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

Rhea-AI Filing Summary

Moleculin Biotech (MBRX) filed a Form 4 for EVP & CFO Jonathan P. Foster reporting equity awards dated 11/12/2025. The filing lists a stock option for 600,000 shares at an exercise price of $0.49, expiring 11/12/2035, vesting in four equal annual installments beginning on the first anniversary. It also reports 400,000 performance-based RSUs that vest in 20% increments upon achievement of specified clinical milestones; 100% vest upon a change of control as defined in the 2024 Stock Plan. Following these transactions, derivative securities beneficially owned were 2,017,695, held directly.

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

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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).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Foster Jonathan P.

(Last) (First) (Middle)

C/O MOLECULIN BIOTECH, INC.

5300 MEMORIAL DR., SUITE 950

(Street)

HOUSTON TX 77007

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Moleculin Biotech, Inc. [ MBRX ]

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

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

3. Date of Earliest Transaction (Month/Day/Year)
11/12/2025

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

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
Stock option (right to buy)	$0.49	11/12/2025		A		600,000		(1)	11/12/2035	Common Stock	600,000	(2)	1,617,695	D
Performance Based Restricted Stock Units	(3)	11/12/2025		A		400,000		(4)	11/12/2035	Common Stock	400,000	(2)	2,017,695	D

Explanation of Responses:

1. The stock option set forth in this table vests in four equal annual installments beginning on the first anniversary of the Transaction Date, subject to the grantee's continued service to the Company on each vesting date.

2. Issued in connection with the reporting person's employment with the Company.

3. Each restricted stock unit represents a contingent right to receive one shares of Company common stock.

4. On November 12, 2025, the Board approved this performance based restricted stock unit. The performance based restricted stock units set forth in this table will vest in 20% installments upon the achievement of certain clinical milestones; provided that upon a change of control (as defined in the 2024 Stock Plan) 100% shall vest.

	/s/ Jonathan P. Foster	11/14/2025
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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