Company: MBIO
Filing Date: 2025-04-04
Form Type: POS AM
Source: 0001104659-25-032236
Chunk: 1

Company: MUSTANG BIO, INC.
Filing Date: 2025-04-04
Form: POS AM
Chunk 1
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 the earlier effective registration statement for the same offering. ¨

If this Form is a post-effective amendment
filed pursuant to Rule 462(d) under the Securities Act, check the following box and list the Securities Act registration statement
number of the earlier effective registration statement for the same offering. ¨

Indicate by check mark whether the registrant
is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company or an emerging growth company.
See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,”
and “emerging growth company” in Rule 12b-2 of the Exchange Act.

| Large accelerated filer ¨ |     | Accelerated filer ¨         |
| Non-accelerated filer x   |     | Smaller reporting company x |
|                           |     | 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 7(a)(2)(B) of the Securities Act. ¨

The registrant hereby amends this Registration Statement on such date or dates as may be necessary to delay its effective date until the Registrant shall file a further amendment which specifically states that this Registration Statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933 or until the Registration Statement shall become effective on such date as the Commission, acting pursuant to said Section 8(a), may determine.

<div align='center'>EXPLANATORY NOTE</div>

This Post-Effective Amendment No. 2 (this “Amendment”) to the Registration Statement on Form S-1, as amended (File No. 333-284299) (the “Original Registration Statement”), of Mustang Bio, Inc. (the “Company”) is being filed pursuant to the undertakings in the Original Registration Statement to update and supplement the information contained in the Original Registration Statement, which was originally declared effective by the Securities and Exchange Commission (the “SEC”) on February 5, 2025.

The Original Registration Statement, as amended by this Amendment, pertains solely to the registration of 6,697,889 shares of common stock, par value $0.0001 per share, underlying warrants previously issued by the Company in connection with its public offering that closed on