Form 8-K

8-K — ADTRAN Holdings, Inc.

Accession: 0001193125-26-145496

Filed: 2026-04-07

Period: 2026-04-01

CIK: 0000926282

SIC: 3661 (TELEPHONE & TELEGRAPH APPARATUS)

Item: Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers: Compensatory Arrangements of Certain Officers

Item: Financial Statements and Exhibits

Documents

8-K — adtn-20260401.htm (Primary)

EX-10.1 (adtn-ex10_1.htm)

EX-10.2 (adtn-ex10_2.htm)

EX-10.3 (adtn-ex10_3.htm)

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8-K

8-K (Primary)

Filename: adtn-20260401.htm · Sequence: 1

8-K

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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): April 01, 2026

ADTRAN Holdings, Inc.

(Exact name of Registrant as Specified in Its Charter)

Delaware

001-41446

87-2164282

(State or Other Jurisdiction

of Incorporation)

(Commission File Number)

(IRS Employer

Identification No.)

901 Explorer Boulevard

Huntsville, Alabama

35806-2807

(Address of Principal Executive Offices)

(Zip Code)

Registrant’s Telephone Number, Including Area Code: (256) 963-8000

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:

☐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, Par Value $0.01 per share

ADTN

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 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

Amendment to Thomas Stanton’s Employment Agreement

On April 6, 2026, ADTRAN Holdings, Inc. (the “Company”) entered into a second amendment (the “Amendment”) to its employment agreement, dated July 13, 2022 (as previously amended, the “Employment Agreement”), with Thomas R. Stanton, the Company’s President, Chief Executive Officer and Chairman (the “CEO”). The Amendment was approved by the Board of Directors of the Company (the “Board”) upon the recommendation of the Compensation Committee of the Board (the “Compensation Committee”). The Amendment eliminates the concept of an annual PSU award tied to the performance objective of the Company’s relative total shareholder return. Furthermore, the Amendment adjusts the performance objective of the long-term financial plan PSU award. While the performance objective for this type of award continues to be based upon the Company’s Adjusted EBIT (or such other performance criteria as shall be mutually agreed upon by the CEO and the Compensation Committee) over the applicable performance period, it will also be subject to adjustment based on the Company’s relative total shareholder return over such performance period. Finally, the Amendment adjusts the anticipated value of RSUs and the anticipated target number of long-term financial plan PSUs that the CEO is eligible to receive during the term of the Employment Agreement.

The foregoing description of the Amendment is not complete and is qualified in its entirety by the text of the Amendment, which is attached hereto as Exhibit 10.1 and is incorporated herein by reference.

Long-Term Financial Plan PSU Awards for Certain Named Executive Officers

On April 1, 2026, the Compensation Committee approved grants of long-term financial plan PSU awards to the CEO, Mr. James D. Wilson (Chief Revenue Officer), and Mr. Timothy Santo (Senior Vice President of Finance and Chief Financial Officer) under the Company’s 2024 Employee Stock Incentive Plan. The performance objective of these long-term financial plan PSU awards is based upon the Company’s Adjusted EBIT over the performance period of January 1, 2026 through December 31, 2028, subject to adjustment based on the Company’s relative total shareholder return over such performance period. Specifically, the Compensation Committee approved the grant of a target number of 170,723 shares, 24,908 shares, and 28,252 shares, respectively, to the CEO, Mr. Wilson and Mr. Santo under the long-term financial plan PSU awards. The Company intends to grant later in 2026 a similar award of long-term financial plan PSU awards to Mr. Christoph Glingener (Chief Technology Officer) upon the approval of both the supervisory board and the shareholders of the Company’s majority-owned subsidiary, Adtran Networks SE. The Compensation Committee does not intend to grant annual PSU awards tied to the performance objective of the Company’s relative total shareholder return (referred to as market-based PSUs in the Company’s definitive proxy statement filed with the Securities and Exchange Commission on March 27, 2026) to any of the named executive officers going forward.

The foregoing description of the awards is not complete and is qualified in its entirety by the text of the forms of 2026 3-Year Performance Shares Agreement and 2026 CEO 3-Year Performance Shares Agreement, which are attached hereto as Exhibits 10.2 and 10.3 and are incorporated herein by reference.

Item 9.01 Financial Statements and Exhibits.

