Form 8-K
8-K — MUSTANG BIO, INC.
Accession: 0001104659-26-116233
Filed: 2026-10-15
Period: 2026-10-13
CIK: 0001680048
SIC: 2834 (PHARMACEUTICAL PREPARATIONS)
Item: Other Events
Documents
8-K — tmb-20261013x8k.htm (Primary)
XML — IDEA: XBRL DOCUMENT (R1.htm)
8-K
8-K (Primary)
Filename: tmb-20261013x8k.htm · Sequence: 1
Mustang Bio, Inc._October 13, 2026
0001680048false00016800482026-10-132026-10-13
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): October 13, 2026
Mustang Bio, Inc.
(Exact Name of Registrant as Specified in Charter)
Delaware
001-38191
47-3828760
(State or Other Jurisdiction
of Incorporation)
(Commission File Number)
(IRS Employer
Identification No.)
95 Sawyer Road, Suite 110
Waltham, Massachusetts 02453
(Address of Principal Executive Offices)
(781) 652-4500
(Registrant’s telephone number, including area code)
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 $0.0001 per share
MBIO
Nasdaq Capital 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). ☐
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 8.01 Other Events
As previously disclosed, on April 15, 2026, Mustang Bio, Inc. (the “Company”) received a notice from the Listing Qualifications Department (the “Staff”) of The Nasdaq Stock Market LLC (“Nasdaq”) notifying the Company that the bid price of the Company’s common stock, par value $0.0001 per share (“Common Stock”), had closed below $1.00 per share for 30 consecutive business days and, as a result, the Company was not in compliance with Nasdaq Listing Rule 5550(a)(2), which sets forth the minimum bid price requirement for continued listing on the Nasdaq Capital Market (the “Bid Price Requirement”). The Staff notice had no immediate effect on the listing of the Company’s Common Stock on Nasdaq.
In accordance with Nasdaq Listing Rule 5810(c)(3)(A), the Company was afforded an initial 180-calendar day grace period, or until October 12, 2026, to regain compliance with the Bid Price Requirement. The Company was unable to demonstrate compliance with the Bid Price Requirement by that date. However, the Company submitted a request for an additional 180-calendar day grace period based upon (i) the Company’s belief that, as of October 12, 2026, it satisfied the continued listing requirement for market value of publicly held shares and all other applicable requirements for initial listing on The Nasdaq Capital Market, except for the Bid Price Requirement, and (ii) the Company’s written notice to Nasdaq of its intention to cure the deficiency during the second grace period by effecting a reverse stock split, if necessary.
On October 13, 2026, the Company received a letter from the Staff granting the Company’s request for an additional 180-calendar day period, or until April 12, 2027, to regain compliance with the Bid Price Requirement. Compliance can be achieved by evidencing a closing bid price of at least $1.00 per share for a minimum of 10 consecutive business days (but generally not more than 20 consecutive business days) during the second 180-calendar day grace period. In the event the Company does not regain compliance by the end of the second grace period, the Staff will provide written notification that the Company’s Common Stock will be delisted. At that time, the Company may appeal the Staff’s determination to the Nasdaq Hearings Panel, although an appeal would not pause any suspension of trading.
The Company intends to closely monitor the closing bid price of its Common Stock and to take all reasonable measures available to regain compliance under the Nasdaq Listing Rules and remain listed on Nasdaq, including effecting a reverse stock split, if necessary. However, there can be no assurance that the Company will ultimately regain compliance with all applicable requirements for continued listing.
SIGNATURES
Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.
Mustang Bio, Inc.
Date: October 15, 2026
By:
/s/ Manuel Litchman, M.D.
Manuel Litchman, M.D.
President, Chief Executive Officer and Interim Chief Financial Officer
XML — IDEA: XBRL DOCUMENT
XML
Filename: R1.htm · Sequence: 6
v3.26.3
Document and Entity Information
Oct. 13, 2026
Document and Entity Information [Abstract]
Document Type
8-K
Amendment Flag
false
Document Period End Date
Oct. 13, 2026
Entity File Number
001-38191
Entity Registrant Name
Mustang Bio, Inc.
Entity Central Index Key
0001680048
Entity Tax Identification Number
47-3828760
Entity Incorporation, State or Country Code
DE
Entity Address, Address Line One
95 Sawyer Road, Suite 110
Entity Address, City or Town
Waltham
Entity Address State Or Province
MA
Entity Address, Postal Zip Code
02453
City Area Code
781
Local Phone Number
652-4500
Written Communications
false
Soliciting Material
false
Pre-commencement Tender Offer
false
Pre-commencement Issuer Tender Offer
false
Title of 12(b) Security
Common Stock, par value $0.0001 per share
Trading Symbol
MBIO
Security Exchange Name
NASDAQ
Entity Emerging Growth Company
false
X
- Definition
Boolean flag that is true when the XBRL content amends previously-filed or accepted submission.
+ References
No definition available.
+ Details
Name:
dei_AmendmentFlag
Namespace Prefix:
dei_
Data Type:
xbrli:booleanItemType
Balance Type:
na
Period Type:
duration
X
- Definition
Area code of city
+ References
No definition available.
+ Details
Name:
dei_CityAreaCode
Namespace Prefix:
dei_
Data Type:
xbrli:normalizedStringItemType
Balance Type:
na
Period Type:
duration
X
- Definition
Cover page.
+ References
No definition available.
+ Details
Name:
dei_CoverAbstract
Namespace Prefix:
dei_
Data Type:
xbrli:stringItemType
Balance Type:
na
Period Type:
duration
X
- Definition
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.
+ References
No definition available.
+ Details
Name:
dei_DocumentPeriodEndDate
Namespace Prefix:
dei_
Data Type:
xbrli:dateItemType
Balance Type:
na
Period Type:
duration
X
- Definition
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'.
