Moleculin CEO Walter Klemp Grows Stake Despite Tax-Related Share Sales

Filing Impact

(Moderate)

Filing Sentiment

(Neutral)

Form Type

Rhea-AI Filing Summary

Walter V. Klemp, CEO, President and Director of Moleculin Biotech (MBRX), reported multiple transactions on June 16, 2025:

Acquired 1,667 shares of common stock through the conversion of Restricted Stock Units (RSUs)
Subsequently disposed of 406 shares at $0.6852 per share for tax withholding purposes
Following these transactions, Klemp directly owns 58,296 shares of common stock
Maintains ownership of 370,075 RSUs from a June 16, 2021 grant that vests in four equal annual installments

These transactions represent the scheduled vesting of previously awarded RSUs, with partial share withholding to cover tax obligations. The filing indicates routine executive compensation activity rather than open market transactions.

Insider Trade Summary

1,667 shares exercised/converted

Mixed 3 txns

Insider KLEMP WALTER V

Role CEO and President

Type	Security	Shares	Price	Value
Exercise	Restricted Stock Units	1,667	$0.00	--
Exercise	Common Stock	1,667	$0.00	--
Tax Withholding	Common Stock	406	$0.6852	$278.19

Holdings After Transaction: Restricted Stock Units — 370,075 shares (Direct); Common Stock — 58,702 shares (Direct)

Footnotes (1)

Restricted stock units convert into common stock on a one-for-one basis. Shares withheld for payment of taxes upon vesting of restricted stock unit awards On June 16, 2021, the reporting person was granted 6,668 restricted stock units, vesting in four equal annual installments beginning on the first anniversary of the grant date.

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Form 4 Insider Transactions: What Each Field Means →

06/18/2025 - 09:00 PM

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^*

KLEMP WALTER V

(Last)

(First)

(Middle)

C/O MOLECULIN BIOTECH, INC.

5300 MEMORIAL DR., SUITE 950

(Street)

HOUSTON

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)

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

3. Date of Earliest Transaction (Month/Day/Year)
06/16/2025

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)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Stock	06/16/2025		M		1,667	A	⁽¹⁾	58,702	D
Common Stock	06/16/2025		F		406⁽²⁾	D	$0.6852	58,296	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)
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)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
Restricted Stock Units	⁽¹⁾	06/16/2025		M			1,667	⁽³⁾	⁽³⁾	Common Stock	1,667	$0	370,075	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 June 16, 2021, the reporting person was granted 6,668 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	06/18/2025
	** 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.
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.

Source: View Original Filing on SEC EDGAR

FAQ

How many MBRX shares did CEO Walter Klemp acquire on June 16, 2025?

CEO Walter Klemp acquired 1,667 shares of MBRX common stock on June 16, 2025 through the conversion of restricted stock units (RSUs). However, 406 shares were withheld for tax purposes, resulting in a net acquisition of 1,261 shares.

What is the current ownership position of MBRX CEO Walter Klemp after the June 2025 transaction?

After the reported transactions on June 16, 2025, Walter Klemp directly owns 58,296 shares of MBRX common stock. He also holds 370,075 restricted stock units that can convert to common stock.

What was the vesting schedule for MBRX CEO's restricted stock units granted in 2021?

The restricted stock units were originally granted on June 16, 2021, with a total of 6,668 RSUs vesting in four equal annual installments beginning on the first anniversary of the grant date. This June 2025 transaction represents the final vesting installment.

What price were MBRX shares withheld for tax purposes in the June 2025 transaction?

The 406 shares withheld for tax payments were valued at $0.6852 per share according to the Form 4 filing.

What positions does Walter Klemp hold at MBRX according to the Form 4?

According to the Form 4, Walter V. Klemp serves as both a Director and an Officer (specifically CEO and President) of Moleculin Biotech, Inc. (MBRX).