Exhibit Number

Description

10.1

Second Amendment to the CEO Employment Agreement, dated April 6, 2026

10.2†

Form of 2026 3-Year Performance Shares Agreement Under the ADTRAN Holdings, Inc. 2024 Employee Stock Incentive Plan

10.3†

Form of 2026 CEO 3-Year Performance Shares Agreement Under the ADTRAN Holdings, Inc. 2024 Employee Stock Incentive Plan

104

Cover Page Interactive Data File – the cover page iXBRL tags are embedded within the Inline XBRL document

† Certain identified information has been excluded from these exhibits because it is not material and is the type of information that the Company customarily and actually treats as private and confidential. Redacted information is indicated by [***].

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.

ADTRAN Holdings, Inc.

Date:

April 7, 2026

By:

/s/ Timothy Santo

Timothy Santo

Senior Vice President of Finance and Chief Financial Officer

EX-10.1

Filename: adtn-ex10_1.htm · Sequence: 2

EX-10.1

Exhibit 10.1

SECOND AMENDMENT TO EMPLOYMENT AGREEMENT

This SECOND AMENDMENT TO EMPLOYMENT AGREEMENT (this “Amendment”)

is entered into effective as of April 6, 2026, by and between Thomas R. Stanton, an individual resident of the State of Alabama (the “Executive”), and ADTRAN Holdings, Inc., a Delaware corporation (the “Company”).

WHEREAS, the Executive, the Company, and ADTRAN, Inc., a Delaware corporation and a wholly-owned subsidiary of the Company, entered into and are parties to that certain Employment Agreement dated July 13, 2022, as amended by the First Amendment to the Employment Agreement dated March 29, 2023 (the “Employment Agreement”); and

WHEREAS, Section 16(e) of the Employment Agreement provides that the Employment Agreement may not be amended unless the Company and the Executive consent in writing to such amendment; and

WHEREAS, the Company and the Executive desire to formally amend the Employment Agreement as hereinafter provided, effective as of the date first written above.

NOW, THEREFORE, in consideration of the mutual covenants and agreements herein contained and other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the parties hereto hereby agree as follows:

Capitalized Terms. Capitalized terms used but not defined in this Amendment shall have the meanings ascribed to such terms in the Employment Agreement.

Amendments.

(a)

Section 4(c)(ii) of the Employment Agreement is hereby deleted in its entirety and replaced with the following:

“(ii) with respect to fiscal year 2026 and each fiscal year thereafter during the Employment Period, the Executive shall be eligible to receive from the Company time-based RSUs with an anticipated value at the date of grant of 211% of Base Salary, vesting ratably over four years following the date of grant and subject to such other terms as shall be provided for in the award agreement evidencing such RSU award (an “Annual RSU Award”); and

(b)

Section 4(c)(iii) of the Employment Agreement is hereby deleted in its entirety and replaced with the following:

“(iii) with respect to fiscal year 2026 and each third fiscal year thereafter during the Employment Period (each such year, a “Triennial Year”), the Executive shall be eligible to receive from the Company a PSU award (a “Long-Term Financial Plan PSU Award”) with an anticipated target number of shares equal to the amount calculated by dividing 633% of Base Salary by the closing price of the Company’s common stock on the date of grant in such Triennial Year (such target number of shares, the “Target PSU Amount”), with any such Long-Term Financial Plan PSU Award to be subdivided into three equal tranches, with the Executive eligible to receive one-third of the Long-Term Financial Plan PSU Award in the Triennial Year, one-third of the Long-Term Financial Plan PSU Award in the fiscal year following the Triennial Year and the remaining one-third of the Long-Term Financial Plan PSU Award in the second fiscal year following the Triennial Year (with the Target PSU Amount for such award to be calculated on the date of grant of the first tranche of such award in the applicable Triennial Year). The performance objective for any Long-Term Financial Plan PSU Award shall be based upon the Company’s Adjusted EBIT (or such other performance criteria as shall be mutually agreed upon by the Executive and the Compensation Committee) over a performance period commencing in the applicable Triennial Year and ending at the end of the second fiscal year after the Triennial Year, with cliff vesting following the end of the applicable performance period, subject to adjustment based on relative Total Shareholder Return over the performance period and with such other terms as shall be set forth in one or more award agreements evidencing such PSU awards.”