+ References
No definition available.
+ Details
Name:
dei_DocumentType
Namespace Prefix:
dei_
Data Type:
dei:submissionTypeItemType
Balance Type:
na
Period Type:
duration
X
- Definition
Address Line 1 such as Attn, Building Name, Street Name
+ References
No definition available.
+ Details
Name:
dei_EntityAddressAddressLine1
Namespace Prefix:
dei_
Data Type:
xbrli:normalizedStringItemType
Balance Type:
na
Period Type:
duration
X
- Definition
Name of the City or Town
+ References
No definition available.
+ Details
Name:
dei_EntityAddressCityOrTown
Namespace Prefix:
dei_
Data Type:
xbrli:normalizedStringItemType
Balance Type:
na
Period Type:
duration
X
- Definition
Code for the postal or zip code
+ References
No definition available.
+ Details
Name:
dei_EntityAddressPostalZipCode
Namespace Prefix:
dei_
Data Type:
xbrli:normalizedStringItemType
Balance Type:
na
Period Type:
duration
X
- Definition
Name of the state or province.
+ References
No definition available.
+ Details
Name:
dei_EntityAddressStateOrProvince
Namespace Prefix:
dei_
Data Type:
dei:stateOrProvinceItemType
Balance Type:
na
Period Type:
duration
X
- Definition
A unique 10-digit SEC-issued value to identify entities that have filed disclosures with the SEC. It is commonly abbreviated as CIK.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Exchange Act
-Number 240
-Section 12
-Subsection b-2
+ Details
Name:
dei_EntityCentralIndexKey
Namespace Prefix:
dei_
Data Type:
dei:centralIndexKeyItemType
Balance Type:
na
Period Type:
duration
X
- Definition
Indicate if registrant meets the emerging growth company criteria.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Exchange Act
-Number 240
-Section 12
-Subsection b-2
+ Details
Name:
dei_EntityEmergingGrowthCompany
Namespace Prefix:
dei_
Data Type:
xbrli:booleanItemType
Balance Type:
na
Period Type:
duration
X
- Definition
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.
+ References
No definition available.
+ Details
Name:
dei_EntityFileNumber
Namespace Prefix:
dei_
Data Type:
dei:fileNumberItemType
Balance Type:
na
Period Type:
duration
X
- Definition
Two-character EDGAR code representing the state or country of incorporation.
+ References
No definition available.
+ Details
Name:
dei_EntityIncorporationStateCountryCode
Namespace Prefix:
dei_
Data Type:
dei:edgarStateCountryItemType
Balance Type:
na
Period Type:
duration
X
- Definition
The exact name of the entity filing the report as specified in its charter, which is required by forms filed with the SEC.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Exchange Act
-Number 240
-Section 12
-Subsection b-2
+ Details
Name:
dei_EntityRegistrantName
Namespace Prefix:
dei_
Data Type:
xbrli:normalizedStringItemType
Balance Type:
na
Period Type:
duration
X
- Definition
The Tax Identification Number (TIN), also known as an Employer Identification Number (EIN), is a unique 9-digit value assigned by the IRS.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Exchange Act
-Number 240
-Section 12
-Subsection b-2
+ Details
Name:
dei_EntityTaxIdentificationNumber
Namespace Prefix:
dei_
Data Type:
dei:employerIdItemType
Balance Type:
na
Period Type:
duration
X
- Definition
Local phone number for entity.
+ References
No definition available.
+ Details
Name:
dei_LocalPhoneNumber
Namespace Prefix:
dei_
Data Type:
xbrli:normalizedStringItemType
Balance Type:
na
Period Type:
duration
X
- 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.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Exchange Act
-Number 240
-Section 13e
-Subsection 4c
+ Details
Name:
dei_PreCommencementIssuerTenderOffer
Namespace Prefix:
dei_
Data Type:
xbrli:booleanItemType
Balance Type:
na
Period Type:
duration
X
- 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 14d-2(b) under the Exchange Act.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Exchange Act
-Number 240
-Section 14d
-Subsection 2b
+ Details
Name:
dei_PreCommencementTenderOffer
Namespace Prefix:
dei_
Data Type:
xbrli:booleanItemType
Balance Type:
na
Period Type:
duration
X
- Definition
Title of a 12(b) registered security.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Exchange Act
-Number 240
-Section 12
-Subsection b
+ Details
Name:
dei_Security12bTitle
Namespace Prefix:
dei_
Data Type:
dei:securityTitleItemType
Balance Type:
na
Period Type:
duration
X
- Definition
Name of the Exchange on which a security is registered.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Exchange Act
-Number 240
-Section 12
-Subsection d1-1
+ Details
Name:
dei_SecurityExchangeName
Namespace Prefix:
dei_
Data Type:
dei:edgarExchangeCodeItemType
Balance Type:
na
Period Type:
duration
X
- Definition
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.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Exchange Act
-Number 240
-Section 14a
-Subsection 12
+ Details
Name:
dei_SolicitingMaterial
Namespace Prefix:
dei_
Data Type:
xbrli:booleanItemType
Balance Type:
na
Period Type:
duration
X
- Definition
Trading symbol of an instrument as listed on an exchange.
+ References
No definition available.
+ Details
Name:
dei_TradingSymbol
Namespace Prefix:
dei_
Data Type:
dei:tradingSymbolItemType
Balance Type:
na
Period Type:
duration
X
- Definition
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.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Securities Act
-Number 230
-Section 425
+ Details
Name:
dei_WrittenCommunications
Namespace Prefix:
dei_
Data Type:
xbrli:booleanItemType
Balance Type:
na
Period Type:
duration