Moleculin Biotech's Donald H. Picker acquires 17 shares

Picker's 70 restricted stock units were granted in November 2024 and vest in four equal annual installments beginning on the first anniversary.

Available on EDGAR 11/06/2026 - 05:03 PM EST Accepted by SEC EDGAR 11/06/2026 - 05:03 PM EST Learn about SEC filing dates

Rhea-AI Filing Summary

Moleculin Biotech, Inc. Chief Science Officer Donald H. Picker reported a conversion of 18 restricted stock units and an acquisition of 17 common shares on November 4, 2026. Four common shares were withheld for taxes upon vesting at $8.46 per share. The reported position following the transaction was 39,474 restricted stock units.

Insider Trade Summary

18 shares exercised/converted

Exercise 3 txns

Insider PICKER DONALD H

Role Chief Science Officer

Type	Security	Shares	Price	Value
Exercise	Restricted Stock Units F1, F3	18	$0.00	$0.00
Exercise	Common Stock F1	17	--	--
Tax Withholding	Common Stock F2	4	$8.46	$33.84

Holdings After Transaction: Restricted Stock Units — 39,474 contracts (Direct); Common Stock — 8,718 shares (Direct)

Holdings Before and After: Restricted Stock Units, 39,492 to 39,474 contracts (Direct); Common Stock, 8,705 to 8,718 shares (Direct)

Footnotes (3)

1. F1. Restricted stock units convert into common stock on a one-for-one basis.
2. F2. Shares withheld for payment of taxes upon vesting of restricted stock unit awards.
3. F3. On November 4, 2024, the reporting person was granted 70 restricted stock units, vesting in four equal annual installments beginning on the first anniversary of the grant date.

Key Figures

Restricted stock units converted: 18 restricted stock units Common shares acquired: 17 shares Shares withheld for taxes: 4 shares +3 more

6 metrics

Restricted stock units converted 18 restricted stock units November 4, 2026

Common shares acquired 17 shares November 4, 2026

Shares withheld for taxes 4 shares Upon vesting on November 4, 2026

Price per share for tax withholding $8.46 per share November 4, 2026

Restricted stock units following transaction 39,474 restricted stock units Following the November 4, 2026 transaction

Restricted stock units granted 70 restricted stock units Granted November 4, 2024

Key Terms

restricted stock units, vesting, withheld for payment of taxes

3 terms

restricted stock units financial

"Restricted stock units convert into common stock on a one-for-one basis."

Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.

vesting financial

"Shares withheld for payment of taxes upon vesting"

Vesting is the process by which you earn full ownership of something, like company stock or a retirement benefit, over time. It’s like earning the right to keep a gift piece by piece the longer you stay with a company, making sure employees stay committed before they receive all the benefits.

withheld for payment of taxes financial

"Shares withheld for payment of taxes upon vesting"

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What stock transactions did MBRX Chief Science Officer Donald H. Picker report?

Picker reported the conversion of 18 restricted stock units and the acquisition of 17 common shares on November 4, 2026. Four common shares were withheld for taxes upon vesting at $8.46 per share; the reported position following the transaction was 39,474 restricted stock units.

When do Donald H. Picker's MBRX restricted stock units vest?

Picker's 70 restricted stock units were granted on November 4, 2024, and vest in four equal annual installments beginning on the first anniversary of the grant date.

AI-generated analysis. How Rhea-AI works. Not financial advice.

Form 4 Insider Transactions: What Each Field Means →

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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

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

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^*

PICKER DONALD H

(Last) (First) (Middle)

C/O MOLECULIN BIOTECH, INC.

5300 MEMORIAL DR., SUITE 950

(Street)

HOUSTON TEXAS 77007

(City) (State) (Zip)

UNITED STATES

(Country)

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)
	Chief Science Officer

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
11/04/2026

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

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

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

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	11/04/2026		M		17	A	(1)	8,722	D
Common Stock	11/04/2026		F		4(2)	D	$8.46	8,718	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
Restricted Stock Units	(1)	11/04/2026		M			18	(3)	(3)	Common Stock	17	$0	39,474	D

Explanation of Responses:

1. Restricted stock units convert into common stock on a one-for-one basis.

2. Shares withheld for payment of taxes upon vesting of restricted stock unit awards.

3. On November 4, 2024, the reporting person was granted 70 restricted stock units, vesting in four equal annual installments beginning on the first anniversary of the grant date.

	/s/ Jonathan P. Foster by Power of Attorney	11/06/2026
	** 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.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)