Reaffirm Other Provisions. Except as provided herein as to the prescribed items above, the Employment Agreement continues in full force and effect without revision. This Amendment constitutes the final, complete, entire, and exclusive agreement between the Executive and the Employer and supersedes all prior agreements and understandings, whether written or oral, between the Executive and the Employer with respect to the subject matter hereof. If there is any conflict between the terms and provisions of this Amendment and the terms and provisions of the Employment Agreement, then the terms and provisions of this Amendment will govern. From and after the execution of this Amendment, any reference to the Employment Agreement will be deemed to be a reference to the Employment Agreement as amended by this Amendment.

Consent in Writing; Incorporation of Certain Terms. This Amendment constitutes an amendment in writing, executed and consented to by the Company and the Executive for purposes of Section 16(e) of the Employment Agreement. The terms and provisions of Section 16 of the Employment Agreement are incorporated herein mutatis mutandis.

Counterparts. This Amendment may be executed in any number of counterparts, in

each case including by facsimile, portable document format (.pdf) or other electronic transmission, each of which when so executed and delivered shall be taken to be an original; but such counterparts shall together constitute one and the same document.

[Signatures on following page.]

IN WITNESS WHEREOF, the parties have executed this Amendment, effective as of the date first above written.

THE COMPANY:

ADTRAN HOLDINGS, INC.

By: /s/ Timothy Santo

Name: Timothy Santo

Title: Chief Financial Officer

EXECUTIVE:

By: /s/ Thomas R. Stanton

Name: Thomas R. Stanton

[Signature Page to Second Amendment to Employment Agreement]

EX-10.2

Filename: adtn-ex10_2.htm · Sequence: 3

EX-10.2

Exhibit 10.2

* CERTAIN IDENTIFIED INFORMATION HAS BEEN EXCLUDED FROM THIS EXHIBIT BECAUSE IT IS NOT MATERIAL AND IS THE TYPE OF INFORMATION THE REGISTRANT CUSTOMARILY AND ACTUALLY TREATS AS PRIVATE AND CONFIDENTIAL. REDACTED INFORMATION IS INDICATED BY [***].

ADTRAN HOLDINGS, INC.

2026 3-YEAR PERFORMANCE SHARES AGREEMENT

This Performance Shares Agreement (this “Agreement”) sets forth the specified terms of ADTRAN Holdings, Inc.’s grant of the target number of Restricted Stock Units (“Performance Shares”) as it set forth in the Morgan Stanley StockPlan Connect (the “Portal”) to the applicable grantee named in the Portal (the “Participant”) pursuant to the ADTRAN Holdings, Inc. 2024 Employee Stock Incentive Plan (the “Plan”) as of the date of grant set forth in the Portal (the “Date of Grant”). All capitalized terms used but not defined herein shall have the meanings ascribed to such terms in the Plan.

Performance Period: The period beginning on January 1, 2026 and ending on December 31, 2028 (the “Performance Period”).

Satisfaction of Vesting Conditions:

General. Each Performance Share shall represent the right to receive one share of Common Stock of the Company, subject to the terms and conditions set forth in this Agreement and the Plan. The Performance Shares are subject to a substantial risk of forfeiture until cliff vested in accordance with the two conditions specified below or as otherwise noted herein. Except as otherwise provided herein, the Participant shall be entitled to receive shares of Common Stock in respect of the Performance Shares described in this Agreement (“vesting”) only upon the satisfaction of two conditions: a time-based condition and a performance goals condition. The conditions are described in more detail in this Section 2. The Performance Shares shall not vest, and the Participant shall not be entitled to any shares of the Company’s Common Stock, unless both conditions are satisfied.

Performance Goals Condition. The number of shares of the Company’s Common Stock earned by the Participant for the Performance Period, if any, will be determined by the Committee as of the end of the Performance Period based on the level of achievement of the performance goal in accordance with Section 2(c) below, as adjusted pursuant to Section 2(d). Subject to the terms of Sections 2(f) and 2(g) of this Agreement, if the threshold level of the performance goals is not reached for the Performance Period, the Award and the Participant’s right to receive any shares of the Company’s Common Stock with respect to the Performance Period shall automatically expire and be forfeited without payment of any consideration, effective as of the last day of the Performance Period. All determinations of whether and the extent to which the performance goals have been achieved, the number of shares of the Company’s Common Stock earned by the Participant, if any, and all other matters related to this Section 2 shall be made by the Committee in its sole discretion.

