authorized

signatory of

Trustee or

Custodian

8 Include if a global note.

A-10

ATTACHMENT 1

[FORM OF NOTICE OF CONVERSION]

To:

U.S. Bank Trust Company, National Association

c/o 111 Fillmore Ave E.

St. Paul, MN 55107

Attn: CTS Conversions

Ctso.conversions@usbank.com

The undersigned registered owner of this Note

hereby exercises the option to convert this Note, or the portion hereof (that is $1,000 principal amount or an integral multiple thereof)

below designated, into cash, shares of Common Stock or a combination of cash and shares of Common Stock, as applicable, in accordance

with the terms of the Indenture referred to in this Note, and directs that any cash payable and any shares of Common Stock issuable and

deliverable upon such conversion, together with any cash for any fractional share, and any Notes representing any unconverted principal

amount hereof, be issued and delivered to the registered Holder hereof unless a different name has been indicated below. If any shares

of Common Stock or any portion of this Note not converted are to be issued in the name of a Person other than the undersigned, the undersigned

will pay all documentary, stamp or similar issue or transfer taxes, if any in accordance with Section 14.02(d) and Section 14.02(e) of

the Indenture. Any amount required to be paid to the undersigned on account of any interest accompanies this Note. Capitalized terms

used herein but not defined shall have the meanings ascribed to such terms in the Indenture.

Dated:     _____________________              ________________________________

________________________________

Signature(s)

___________________________

Signature Guarantee

Signature(s) must be guaranteed

by an eligible Guarantor Institution

(banks, stock brokers, savings and

loan associations and credit unions)

with membership in an approved

signature guarantee medallion program

pursuant to Securities and Exchange

Commission Rule 17Ad-15 if shares

of Common Stock are to be issued, or

Notes are to be delivered, other than

to and in the name of the registered holder.

Fill in for registration of shares if

to be issued, and Notes if to

be delivered, other than to and in the

name of the registered holder:

_________________________

(Name)

_________________________

(Street Address)

_________________________

(City, State and Zip Code)

Please print name and address

Principal amount to be converted (if less than all):

$______,000

NOTICE: The above signature(s) of the Holder(s) hereof

must correspond with the name as written upon the face of the Note in every particular without alteration or enlargement or any change

whatsoever.

_________________________

Social Security or Other Taxpayer

Identification Number

ATTACHMENT 2

[FORM OF FUNDAMENTAL CHANGE REPURCHASE NOTICE]

To:

U.S. Bank Trust Company, National Association

c/o 111 Fillmore Ave E.

St. Paul, MN 55107

Attn: CTS Conversions

Ctso.conversions@usbank.com

The undersigned registered owner of this Note

hereby acknowledges receipt of a notice from PTC Therapeutics, Inc. (the “Company”) as to the occurrence of

a Fundamental Change with respect to the Company and specifying the Fundamental Change Repurchase Date and requests and instructs the

Company to pay to the registered holder hereof in accordance with Section 15.02 of the Indenture referred to in this Note (1) the

entire principal amount of this Note, or the portion thereof (that is $1,000 principal amount or an integral multiple thereof) below

designated, and (2) if such Fundamental Change Repurchase Date does not fall during the period after a Special Interest Record

Date and on or prior to the corresponding Special Interest Payment Date, accrued and unpaid Special Interest, if any, thereon to, but

excluding, such Fundamental Change Repurchase Date. Capitalized terms used herein but not defined shall have the meanings ascribed to

such terms in the Indenture.

In the case of Physical Notes, the certificate

numbers of the Notes to be repurchased are as set forth below:

Dated:      _____________________

________________________________

Signature(s)

_________________________

Social Security or Other Taxpayer

Identification Number

Principal amount to be repaid (if less than all):

$______,000

NOTICE: The above signature(s) of the Holder(s) hereof

must correspond with the name as written upon the face of the Note in every particular without alteration or enlargement or any change

whatsoever.

ATTACHMENT 3

[FORM OF ASSIGNMENT AND TRANSFER]

To:

U.S. Bank Trust Company, National Association

c/o 111 Fillmore Ave E.

St. Paul, MN 55107

Attn: CTS Conversions

Ctso.conversions@usbank.com

For value received ____________________________ hereby sell(s), assign(s) and

transfer(s) unto _________________ (Please insert social security or Taxpayer Identification Number of assignee) the within Note,

and hereby irrevocably constitutes and appoints _____________________ attorney to transfer the said Note on the books of the Company,

with full power of substitution in the premises.

In connection with any transfer of the within Note occurring prior

to the Resale Restriction Termination Date, as defined in the Indenture governing such Note, the undersigned confirms that such Note

is being transferred:

¨        To

PTC Therapeutics, Inc. or a subsidiary thereof; or

¨        Pursuant

to a registration statement that has become effective under the Securities Act of 1933, as amended; or

¨        Pursuant

to and in compliance with Rule 144A under the Securities Act of 1933, as amended; or

¨        Pursuant

to and in compliance with Rule 144 under the Securities Act of 1933, as amended, or any other available exemption from the registration

requirements of the Securities Act of 1933, as amended.

Dated: ________________________

_____________________________________

Signature(s)

_____________________________________

Signature Guarantee

Signature(s) must be guaranteed by an

eligible Guarantor Institution (banks, stock

brokers, savings and loan associations and

credit unions) with membership in an approved

signature guarantee medallion program pursuant

to Securities and Exchange Commission Rule 17Ad-15 if Notes are to be delivered, other

than to and in the name of the registered holder.

NOTICE: The signature on the assignment must correspond with the name

as written upon the face of the Note in every particular without alteration or enlargement or any change whatsoever.

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