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  4. [Form 4] Acrivon Therapeutics, Inc. Insider Trading Activity

Acrivon (ACRV) CEO and EVP report RSU-related tax withholding move

Filing Impact
(Neutral)
Filing Sentiment
(Neutral)
Form Type
4

Rhea-AI Filing Summary

Acrivon Therapeutics reported a routine insider equity adjustment involving its President and CEO, Dr. Peter Blume-Jensen, and EVP of Business Operations, Dr. Kristina Masson. The company withheld 13,729 shares of common stock at $1.79 per share to cover mandatory taxes upon the vesting of restricted stock units, a non‑market transaction classified as a tax-withholding disposition. Following this, Dr. Blume-Jensen directly holds 2,245,317 shares of common stock, and the filing also lists 386,343 shares of common stock as indirectly held between the spouses, with each disclaiming beneficial ownership beyond their pecuniary interest.

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Insider Blume-Jensen Peter, Masson Kristina
Role President and CEO | EVP - Business Operations
Type Security Shares Price Value
Tax Withholding Common Stock 13,729 $1.79 $25K
holding Common Stock -- -- --
Holdings After Transaction: Common Stock — 2,245,317 shares (Direct, null); Common Stock — 386,343 shares (Indirect, See Footnote)
Footnotes (1)
  1. Shares withheld by the Issuer to satisfy the mandatory tax withholding requirement upon vesting of restricted stock units. 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. 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.
Tax-withheld shares 13,729 shares Shares withheld to satisfy mandatory tax withholding on RSU vesting
Tax-withholding price $1.79 per share Price used for the 13,729 tax-withheld common shares
Direct CEO holdings after transaction 2,245,317 shares Common stock directly held by Dr. Peter Blume-Jensen following disposition
Indirectly held common stock 386,343 shares Indirect holdings between Dr. Blume-Jensen and Dr. Masson with pecuniary-interest disclaimers
restricted stock units financial
"Shares withheld by the Issuer to satisfy the 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.
mandatory tax withholding requirement financial
"Shares withheld by the Issuer to satisfy the mandatory tax withholding requirement upon vesting of restricted stock units."
beneficial ownership financial
"Dr. Masson disclaims beneficial ownership of such securities except to the extent of her pecuniary interest therein."
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.
pecuniary interest financial
"Dr. Blume-Jensen disclaims beneficial ownership of such securities except to the extent of his pecuniary interest therein."
Form 4 Insider Transactions: What Each Field Means →
SEC Form 4
FORM 4UNITED 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)
XDirector10% Owner
XOfficer (give title below)Other (specify below)
President and CEO
2a. Foreign Trading Symbol
3. Date of Earliest Transaction (Month/Day/Year)
05/21/2026		6. Individual or Joint/Group Filing (Check Applicable Line)
Form filed by One Reporting Person
XForm 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)
CodeVAmount(A) or (D)Price
Common Stock05/21/2026F(1)13,729D$1.792,245,317D(2)
Common Stock386,343ISee 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)
CodeV(A)(D)Date ExercisableExpiration DateTitleAmount 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
XDirector10% Owner
XOfficer (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
XDirector10% Owner
XOfficer (give title below)Other (specify below)
EVP - Business Operations
Explanation of Responses:
1. Shares withheld by the Issuer 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-Jensen05/26/2026
/s/ Adam D. Levy, Attorney-in-Fact for Kristina Masson05/26/2026
** Signature of Reporting PersonDate
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)

Source: View Original Filing on SEC EDGAR

FAQ

What insider transaction did Acrivon Therapeutics (ACRV) report in this Form 4?

Acrivon reported a tax-related insider transaction where 13,729 shares of common stock were withheld to cover mandatory tax obligations upon RSU vesting. This is a non-market tax-withholding disposition, not an open-market purchase or sale of shares by the insiders.

How many Acrivon (ACRV) shares were withheld for taxes in the filing?

The filing shows 13,729 shares of Acrivon common stock withheld at $1.79 per share. These shares were used to satisfy mandatory tax withholding obligations triggered when restricted stock units vested for the reporting insider, rather than being sold into the open market.

How many Acrivon (ACRV) shares does the CEO hold after this Form 4 event?

After the reported tax-withholding disposition, President and CEO Dr. Peter Blume-Jensen directly holds 2,245,317 shares of Acrivon common stock. The Form 4 also notes additional indirectly held shares between the spouses, with each spouse disclaiming beneficial ownership beyond their pecuniary interest.

Is the Acrivon (ACRV) Form 4 transaction an open-market sale by insiders?

No, the transaction is not an open-market sale. The 13,729 shares of common stock were withheld by Acrivon to meet mandatory tax obligations when restricted stock units vested, which is recorded as a tax-withholding disposition rather than a discretionary sale into the market by the insiders.

What indirect Acrivon (ACRV) share holdings are disclosed for the insiders?

The Form 4 discloses 386,343 shares of Acrivon common stock as indirectly held between President and CEO Dr. Peter Blume-Jensen and EVP Dr. Kristina Masson. Each spouse disclaims beneficial ownership of the other’s holdings except to the extent of their pecuniary interest in those securities.

What is the role of restricted stock units (RSUs) in this Acrivon (ACRV) filing?

The filing explains that the share disposition arose from RSUs vesting for an insider. When these restricted stock units vested, Acrivon withheld 13,729 shares of common stock to satisfy mandatory tax withholding requirements, creating the reported tax-withholding disposition rather than a market trade.