Performance Goal Calculation (Adjusted EBIT). Performance Shares shall become vested and earned pursuant to this Agreement beginning at the threshold level (as noted in the table below) of Adjusted EBIT (as defined below) at the conclusion of the Performance Period, but subject to adjustment based on Total Shareholder Return (“TSR”) (as defined below) pursuant to Section 2(d). The Adjusted EBIT target in 2028 of $[***] is required to achieve 100% of the Award. The threshold for any Performance Share Award is Adjusted EBIT of $[***]. If the Adjusted EBIT targets are achieved per the table below at

the end of the Performance Period, then the number of Performance Shares that shall become vested and earned pursuant to this Agreement shall be determined pursuant to the table below, as adjusted based on TSR pursuant to Section 2(d) below. If actual performance of Adjusted EBIT falls between the specified amounts in the table below, percentage achievement will be interpolated linearly between the achievement levels. If the target value of $[***] is achieved at the end of 2026 or 2027, the Award achievement will lock-in for a minimum payment at the 100% of target level, as adjusted based on TSR pursuant to Section 2(d) as of the end of the Performance Period, with the vesting schedule unchanged.

For purposes of this Agreement, “Adjusted EBIT” is synonymous with the Company’s non-GAAP operating income. Using the Company’s audited financial results, it is the calculated earnings before interest and taxes adjusted for restructuring expenses; acquisition-related expenses, amortizations, and adjustments; stock-based compensation expense; amortization of actuarial pension losses, the impact of equity market changes on deferred compensation expenses; non-operating income; and any other non-GAAP exclusions adopted by the Company.

Total Company Adjusted EBIT

% of Target Achieved

Adjusted EBIT

% of Target Award (Subject to the TSR

Adjustment)

75% (Threshold)

$[***]

50%

100% (Target)

$[***]

100%

110%

$[***]

125%

120% (Maximum)

$[***] or greater

150%

Performance Goal Calculation (TSR Adjustment). Following the determination of the achievement of the performance goal pursuant to Section 2(c) above, the Committee will then adjust the number of shares of the Company’s Common Stock earned by the Participant for the Performance Period based upon the Total Company Adjusted EBIT (the “EBIT Shares”) to take into account the Company’s TSR during the Performance Period relative to all companies in the NASDAQ Telecommunications Index (the “relative TSR”). Specifically, the EBIT Shares will be adjusted based on the Company’s relative TSR performance during the Performance Period in accordance with the sliding scale set forth below. If relative TSR performance during the Performance Period falls between the specified amounts in the table below, the target percentage achievement will be interpolated linearly between the achievement levels.

The Company’s TSR Performance relative to the Nasdaq Telecommunications Index (expressed as

a percentile)

Adjustment Percentage to EBIT Shares

30th Percentile or less

Decrease by 20%

55th Percentile

No change (0%)

80th Percentile or greater

Increase by 20%

For example, if, at the end of the Performance Period, the Company has achieved Adjusted EBIT of

receive 120% of the Performance Share Award since the Target Adjusted EBIT was achieved (100% achievement) and the TSR Performance resulted in a 20% increase to the Award. If the Company instead achieved Adjusted EBIT of $[***] and a 30th Percentile TSR Performance, the Participant would receive 80% of the Performance Share Award since the Target Adjusted EBIT was achieved (100% achievement) and the TSR Performance resulted in a 20% decrease to the Award. If the Company achieved Adjusted EBIT of less than $[***] and is at the 55th percentile relative TSR performance, the Participant would receive 0% of the Performance Share Award since the Threshold Adjusted EBIT was not achieved. Finally, if the Company achieved Adjusted EBIT of greater than $[***] and is at the 80th percentile relative TSR performance, the Participant would receive 180% of the Performance Share Award since the Maximum Adjusted EBIT was achieved and the TSR Performance resulted in a 20% increase to the Award.

Time-Based Condition. Except as specifically set forth herein or as approved by the Committee or the Chief Executive Officer (as and to the extent permitted in the Plan), the Performance Shares shall be forfeited in the event the Participant incurs a Separation from Service for any reason prior to the end of the Performance Period.

Accelerated Vesting and Delivery: Notwithstanding the foregoing and including in the event of (1) the Participant’s death or (2) the Participant’s Disability, the Committee or the Chief Executive Officer (as and to the extent permitted in the Plan) have the discretionary power to accelerate the exercisability or vesting of, any Award granted under the Plan, or to permit the continued vesting of any such Award according to its original vesting schedule, notwithstanding the Participant’s Separation from Service for any reason.

