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): September 10, 2024

Mustang Bio, Inc.

(Exact Name of Registrant as Specified in Charter)

377 Plantation Street

Worcester, Massachusetts 01605

(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:

Securities registered pursuant to Section 12(b) of the Act:

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 3.01. 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 5550(b) (the “Rule”). The Company was unable to demonstrate compliance with the Rule by that date.

Accordingly, on September 10, 2024, the Staff formally notified the Company that it had determined to delist the Company’s securities from Nasdaq based upon the Company’s continued non-compliance with the Rule unless the Company timely requests a hearing before the Nasdaq Hearings Panel (the “Panel”). The Company intends to timely request a hearing before the Panel, which request will stay any further action by Nasdaq at least pending completion of the hearing and the expiration of any extension that may be granted by the Panel to the Company following the hearing.

The Company is considering all options available to it to regain compliance with the Rule; however, there can be no assurance that the Panel will grant the Company’s request for continued listing or that the Company will be able to evidence compliance with the Rule within any extension period that may be granted by the Panel.

Neither the Staff’s notification nor the Company’s noncompliance with the Rule have an immediate effect on the listing or trading of the Company’s common stock, par value $0.0001 per share, which will continue to trade on The Nasdaq Capital Market under the symbol “MBIO.”

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, expectations, strategies, predictions or any other statements relating to the Company’s future activities or other future events or conditions, including its intention to request a hearing before the Nasdaq Hearing Panel, its ability to regain or sustain compliance with Nasdaq’s stockholders’ equity requirement in a timely manner or at all, and its ability to maintain compliance with Nasdaq’s other continued listing standards, are forward-looking statements. The words “anticipate,” “believe,” “continue,” “could,” “estimate,” “expect,” “intend,” “may,” “plan,” “predict,” “project,” “will,” “should,” “would” and similar expressions are intended to identify forward-looking statements. These statements are based on current expectations, estimates and projections made by management about the Company’s business, its industry and other conditions affecting the Company’s financial condition, results of operations or business prospects. These statements are not guarantees of future performance and involve risks, uncertainties and assumptions that are difficult to predict. Therefore, actual outcomes and results may differ materially from what is expressed or forecasted in, or implied by, the forward-looking statements due to numerous risks and uncertainties. Factors that could cause such outcomes and results to differ include, but are not limited to, those risks discussed in the Company’s filings which it makes with the Securities and Exchange Commission. Any forward-looking statements speak only as of the date on which they are made, and the Company undertakes no obligation to publicly update or revise any forward-looking statements to reflect events or circumstances that may arise after the date of this Current Report on Form 8-K, except as required by applicable law. Investors should evaluate any statements made by the Company in light of these important factors.

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.