Notice of Delisting of Failure to Satisfy a Continued Listing Rule or Standard; Transfer of Listing. 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”) indicating 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 is not in compliance wi…

Completion of Acquisition or Disposition of Assets As previously disclosed, as of February 10, 2025, Mustang Bio, Inc. (the “Company”) entered into a Bill of Sale and Surrender Agreement (the “Sale/Surrender Agreement”), effective as of January 31, 2025 (the “Effective Date”), with AbbVie Bioresearch Center Inc., a Delaware corporation (“AbbVie”). The Company was the tenant in the leased premises located at 377 Plantation Street, Worcester, Massachusetts (the “Premises”) under a Lease Agreeme…

by reference with respect to the termination of the Lease pursuant to the Amendment. Cautionary Note Regarding Forward-looking Statements This Current Report on Form 8-K contains predictive or “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995. All statements other than statements of current or historical fact contained in this Current Report on Form 8-K, including statements that express the Company’s intentions, plans, objectives, beliefs…

Entry Into a Material Definitive Agreement. Bill of Sale and Surrender Agreement Effective February 10, 2025, Mustang Bio, Inc. (the “Company”) entered into a Bill of Sale and Surrender Agreement (the “Sale/Surrender Agreement”), effective as of January 31, 2025 (the “Effective Date”), with AbbVie Bioresearch Center Inc., a Delaware corporation (“AbbVie”). The Company is the current tenant in the leased premises located at 377 Plantation Street, Worcester, Massachusetts (the “Premises”) under…

Entry Into a Material Definitive Agreement. Securities Purchase Agreement On February 5, 2025, Mustang Bio, Inc. (the “Company”) commenced a best efforts public offering (the “Offering”) of an aggregate of (i) 495,000 shares (the “Shares”) of its common stock, par value $0.0001 per share, (ii) pre-funded warrants (the “Pre-Funded Warrants”) to purchase up to an aggregate of 2,162,807 shares of common stock (the “Pre-Funded Warrant Shares”), (iii) Series C-1 warrants (the “Series C-1 Warrants”…

Other Events. Nasdaq Continued Listing Requirements As previously disclosed, the Company had been notified by the Staff of the Listing Qualifications Department (the “Staff”) of The Nasdaq Stock Market LLC (“Nasdaq”) that it was not in compliance with Nasdaq Listing Rule 5550(b)(1), which requires a company to maintain a minimum of $2.5 million in stockholders’ equity (the “Equity Rule”), nor did it meet the alternatives of market value of listed securities or net income from continuing opera…

Material Modification to Rights of Security Holders On January 15, 2025, Mustang Bio, Inc. (the “Company”) filed a Certificate of Amendment (the “Amendment”) to its Amended and Restated Certificate of Incorporation, as amended, with the Secretary of State of the State of Delaware to effect a 1-for-50 reverse stock split (the “Reverse Stock Split”) of the Company’s shares of common stock, $0.0001 par value. As previously disclosed in the Company’s Definitive Information Statement on Schedule 1…

Notice of Delisting or Failure to Satisfy a Continued Listing Rule or Standard; Transfer of Listing. As previously disclosed, on May 16, 2024, Mustang Bio, Inc. (the “Company”) was notified by the Listing Qualifications Staff (the “Staff”) of The Nasdaq Stock Market LLC (“Nasdaq”) that the bid price for the Company’s common stock had closed below $1.00 per share for 30 consecutive business days and, as a result, the Company no longer satisfied Nasdaq Listing Rule 5550(a)(2) (the “Bid Price Ru…

Interim Chief Financial Officer — James Murphy: James Murphy resigned as the Interim Chief Financial Officer without a named successor.

Unregistered Sales of Equity Securities. The offer and sale of the New Warrants, the Placement Agent Warrants, the New Warrant Shares and the Placement Agent Warrant Shares have not been registered under the Securities Act and were offered pursuant to the exemption from registration provided in Section 4(a)(2) under the Securities Act. The descriptions of the New Warrants and Placement Agent Warrants under

Director — David Jin: David Jin was appointed as a new member of the Board.

Entry into a Material Definitive Agreement. On October 24, 2024, Mustang Bio, Inc. (the “Company”) entered into an inducement offer letter agreement (the “Inducement Letter”) with an institutional investor (the “Investor”) that held certain outstanding Series A-3 warrants to purchase up to an aggregate of 16,877,638 shares of the Company’s common stock, par value $0.0001 per share (“Common Stock”), originally issued to the Investor on May 2, 2024 (the “Existing Warrants”). The Existing Warran…

Notice of Delisting or Failure to Satisfy a Continued Listing Rule or Standard; Transfer of Listing. As previously disclosed, on May 16, 2024, the Staff of the Listing Qualifications Department (the “Staff”) of The Nasdaq Stock Market LLC (“Nasdaq”) granted Mustang Bio, Inc. (the “Company”) an extension through September 9, 2024, to regain compliance with the $2.5 million stockholders’ equity requirement for continued listing on The Nasdaq Capital Market, as set forth in Nasdaq Listing Rule 5…

