Acrivon CEO, EVP sell 1,713 shares for tax withholding

Acrivon Therapeutics, Inc. (ACRV) reported insider transactions involving President and CEO Dr. Peter Blume-Jensen and EVP Dr. Kristina Masson.

Rhea-AI Filing Summary

Acrivon Therapeutics, Inc. (ACRV) reported insider transactions involving President and CEO Dr. Peter Blume-Jensen and EVP Dr. Kristina Masson. On 2026-08-18, a total of 1,713 shares of Common Stock were sold at $2.01 per share to satisfy a mandatory tax withholding requirement upon vesting of restricted stock units.

Of these, 1,229 shares were sold from shares held by Dr. Blume-Jensen, leaving 2,244,088 shares held directly. Another 484 shares were sold from shares held by Dr. Masson, leaving 385,859 shares held indirectly, with each spouse disclaiming beneficial ownership of the other’s securities except for their pecuniary interest.

Insider Trade Summary

Net Seller: 1,713 shares

Net Sell 2 txns

Insider Blume-Jensen Peter, Masson Kristina

Role President and CEO | EVP - Business Operations

Sold 1,713 shs ($3K)

Type	Security	Shares	Price	Value
Sale	Common Stock F1, F2	1,229	$2.01	$2K
Sale	Common Stock F1, F3	484	$2.01	$972.84

Holdings After Transaction: Common Stock — 2,244,088 shares (Direct); Common Stock — 385,859 shares (Indirect, See Footnote)

Footnotes (3)

1. F1. Shares sold automatically to satisfy the mandatory tax withholding requirement upon vesting of restricted stock units.
2. F2. These securities are held by President and CEO, Dr. Peter Blume-Jensen, who is also Dr. Kristina Masson's spouse. Dr. Masson disclaims beneficial ownership of such securities except to the extent of her pecuniary interest therein.
3. F3. These securities are held by co-founder and EVP, Dr. Kristina Masson, who is also Dr. Blume-Jensen's spouse. Dr. Blume-Jensen disclaims beneficial ownership of such securities except to the extent of his pecuniary interest therein.

Key Figures

Total shares sold: 1,713 shares Sale price per share: $2.01 per share Shares sold from Blume-Jensen holdings: 1,229 shares +3 more

6 metrics

Total shares sold 1,713 shares Common Stock sold on 2026-08-18 to satisfy mandatory tax withholding

Sale price per share $2.01 per share Price for both reported Common Stock sales on 2026-08-18

Shares sold from Blume-Jensen holdings 1,229 shares Common Stock sold from shares held by Dr. Peter Blume-Jensen

Direct holdings after Blume-Jensen transaction 2,244,088 shares Common Stock held directly by Dr. Peter Blume-Jensen after sale

Shares sold from Masson holdings 484 shares Common Stock sold from shares held by Dr. Kristina Masson

Indirect holdings after Masson-related transaction 385,859 shares Common Stock reported as held indirectly after sale of 484 shares

Key Terms

mandatory tax withholding requirement, restricted stock units, pecuniary interest, beneficial ownership

4 terms

mandatory tax withholding requirement financial

"Shares sold automatically to satisfy the mandatory tax withholding requirement"

restricted stock units financial

"mandatory tax withholding requirement upon vesting of 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.

pecuniary interest financial

"disclaims beneficial ownership of such securities except to the extent of her pecuniary interest"

beneficial ownership financial

"disclaims beneficial ownership of such securities except to the extent"

Beneficial ownership means the person or entity that actually enjoys the benefits of owning shares or other assets — such as receiving dividends, voting rights, or price gains — even if the legal title is held in another name. For investors it matters because knowing who truly controls and profits from a company reveals who can influence decisions, exposes potential conflicts of interest or hidden concentration of power, and affects transparency and risk in the stock.

FAQ

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

What insider transactions were reported for ACRV on this Form 4?

The filing reports the sale of 1,713 shares of Acrivon Therapeutics, Inc. Common Stock at $2.01 per share on 2026-08-18, executed to satisfy the mandatory tax withholding requirement upon vesting of restricted stock units.

How many ACRV shares did Peter Blume-Jensen sell and how many does he still hold?

Dr. Peter Blume-Jensen had 1,229 shares sold to cover tax withholding. After this transaction, 2,244,088 shares of Acrivon Therapeutics Common Stock are reported as held directly by him.

What ACRV shares related to Kristina Masson were involved in this Form 4?

A total of 484 shares of Acrivon Therapeutics Common Stock held by Dr. Kristina Masson were sold to satisfy mandatory tax withholding, leaving 385,859 shares reported as held indirectly. Dr. Blume-Jensen disclaims beneficial ownership except for his pecuniary interest.

Were the ACRV insider sales part of a discretionary trading plan?

No. The document-level Rule 10b5-1 checkbox is unchecked, and a footnote states the shares were sold automatically to satisfy mandatory tax withholding upon restricted stock unit vesting, rather than as discretionary open-market sales for investment purposes.

How is beneficial ownership between the ACRV executives and their spouse handled in this filing?

The filing states each spouse disclaims beneficial ownership of securities held by the other, except to the extent of their pecuniary interest. Shares are reported as held by Dr. Blume-Jensen or Dr. Masson, with cross-disclaimers reflecting their respective economic interests.

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

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Accepted by SEC EDGAR 08/20/2026 - 04:07 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^*

Blume-Jensen Peter

(Last) (First) (Middle)

C/O ACRIVON THERAPEUTICS, INC.

480 ARSENAL WAY, SUITE 100

(Street)

WATERTOWN MASSACHUSETTS 02472

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
Acrivon Therapeutics, Inc. [ ACRV ]

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

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
08/18/2026

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

	Form filed by One Reporting Person
X	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	08/18/2026		S(1)		1,229	D	$2.01	2,244,088	D(2)
Common Stock	08/18/2026		S(1)		484	D	$2.01	385,859	I	See Footnote(3)

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

1. Name and Address of Reporting Person^*

Blume-Jensen Peter

(Last) (First) (Middle)

C/O ACRIVON THERAPEUTICS, INC.

480 ARSENAL WAY, SUITE 100

(Street)

WATERTOWN MASSACHUSETTS 02472

(City) (State) (Zip)

UNITED STATES

(Country)

Relationship of Reporting Person(s) to Issuer

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

1. Name and Address of Reporting Person^*

Masson Kristina

(Last) (First) (Middle)

C/O ACRIVON THERAPEUTICS, INC.

480 ARSENAL WAY, SUITE 100

(Street)

WATERTOWN MASSACHUSETTS 02472

(City) (State) (Zip)

UNITED STATES

(Country)

Relationship of Reporting Person(s) to Issuer

X	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	EVP - Business Operations

Explanation of Responses:

1. Shares sold automatically to satisfy the mandatory tax withholding requirement upon vesting of restricted stock units.

2. These securities are held by President and CEO, Dr. Peter Blume-Jensen, who is also Dr. Kristina Masson's spouse. Dr. Masson disclaims beneficial ownership of such securities except to the extent of her pecuniary interest therein.

3. These securities are held by co-founder and EVP, Dr. Kristina Masson, who is also Dr. Blume-Jensen's spouse. Dr. Blume-Jensen disclaims beneficial ownership of such securities except to the extent of his pecuniary interest therein.

	/s/ Adam D. Levy, Attorney-in-Fact for Peter Blume-Jensen	08/20/2026
	/s/ Adam D. Levy, Attorney-in-Fact for Kristina Masson	08/20/2026
	** 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)