[Form 4] Fortress Biotech, Inc. Insider Trading Activity

Rhea-AI Filing Summary

Fortress Biotech, Inc. (reporting person) reported a Section 16 filing related to Mustang Bio, Inc. (MBIO). On 09/29/2025 the reporting person received 59,334 shares of Mustang Bio common stock at a reported price of $0, increasing its beneficial ownership to 258,192 shares. The filing states these shares were granted under an agreement that awards the reporting person equity equal to 2.5% of the gross proceeds of any debt or equity financing; the grant followed the issuer’s receipt of proceeds from the exercise of previously issued warrants. The Form 4 is signed by an attorney-in-fact for the reporting person on 10/01/2025.

Positive

• Equity alignment: Reporting person received shares tied to financing activity, aligning interests with issuer following warrant exercises
• Clear disclosure: Form 4 documents transaction date, share amount (59,334), and post-transaction ownership (258,192)

Negative

• Potential dilution: Issuance of shares as a financing fee increases outstanding shares and may dilute existing shareholders, though the filing does not quantify the dilution magnitude

Insights

Financial Analyst

TL;DR Insider received a non‑cash equity grant tied to financing activity, modestly increasing ownership to 258,192 shares.

The 59,334 shares were granted rather than purchased, at a reported price of $0, under a contractual entitlement equal to 2.5% of gross financing proceeds. This is a transaction that reflects contractual compensation for origination/placement activity rather than market purchases. The issuance increased beneficial holdings but did not involve cash consideration from the reporting person. For investors, the item is a disclosure of insider-aligned economics with financing activity; the filing contains no details on the dollar amount of the financing or dilution percentage relative to outstanding shares.

Corporate Governance Expert

TL;DR Governance disclosure shows an equity fee paid to a related party tied to financings; documentation appears properly disclosed on Form 4.

The filing clearly explains the contractual basis for the grant (2.5% of gross proceeds) and records the resulting share count. The Form 4 includes signature by an attorney-in-fact and a post-transaction beneficial ownership total. The disclosure is timely and describes the nature of the indirect compensation, but the form does not quantify the underlying financing size or the potential governance implications such as dilution magnitude or related-party conflict specifics.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person^*

Fortress Biotech, Inc.

(Last) (First) (Middle)

1111 KANE CONCOURSE SUITE 301

(Street)

BAY HARBOR ISLANDS FL 33154

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
MUSTANG BIO, INC. [ MBIO ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director	X	10% Owner
	Officer (give title below)		Other (specify below)

3. Date of Earliest Transaction (Month/Day/Year)
09/29/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
COMMON STOCK, PAR VALUE $0.0001	09/29/2025		A		59,334(1)	A	$0	258,192	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. The Issuer is required to grant to the Reporting Person an equity fee in shares of the Issuer's Common Stock equal to 2.5% of the gross amount of any debt or equity financing consummated by the Issuer. These shares were granted by the Issuer to the Reporting Person following the receipt of proceeds by the Issuer upon the exercise of warrants previously issued by the Issuer.

	/s/ Samuel Berry, Attorney-in-Fact	10/01/2025
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
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FAQ

What did the Form 4 filed for Mustang Bio (MBIO) disclose?

The Form 4 discloses a grant of 59,334 common shares on 09/29/2025, at a reported price of $0, bringing the reporting person’s total to 258,192 shares.

Why were the 59,334 shares granted to the reporting person?

The filing states the shares were granted under an agreement awarding the reporting person equity equal to 2.5% of the gross proceeds from any debt or equity financing; these shares were issued after the issuer received proceeds from warrant exercises.

Did the reporting person pay cash for the shares reported on Form 4?

No. The transaction is reported with a price of $0, indicating the shares were granted rather than purchased for cash.

Who filed the Form 4 on behalf of the reporting person?

The Form 4 is signed by Samuel Berry, Attorney-in-Fact, with signature dated 10/01/2025.

Does the Form 4 disclose the size of the financing that triggered the grant?

No. The Form 4 explains the 2.5% entitlement but does not provide the dollar amount of the underlying financing or total shares outstanding for dilution calculation.