Change of Control: In the event of a Change of Control of the Company and the Participant’s involuntary Separation from Service without Cause within twenty-four (24) months following consummation of the Change of Control, any incomplete Performance Period shall end on the date of such Separation from Service, and the portion of the granted Performance Shares that shall be deemed earned and vested by the Participant shall be based upon the higher of: (i) the actual number of Performance Shares earned for the Performance Period through the date of the Participant’s Separation from Service (as calculated pursuant to Sections 2(c) and 2(d) herein) or (ii) the target number of Performance Shares granted pursuant to this Agreement, except that, in each case, the number of Performance Shares that shall be deemed to be earned, if any, will be pro-rated based on the number of days that the Participant was employed by the Company between January 1, 2026 and the date of the Participant’s Separation from Service. One share of the Company’s Common Stock shall be issued to the Participant for every earned Performance Share as soon as administratively practicable following the Separation from Service. The Performance Shares granted herein shall not vest upon a Change of Control in the absence of a Separation from Service without Cause except as may be approved by the Committee.

Settlement of the Performance Shares. One share of the Company’s Common Stock shall be delivered to the Participant for every earned Performance Share following the completion of the Performance Period. Specifically, the Company will issue one share of Common Stock for each earned Performance Share as soon as administratively practicable following the date that the Performance Shares have been determined to have been vested and earned (which shall be as soon as practicable following the release of the Company’s Annual Report on Form 10-K for the last year of the Performance Period) and, in any case no later than 15 days following the filing of the Annual Report on Form 10-K with the Securities and Exchange Commission; provided, however, if any law or regulation requires the Company to take any action (including, but not limited to, the filing of a registration statement under the 1933 Act and causing such registration statement to become effective) with respect to such shares of Common Stock before the delivery thereof, then the date of delivery of the shares shall be extended for the period necessary to take such action, to the maximum extent permitted by Section 409A of the Code.

Dividend Credits: If applicable, the Participant shall receive dividend credits upon the Company’s payment of cash dividends for its Common Stock during the Performance Period as follows:

The Participant shall receive dividend credits on the unvested portion of the original number of Performance Shares awarded on the Date of Grant (“Original Performance Shares”), with the amount of such dividend credits credited to the Participant in the form of additional unvested Performance Shares, as calculated pursuant to the Plan.

The Participant’s Performance Shares attributable to any dividend credits will be vested and earned in accordance with the schedule of the Original Performance Shares (as described above).

Designation of Beneficiary: The Participant hereby designates the following individual as the beneficiary of this Agreement:

Participant Name:

Beneficiary Name:

Address:

Relationship:

To complete this beneficiary designation, this Agreement should be printed out, the information above should then be completed, and the Agreement should then be emailed to Human Resources at humanresources@adtran.com. The Participant may modify this designation of beneficiary only in accordance with the terms and provisions of the Plan. If no beneficiary is designated, then except as may be provided in the Plan, any benefits due hereunder following the death of the Participant will be paid to the Participant’s estate.

Miscellaneous. The Performance Shares are granted pursuant to the Plan. The Participant has received a copy of the Plan’s prospectus, including a copy of the Plan. The Award’s date of grant is deemed to be the date that such Award is approved by the Committee or the Chief Executive Officer, as applicable. The Participant is deemed to have accepted this Award unless he or she expressly elects to reject the Award by notifying Human Resources within 30 days of receiving a notice in the portal that the Award has been granted. Neither this Award nor any terms contained in this Agreement shall (i) confer upon the Participant any express or implied right to be retained in the employment or service of the Company or any affiliate for any period, nor restrict in any way the right of the Company, which right is hereby expressly reserved, to terminate the Participant’s employment or service at any time with or without Cause or (ii) entitle the Participant to receive any future equity awards from the Company. Finally, the Participant will have no rights as a stockholder with respect to any shares of Common Stock underlying the Performance Shares unless and until shares are issued and delivered in accordance with Section 3.

If there are any questions regarding the Performance Shares, please refer to the Plan or contact Human Resources at humanresources@adtran.com.

ADTRAN HOLDINGS, INC.

Thomas R. Stanton Chief Executive Officer

PARTICIPANT

Name:

EX-10.3

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EX-10.3

Exhibit 10.3

ADTRAN HOLDINGS, INC.