Completion of Acquisition or Disposition of Assets. The information required by this item is included in

Entry into a Material Definitive Agreement. Background of the uBriGene Transaction As previously reported, o n May 18, 2023, Mustang Bio, Inc. (the “Company”) entered into an Asset Purchase Agreement (the “Original Asset Purchase Agreement”) with uBriGene (Boston) Biosciences, Inc., a Delaware corporation (“uBriGene”), pursuant to which the Company agreed to sell its leasehold interest in its cell processing facility located in Worcester, Massachusetts (the “Facility”), and associated assets…

Termination of a Material Definitive Agreement. The information required by this item is included in

Other Events. On June 20, 2024, the company issued a press release announcing the Registered Direct Offering and the Private Placement. The full text of the press release is attached as Exhibit 99.1 to this Current Report on Form 8-K and incorporated herein by reference. On June 21, 2024, the Company issued a press release announcing the closing of the Registered Direct Offering and the Private Placement. The full text of the press release is attached as Exhibit 99.2 to this Current Report on…

Entry into a Material Definitive Agreement. On June 19, 2024, Mustang Bio, Inc. (the “ Company ”) entered into a Securities Purchase Agreement (the “ Purchase Agreement ”) with a single institutional accredited investor (the “ Investor ”) pursuant to which the Company agreed to issue and sell, in a registered direct offering priced at-the-market under the rules of The Nasdaq Stock Market (the “ Registered Direct Offering ”), (i) 3,025,000 shares (the “ Shares ”) of common stock of the Company…

Based in part upon the representations of the Investor in the Purchase Agreement, the offering and sale of the Warrants is exempt from registration under Section 4(a)(2) of the Securities Act of 1933, as amended (the “ Securities Act ”), Rule 506 of Regulation D promulgated under the Securities Act, and corresponding provisions of state securities or “blue sky” laws. The sale of the Warrants by the Company in the Private Placement and the Wainwright Warrants has not been registered under the…

Notice of Delisting of Failure to Satisfy a Continued Listing Rule or Standard; Transfer of Listing. ​ On May 16, 2024, Mustang Bio, Inc. (the “Company”) received a notice (the “Second Letter”) from the Listing Qualifications Department (the “Staff”) of The Nasdaq Stock Market LLC (“Nasdaq”) indicating 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 31 consecutive business days and, as a result, the Company i…

Other Events ​ As previously disclosed, on March 13, 2024, the Company received a notice (the “First Letter”) from the Staff of Nasdaq notifying the Company that it was not in compliance with the minimum $2.5 million stockholders’ equity requirement nor the alternative quantitative standards for continued listing on the Nasdaq Capital Market as set forth under Nasdaq Listing Rule 5550(b)(1). The First Letter had no immediate effect on the Company’s continued listing on Nasdaq. ​ In accordance…

Entry Into a Material Definitive Agreement. Securities Purchase Agreement On April 29, 2024, Mustang Bio, Inc. (the “Company”) commenced a best efforts public offering (the “Offering”) of an aggregate of (i) 1,160,000 shares (the “Shares”) of common stock, par value $0.0001 per share ( “Common Stock”), of the Company, (ii) pre-funded warrants (the “Pre-Funded Warrants”) to purchase up to an aggregate of 15,717,638 shares of Common Stock (the “Pre-Funded Warrant Shares”), (iii) Series A-1 warr…

Results of Operations and Financial Condition. On April 29, 2024, in connection with the filing of Amendment No. 2 to the Registration Statement on Form S-1 of Mustang Bio, Inc. (the “Company” or “we”), the Company disclosed the following: Based on information currently available, we estimate that as of March 31, 2024, cash and cash equivalents were approximately $1.3 million, and cash used in operating activities for the first quarter of 2024 was $5.3 million. Our estimate of our cash and ca…

Costs Associated with Exit or Disposal Activities. ​ On April 10, 2024, the board of directors of Mustang Bio, Inc. (“Mustang”) approved a reduction of its workforce by approximately 81% of its employee base in order to reduce costs and preserve capital due to the fundraising environment and continued uncertainty regarding the U.S. Committee on Foreign Investment in the United States (“CFIUS”) review of the sale of the Company’s leasehold interest in its cell processing facility located in Wo…

Notice of Delisting or Failure to Satisfy a Continued Listing Rule or Standard; Transfer of Listing. On March 13, 2024, Mustang Bio, Inc. (the “Company”) received a deficiency letter (the “Letter”) from the Listing Qualifications Department (the “Staff”) of The Nasdaq Stock Market LLC (“Nasdaq”) notifying the Company that it was not in compliance with the minimum stockholders’ equity requirement for continued listing on the Nasdaq Capital Market under Nasdaq Listing Rule 5550(b)(1). Nasdaq Li…