MPM funds trim Werewolf Therapeutics (HOWL) stake via 10b5-1 plan

Rhea-AI Filing Summary

Werewolf Therapeutics director–affiliated funds reported a small share sale. On January 16, 2026, investment entities associated with director Luke Evnin sold a total of 38,782 shares of Werewolf Therapeutics, Inc. common stock under a pre‑established Rule 10b5-1 trading plan dated September 24, 2025.

The weighted average sale price was $0.54 per share, with individual trades executed between $0.535 and $0.5495. The shares were sold by several MPM-managed entities, including AM LLC, MPM BioVentures 2014 funds, AM BV2014 and MPM Oncology Innovations Fund. After these transactions, entities associated with Evnin indirectly held 2,159,860 shares of Werewolf Therapeutics across these vehicles, and he disclaims beneficial ownership beyond his pecuniary interest.

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

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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

X

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^*

EVNIN LUKE

(Last) (First) (Middle)

C/O MPM BIOIMPACT LLC

399 BOYLSTON STREET, SUITE 1100

(Street)

BOSTON MA 02116

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Werewolf Therapeutics, Inc. [ HOWL ]

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

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

3. Date of Earliest Transaction (Month/Day/Year)
01/16/2026

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)
			Code	V	Amount	(A) or (D)	Price
Common Stock	01/16/2026		S(1)		38,782(2)	D	$0.54(3)	2,159,860	I	See Footnotes(4)(5)

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. Transaction effected pursuant to a plan established pursuant to Rule 10b5-1 dated September 24, 2025.

2. The shares were sold as follows: 4,152 by MPM Asset Management LLC ("AM LLC"), 26,213 by MPM BioVentures 2014, L.P. ("BV 2014"), 1,749 by MPM BioVentures 2014(B), L.P. ("BV 2014(B)"), 893 by MPM Asset Management Investors BV2014 LLC ("AM BV2014") and 5,775 by MPM Oncology Innovations Fund, L.P. ("MPM OIF").

3. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $0.535 to $0.5495 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.

4. MPM BioVentures 2014 GP LLC and MPM BioVentures 2014 LLC ("BV LLC") are the direct and indirect general partners of BV 2014 and BV 2014(B). BV LLC is the manager of AM BV2014. MPM Oncology Innovations Fund GP LLC ("MPM OIF GP") is the general partner of MPM OIF. Luke Evnin is a member of AM LLC, a Managing Director of BV LLC and a manager of MPM OIF GP. The Reporting Person disclaims beneficial ownership of the securities except to the extent of his pecuniary interest therein.

5. The shares are held as follows: 231,408 by AM LLC, 1,461,054 by BV 2014, 97,450 by BV 2014(B), 50,289 by AM BV2014 and 319,659 by MPM OIF.

	/s/ Luke Evnin	01/20/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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FAQ

What insider transaction did Werewolf Therapeutics (HOWL) report for January 16, 2026?

Investment entities associated with director Luke Evnin reported selling a total of 38,782 shares of Werewolf Therapeutics, Inc. common stock on January 16, 2026.

Who actually sold the Werewolf Therapeutics (HOWL) shares in this Form 4 filing?

The shares were sold by MPM-related entities, including MPM Asset Management LLC, MPM BioVentures 2014, L.P., MPM BioVentures 2014(B), L.P., MPM Asset Management Investors BV2014 LLC and MPM Oncology Innovations Fund, L.P., rather than directly by Luke Evnin.

At what price were the Werewolf Therapeutics (HOWL) shares sold in this insider transaction?

The reported weighted average sale price was $0.54 per share, with individual trades executed at prices ranging from $0.535 to $0.5495 per share.

How many Werewolf Therapeutics (HOWL) shares remain indirectly held after this sale?

After the reported sale, entities associated with Luke Evnin indirectly held 2,159,860 shares of Werewolf Therapeutics common stock, spread across several MPM-managed entities.

Was the Werewolf Therapeutics (HOWL) insider sale made under a Rule 10b5-1 plan?

Yes. The filing states that the transaction was effected under a Rule 10b5-1 trading plan that was established on September 24, 2025.

How are the remaining Werewolf Therapeutics (HOWL) shares allocated among the MPM entities?

The remaining shares are held as follows: 231,408 by AM LLC, 1,461,054 by MPM BioVentures 2014, L.P., 97,450 by MPM BioVentures 2014(B), L.P., 50,289 by AM BV2014 and 319,659 by MPM Oncology Innovations Fund, L.P.

Does Luke Evnin claim full beneficial ownership of the Werewolf Therapeutics (HOWL) shares in this filing?

No. The filing notes that Luke Evnin disclaims beneficial ownership of the reported securities except to the extent of his pecuniary interest in the MPM entities that hold the shares.