Compass Therapeutics counsel buys 25,000 shares

Compass Therapeutics General Counsel Jonathan Anderman purchased 25,000 shares of common stock in an open-market transaction at $1.89 per share.

Rhea-AI Filing Summary

Compass Therapeutics General Counsel Jonathan Anderman purchased 25,000 shares of common stock in an open-market transaction at $1.89 per share. After this buy, he directly holds 196,000 shares. 150,000 of these shares are unvested restricted stock units granted on January 2, 2026, which vest in four equal annual installments starting January 2, 2027, subject to service-based vesting conditions.

Insider Trade Summary

Net Buyer: 25,000 shares

Net Buy 1 txn

Insider Anderman Jonathan

Role General Counsel

Bought 25,000 shs ($47K)

Type	Security	Shares	Price	Value
Purchase	Common Stock	25,000	$1.89	$47K

Holdings After Transaction: Common Stock — 196,000 shares (Direct)

Footnotes (1)

1. F1. 150,000 of the shares represents unvested restricted stock units ("RSU") granted on January 2, 2026. Each RSU represents a contingent right to receive one share of common stock. The award is subject to service-based vesting conditions and vests in four equal annual installments, with the first installment vested on January 2, 2027.

Key Figures

Shares purchased: 25,000 shares Purchase price: $1.89 per share Total shares after transaction: 196,000 shares +2 more

5 metrics

Shares purchased 25,000 shares Open-market purchase on April 29, 2026

Purchase price $1.89 per share Open-market transaction

Total shares after transaction 196,000 shares Direct ownership following purchase

Unvested RSUs 150,000 units Granted January 2, 2026

RSU vesting structure 4 equal annual installments First installment vests January 2, 2027

Key Terms

restricted stock units ("RSU"), service-based vesting conditions, open-market purchase

3 terms

restricted stock units ("RSU") financial

"150,000 of the shares represents unvested restricted stock units ("RSU") granted on January 2, 2026."

service-based vesting conditions financial

"The award is subject to service-based vesting conditions and vests in four equal annual installments"

open-market purchase financial

"transaction_action": "open-market purchase""

An open-market purchase is when an investor or a company buys shares on a public stock exchange at the going market price, rather than through a private deal. It matters to investors because these purchases change how many shares are available, can push the stock price up or signal confidence from large buyers, and often affect per-share metrics like earnings—think of it like someone buying lots of apples off a grocery shelf, reducing supply and potentially raising the price.

FAQ

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

What did Compass Therapeutics (CMPX) insider Jonathan Anderman do in this Form 4/A?

Jonathan Anderman, General Counsel of Compass Therapeutics, bought 25,000 shares of common stock in an open-market transaction at $1.89 per share. This filing updates his holdings and discloses additional equity compensation details, including unvested restricted stock units.

How many Compass Therapeutics (CMPX) shares does Jonathan Anderman hold after this transaction?

After the reported purchase, Jonathan Anderman directly holds 196,000 Compass Therapeutics common shares. This total includes 150,000 unvested restricted stock units granted on January 2, 2026, which represent a contingent right to receive common stock if vesting conditions are met.

At what price did Compass Therapeutics (CMPX) insider shares trade in this Form 4/A transaction?

The Form 4/A shows Jonathan Anderman bought 25,000 Compass Therapeutics common shares at $1.89 per share. This was classified as an open-market or private purchase, indicating he paid cash at that per-share price to increase his direct equity position.

What are the terms of Jonathan Anderman’s restricted stock units in CMPX?

Jonathan Anderman holds 150,000 unvested restricted stock units granted on January 2, 2026. Each RSU is a contingent right to one common share and is subject to service-based vesting in four equal annual installments, beginning on January 2, 2027.

Does this Compass Therapeutics (CMPX) Form 4/A involve any derivative securities or options?

The provided Form 4/A data shows only a non-derivative open-market purchase of common stock and lists no derivative transactions. His remaining equity exposure includes 150,000 unvested restricted stock units, rather than options or other derivative securities.

How do the RSUs affect Jonathan Anderman’s future Compass Therapeutics (CMPX) share ownership?

The 150,000 restricted stock units could convert into common stock over time if service-based conditions are satisfied. They vest in four equal annual tranches starting January 2, 2027, potentially increasing his delivered share ownership gradually as each installment vests.

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

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Accepted by SEC EDGAR 04/30/2026 - 04:00 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^*

Anderman Jonathan

(Last) (First) (Middle)

C/O COMPASS THERAPEUTICS, INC.

80 GUEST STREET, SUITE 601

(Street)

BOSTON MASSACHUSETTS 02135

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
Compass Therapeutics, Inc. [ CMPX ]

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

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
04/29/2026

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)
04/29/2026

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	04/29/2026		P		25,000	A	$1.89	196,000(1)	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. 150,000 of the shares represents unvested restricted stock units ("RSU") granted on January 2, 2026. Each RSU represents a contingent right to receive one share of common stock. The award is subject to service-based vesting conditions and vests in four equal annual installments, with the first installment vested on January 2, 2027.

Remarks:

Explanatory Note: This amendment is being filed to correct the transaction code reported in Table I of the original Form 4 filed on April 29, 2026. The transaction was inadvertently reported using transaction code A. The correct transaction code is P, which reflects that the transaction was an open market purchase. All other information in the original filing remains unchanged.

	/s/ Neil Lerner attorney-in-fact	04/30/2026
	** 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)