Werewolf Therapeutics (HOWL) director-linked funds disclose stock sales

Rhea-AI Filing Summary

Werewolf Therapeutics director Luke Evnin reported indirect sales of the company’s common stock by affiliated investment entities, executed under a Rule 10b5-1 trading plan dated September 24, 2025. On January 8, 2026, these entities sold 7,716 shares at a weighted-average price of $0.63, on January 9 they sold 24,678 shares at a weighted-average price of $0.61, and on January 12 they sold 58,980 shares at a weighted-average price of $0.57, each across multiple trades within stated price ranges.

After these transactions, the affiliated entities collectively held 2,309,869 shares of Werewolf Therapeutics common stock indirectly. The shares are spread across several MPM-managed entities, and Evnin disclaims beneficial ownership of the securities except to the extent of 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)
01/08/2026

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	01/08/2026		S(1)		7,716(2)	D	$0.63(3)	2,393,527	I	See Footnotes(4)(5)
Common Stock	01/09/2026		S(1)		24,678(6)	D	$0.61(7)	2,368,849	I	See Footnotes(4)(8)
Common Stock	01/12/2026		S(1)		58,980(9)	D	$0.57(10)	2,309,869	I	See Footnotes(4)(11)

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: 825 by MPM Asset Management LLC ("AM LLC"), 5,215 by MPM BioVentures 2014, L.P. ("BV 2014"), 348 by MPM BioVentures 2014(B), L.P. ("BV 2014(B)"), 180 by MPM Asset Management Investors BV2014 LLC ("AM BV2014") and 1,148 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 $0.6243 to $0.6368 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: 256,407 by AM LLC, 1,618,978 by BV 2014, 107,983 by BV 2014(B), 55,720 by AM BV2014 and 354,439 by MPM OIF.

6. The shares were sold as follows: 2,640 by AM LLC, 16,678 by BV 2014, 1,112 by BV 2014(B), 575 by AM BV2014 and 3,673 by MPM OIF.

7. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $0.6019 to $0.6583 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.

8. The shares are held as follows: 253,767 by AM LLC, 1,602,300 by BV 2014, 106,871 by BV 2014(B), 55,145 by AM BV2014 and 350,766 by MPM OIF.

9. The shares were sold as follows: 6,309 by AM LLC, 39,861 by BV 2014, 2,659 by BV 2014(B), 1,373 by AM BV2014 and 8,778 by MPM OIF.

10. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $0.5608 to $0.606 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.

11. The shares are held as follows: 247,458 by AM LLC, 1,562,439 by BV 2014, 104,212 by BV 2014(B), 53,772 by AM BV2014 and 341,988 by MPM OIF.

	/s/ Luke Evnin	01/12/2026
	** 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).
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FAQ

What insider stock activity did Werewolf Therapeutics (HOWL) disclose in this Form 4?

The Form 4 reports that investment entities affiliated with director Luke Evnin sold Werewolf Therapeutics common stock in three transactions on January 8, 9 and 12, 2026, totaling tens of thousands of shares at weighted-average prices between $0.57 and $0.63.

Were the HOWL insider sales made under a Rule 10b5-1 trading plan?

Yes. A footnote states the transactions were effected pursuant to a Rule 10b5-1 plan dated September 24, 2025, which is a pre-arranged trading plan for buying or selling securities.

Who actually sold the Werewolf Therapeutics shares reported for Luke Evnin?

The shares were sold by several MPM-managed 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. Evnin is associated with these entities and reports the transactions but disclaims beneficial ownership except for his pecuniary interest.

How many HOWL shares remain held by the affiliated entities after these sales?

Following the January 12, 2026 transaction, the affiliated entities collectively held 2,309,869 shares of Werewolf Therapeutics common stock indirectly.

What prices were received for the HOWL shares sold in these transactions?

The weighted-average prices were $0.63 for 7,716 shares on January 8, $0.61 for 24,678 shares on January 9, and $0.57 for 58,980 shares on January 12, 2026. Each price reflects multiple trades within disclosed price ranges.

What is Luke Evnin’s relationship to Werewolf Therapeutics and these entities?

Luke Evnin is a director of Werewolf Therapeutics and a member or manager of several MPM investment entities that hold the shares. A footnote states he disclaims beneficial ownership of the securities except to the extent of his pecuniary interest.