Monopar Therapeutics withholds 597 CEO shares for tax

The post-transaction position includes 104,127 directly held shares and 62,815 shares held indirectly by the Chandler D. Robinson Irrevocable Trust.

Rhea-AI Filing Summary

Monopar Therapeutics (MNPR) reports that CEO and director Chandler Robinson had 597 common shares withheld by the issuer on October 20, 2026, to pay applicable withholding tax. The additional withholding was due to an administrative error in connection with the vesting and settlement of 12,873 restricted stock units on June 30, 2026. Robinson’s reported direct holdings after the transaction were 104,127 shares. The Chandler D. Robinson Irrevocable Trust U/A dated May 20, 2020, was separately reported as holding 62,815 shares indirectly.

Insider Trade Summary

Tax Withholding: 597 shares

Tax Withholding 2 txns

Insider Robinson Chandler

Role Chief Executive Officer

Type	Security	Shares	Price	Value
Tax Withholding	Common Stock F1	597	$92.59	$55K
holding	Common Stock F2	--	--	--

Holdings After Transaction: Common Stock — 104,127 shares (Direct); Common Stock — 62,815 shares (Indirect, See Footnote)

Footnotes (2)

1. F1. Represents additional shares withheld by the issuer to pay for the applicable withholding tax due to administrative error in connection with the vesting and settlement of 12,873 restricted stock units on June 30, 2026, as reported on a Form 4 filed July 2, 2026.
2. F2. Represents shares held by the Chandler D. Robinson Irrevocable Trust U/A dated May 20, 2020.

Key Figures

Shares withheld for withholding tax: 597 shares Reported transaction price per share: $92.59 per share Direct holdings after transaction: 104,127 shares +2 more

5 metrics

Shares withheld for withholding tax 597 shares Common shares withheld on October 20, 2026

Reported transaction price per share $92.59 per share Price reported for the October 20, 2026 share-withholding transaction

Direct holdings after transaction 104,127 shares Chandler Robinson’s reported direct position

Indirect trust holdings 62,815 shares Chandler D. Robinson Irrevocable Trust U/A dated May 20, 2020

Restricted stock units 12,873 units Vested and settled on June 30, 2026

Key Terms

restricted stock units, withholding tax, vesting and settlement

3 terms

restricted stock units financial

"vesting and settlement of 12,873 restricted stock units"

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.

withholding tax financial

"pay for the applicable withholding tax"

Withholding tax is a government-required portion of a payment—such as dividends, interest, or salary—that the payer keeps back and sends directly to tax authorities before the recipient receives the money. For investors it reduces the cash they actually get and changes the after-tax return on an investment; rates and refund or credit rules vary by country and can materially affect comparisons between similar investments, like a cashier holding part of a bill to cover taxes.

vesting and settlement financial

"in connection with the vesting and settlement"

FAQ

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

How many MNPR shares were withheld from CEO Chandler Robinson?

The issuer withheld 597 common shares on October 20, 2026, to pay applicable withholding tax. The additional withholding was tied to an administrative error involving the vesting and settlement of 12,873 restricted stock units on June 30, 2026.

How many shares did Chandler Robinson and his trust hold after the MNPR transaction?

Chandler Robinson’s reported direct holdings after the transaction were 104,127 shares. The Chandler D. Robinson Irrevocable Trust U/A dated May 20, 2020, was separately reported as holding 62,815 shares indirectly.

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

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Available on EDGAR 10/20/2026 - 04:59 PM EDT Accepted by SEC EDGAR 10/20/2026 - 04:59 PM EDT Learn about SEC filing dates

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^*

Robinson Chandler

(Last) (First) (Middle)

1000 SKOKIE BLVD SUITE 350

(Street)

WILMETTE ILLINOIS 60091

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
Monopar Therapeutics [ MNPR ]

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

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
10/20/2026

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	10/20/2026		F		597(1)	D	$92.59	104,127	D
Common Stock								62,815	I	See Footnote(2)

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. Represents additional shares withheld by the issuer to pay for the applicable withholding tax due to administrative error in connection with the vesting and settlement of 12,873 restricted stock units on June 30, 2026, as reported on a Form 4 filed July 2, 2026.

2. Represents shares held by the Chandler D. Robinson Irrevocable Trust U/A dated May 20, 2020.

	/s/ Quan Vu, Attorney-in-fact	10/20/2026
	** 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)