2026 T. STANTON 3-YEAR PERFORMANCE SHARES AGREEMENT

This Performance Shares Agreement (this “Agreement”) sets forth the specified terms of ADTRAN Holdings, Inc.’s grant of the target number of Restricted Stock Units (“Performance Shares”) as it set forth in the Morgan Stanley StockPlan Connect (the “Portal”) to the applicable grantee named in the Portal (the “Participant”) pursuant to the ADTRAN Holdings, Inc. 2024 Employee Stock Incentive Plan (the “Plan”) as of the date of grant set forth in the Portal (the “Date of Grant”). Unless otherwise specified, all capitalized terms used but not defined herein shall have the meanings ascribed to such terms in the Plan.

Performance Period: The period beginning on January 1, 2026 and ending on December 31, 2028 (the “Performance Period”).

Satisfaction of Vesting Conditions:

Total Company Adjusted EBIT

% of Target Achieved

Adjusted EBIT

% of Target Award (Subject to the TSR Adjustment)

75% (Threshold)

$[***]

50%

100% (Target)

$[***]

100%

110%

$[***]

125%

120% (Maximum)

$[***] or greater

150%

The Company’s TSR Performance relative to the Nasdaq Telecommunications Index (expressed as

a percentile)

Adjustment Percentage to EBIT Shares

30th Percentile or less

Decrease by 20%

55th Percentile

No change (0%)

80th Percentile or greater

Increase by 20%

For example, if, at the end of the Performance Period, the Company has achieved Adjusted EBIT of

$[***] and is at the 55th percentile relative TSR performance, the Participant would receive 100% of the Performance Share Award since the Target Adjusted EBIT was achieved (100% achievement) and the relative TSR performance resulted in no adjustment to the Award. However, if the Company instead achieved Adjusted EBIT of $[***] and an 85th percentile relative TSR performance, the Participant would receive 120% of the Performance Share Award since the Target Adjusted EBIT was achieved (100% achievement) and the TSR Performance resulted in a 20% increase to the Award. If the Company instead

achieved Adjusted EBIT of $[***] and a 30th Percentile TSR Performance, the Participant would receive 80% of the Performance Share Award since the Target Adjusted EBIT was achieved (100% achievement) and the TSR Performance resulted in a 20% decrease to the Award. If the Company achieved Adjusted EBIT of less than $[***] and is at the 55th percentile relative TSR performance, the Participant would receive 0% of the Performance Share Award since the Threshold Adjusted EBIT was not achieved. Finally, if the Company achieved Adjusted EBIT of greater than $[***] and is at the 80th percentile relative TSR performance, the Participant would receive 180% of the Performance Share Award since the Maximum Adjusted EBIT was achieved and the TSR Performance resulted in a 20% increase to the Award.

Time-Based Condition. Except as specifically set forth herein, as specified by the terms of the Employment Agreement (as defined below), or as otherwise approved by the Committee or the Chief Executive Officer (as and to the extent permitted in the Plan), the Performance Shares shall be forfeited without payment of any consideration in the event the Participant incurs a Separation from Service for any reason prior to the end of the Performance Period.

Separation From Service: The Participant is a party to that certain Employment Agreement, dated July 13, 2022, by and between Thomas R. Stanton, ADTRAN, Inc., and the Company, as amended (the “Employment Agreement”). In the event that the Participant incurs a Separation from Service, the treatment of the Performance Shares shall be governed by the Employment Agreement. In the event that the Participant earns any Performance Shares upon Separation from Service, one share of the Company’s Common Stock shall be issued to the Participant for every earned Performance Share as soon as administratively possible following such Separation from Service.

Change of Control: In the event of a Separation from Service following a Change of Control, the treatment of the Performance Shares shall be governed by the Employment Agreement. One share of the Company’s Common Stock shall be issued to the Participant for every earned Performance Share as soon as administratively practicable following the Separation from Service. The Performance Shares granted herein shall not vest upon a Change of Control in the absence of a Separation from Service except as may be approved by the Committee.

Dividend Credits: If applicable, the Participant shall receive dividend credits upon the Company’s payment of cash dividends for its Common Stock during the Performance Period as follows:

The Participant’s Performance Shares attributable to any dividend credits will be

vested and earned in accordance with the schedule of the Original Performance Shares (as described above).

Designation of Beneficiary: The Participant hereby designates the following individual as the beneficiary of this Agreement:

Participant Name:

Beneficiary Name:

Address:

Relationship:

Miscellaneous. The Performance Shares are granted pursuant to and are subject to the terms of the Plan. The Participant has received a copy of the Plan’s prospectus, including a copy of the Plan. The Award’s Date of Grant is deemed to be the date that such Award is approved by the Committee, which date is reflected in the Portal. The Participant is deemed to have accepted this Award unless he or she expressly elects to reject the Award by notifying Human Resources within 30 days of receiving a notice in the portal that the Award has been granted. In the event of any conflict between the terms of this Agreement and the terms of the Employment Agreement with respect to the impact of a Separation from Service on this Award, the terms of the Employment Agreement shall control. Furthermore, the Employment Agreement shall be considered part of this Agreement (and therefore an Award Agreement) for purposes of the Plan and shall be considered approved by the Committee for purposes of the Plan. Neither this Award nor any terms contained in this Agreement shall (i) confer upon the Participant any express or implied right to be retained in the employment or service of the Company or any affiliate for any period, nor restrict in any way the right of the Company, which right is hereby expressly reserved, to terminate the Participant’s employment or service at any time with or without Cause or (ii) entitle the Participant to receive any future equity awards from the Company. Finally, the Participant will have no rights as a stockholder with respect to any shares of Common Stock underlying the Performance Shares unless and until shares are issued and delivered in accordance with Section 3.

If there are any questions regarding this Agreement or the Performance Shares, please refer to the Plan or contact Human Resources at humanresources@adtran.com.

ADTRAN HOLDINGS, INC.

By: [Name of Officer] Title: [ ]

PARTICIPANT

Name:

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v3.26.1

Document And Entity Information

Apr. 01, 2026

Cover [Abstract]

Document Type

8-K

Amendment Flag

false

Document Period End Date

Apr. 01, 2026

Entity Registrant Name

ADTRAN Holdings, Inc.

Entity Central Index Key

0000926282

Entity Emerging Growth Company

false

Entity File Number

001-41446

Entity Incorporation, State or Country Code

Entity Tax Identification Number

87-2164282

Entity Address, Address Line One

901 Explorer Boulevard

Entity Address, City or Town

Huntsville

Entity Address, State or Province

Entity Address, Postal Zip Code

35806-2807

City Area Code

(256)

Local Phone Number

963-8000

Entity Information, Former Legal or Registered Name

Not Applicable

Written Communications

false

Soliciting Material

false

Pre-commencement Tender Offer

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Pre-commencement Issuer Tender Offer

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Title of 12(b) Security

Common Stock, Par Value $0.01 per share

Trading Symbol

ADTN

Security Exchange Name

NASDAQ

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Boolean flag that is true when the XBRL content amends previously-filed or accepted submission.

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Area code of city

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Cover page.

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For the EDGAR submission types of Form 8-K: the date of the report, the date of the earliest event reported; for the EDGAR submission types of Form N-1A: the filing date; for all other submission types: the end of the reporting or transition period. The format of the date is YYYY-MM-DD.

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The type of document being provided (such as 10-K, 10-Q, 485BPOS, etc). The document type is limited to the same value as the supporting SEC submission type, or the word 'Other'.

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No definition available.

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Address Line 1 such as Attn, Building Name, Street Name

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Name of the City or Town

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Code for the postal or zip code

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Name of the state or province.

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- Definition

A unique 10-digit SEC-issued value to identify entities that have filed disclosures with the SEC. It is commonly abbreviated as CIK.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection b-2

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Indicate if registrant meets the emerging growth company criteria.

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Commission file number. The field allows up to 17 characters. The prefix may contain 1-3 digits, the sequence number may contain 1-8 digits, the optional suffix may contain 1-4 characters, and the fields are separated with a hyphen.

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Two-character EDGAR code representing the state or country of incorporation.

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Former Legal or Registered Name of an entity

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The exact name of the entity filing the report as specified in its charter, which is required by forms filed with the SEC.

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The Tax Identification Number (TIN), also known as an Employer Identification Number (EIN), is a unique 9-digit value assigned by the IRS.

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Local phone number for entity.

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- Definition

Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

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-Section 13e

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Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

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Title of a 12(b) registered security.

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Name of the Exchange on which a security is registered.

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-Name Exchange Act

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-Section 12

-Subsection d1-1

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Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as soliciting material pursuant to Rule 14a-12 under the Exchange Act.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

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-Section 14a

-Subsection 12

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Trading symbol of an instrument as listed on an exchange.

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Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as written communications pursuant to Rule 425 under the Securities Act.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

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-Section 425

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