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Werewolf Therapeutics, Inc. (HOWL) director discloses Rule 10b5-1 stock sales

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

Rhea-AI Filing Summary

Werewolf Therapeutics director Luke Evnin reported insider sales of the company’s common stock in mid-December 2025. On December 10, he reported selling 37,104 shares at a weighted average price of $1.06 per share through MPM-affiliated investment entities. On December 11 and 12, he reported additional sales of 28,009 and 17,858 shares at weighted average prices of $1.07 and $1.08, respectively, each executed in multiple trades within disclosed price ranges. These transactions were carried out under a Rule 10b5-1 trading plan dated September 24, 2025, and after the reported sales he indicated indirect beneficial ownership of 2,890,128 shares held across several MPM-managed funds.

Positive

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Insider EVNIN LUKE
Role Director
Sold 82,971 shs ($89K)
Type Security Shares Price Value
Sale Common Stock 17,858 $1.08 $19K
Sale Common Stock 28,009 $1.07 $30K
Sale Common Stock 37,104 $1.06 $39K
Holdings After Transaction: Common Stock — 2,890,128 shares (Indirect, See Footnotes)
Footnotes (1)
  1. Transaction effected pursuant to a plan established pursuant to Rule 10b5-1 dated September 24, 2025. The shares were sold as follows: 3,969 by MPM Asset Management LLC ("AM LLC"), 25,077 by MPM BioVentures 2014, L.P. ("BV 2014"), 1,673 by MPM BioVentures 2014(B), L.P. ("BV 2014(B)"), 863 by MPM Asset Management Investors BV2014 LLC ("AM BV2014") and 5,522 by MPM Oncology Innovations Fund, L.P. ("MPM OIF"). The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $0.9742 to $1.11 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. 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. The shares are held as follows: 314,437 by AM LLC, 1,985,601 by BV 2014, 132,436 by BV 2014(B), 68,344 by AM BV2014 and 435,177 by MPM OIF. The shares were sold as follows: 2,996 by AM LLC, 18,930 by BV 2014, 1,263 by BV 2014(B), 651 by AM BV2014 and 4,169 by MPM OIF. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $1.045 to $1.10 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. The shares are held as follows: 311,441 by AM LLC, 1,966,671 by BV 2014, 131,173 by BV 2014(B), 67,693 by AM BV2014 and 431,008 by MPM OIF. The shares were sold as follows: 1,910 by AM LLC, 12,069 by BV 2014, 805 by BV 2014(B), 416 by AM BV2014 and 2,658 by MPM OIF. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $1.06 to $1.10 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. The shares are held as follows: 309,531 by AM LLC, 1,954,602 by BV 2014, 130,368 by BV 2014(B),67,277 by AM BV2014 and 428,350 by MPM OIF.
Form 4 Insider Transactions: What Each Field Means →
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).
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)
12/10/2025
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 12/10/2025 S(1) 37,104(2) D $1.06(3) 2,935,995 I See Footnotes(4)(5)
Common Stock 12/11/2025 S(1) 28,009(6) D $1.07(7) 2,907,986 I See Footnotes(4)(8)
Common Stock 12/12/2025 S(1) 17,858(9) D $1.08(10) 2,890,128 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: 3,969 by MPM Asset Management LLC ("AM LLC"), 25,077 by MPM BioVentures 2014, L.P. ("BV 2014"), 1,673 by MPM BioVentures 2014(B), L.P. ("BV 2014(B)"), 863 by MPM Asset Management Investors BV2014 LLC ("AM BV2014") and 5,522 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 $0.9742 to $1.11 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: 314,437 by AM LLC, 1,985,601 by BV 2014, 132,436 by BV 2014(B), 68,344 by AM BV2014 and 435,177 by MPM OIF.
6. The shares were sold as follows: 2,996 by AM LLC, 18,930 by BV 2014, 1,263 by BV 2014(B), 651 by AM BV2014 and 4,169 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 $1.045 to $1.10 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: 311,441 by AM LLC, 1,966,671 by BV 2014, 131,173 by BV 2014(B), 67,693 by AM BV2014 and 431,008 by MPM OIF.
9. The shares were sold as follows: 1,910 by AM LLC, 12,069 by BV 2014, 805 by BV 2014(B), 416 by AM BV2014 and 2,658 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 $1.06 to $1.10 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: 309,531 by AM LLC, 1,954,602 by BV 2014, 130,368 by BV 2014(B),67,277 by AM BV2014 and 428,350 by MPM OIF.
/s/ Luke Evnin 12/12/2025
** 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.

Source: View Original Filing on SEC EDGAR

FAQ

What insider transaction did Werewolf Therapeutics (HOWL) disclose?

Werewolf Therapeutics disclosed that director Luke Evnin filed a Form 4 reporting sales of the company’s common stock over three days in December 2025.

How many Werewolf Therapeutics shares did Luke Evnin sell and on which dates?

He reported selling 37,104 shares on December 10, 28,009 shares on December 11, and 17,858 shares on December 12, 2025, all in Werewolf Therapeutics common stock.

At what prices were the HOWL shares sold by Luke Evnin?

The reported weighted average sale prices were $1.06 per share on December 10, $1.07 on December 11, and $1.08 on December 12, with each day’s sales executed across price ranges disclosed in the filing.

Were Luke Evnin’s HOWL stock sales made under a Rule 10b5-1 trading plan?

Yes. The filing states that the transactions were effected pursuant to a Rule 10b5-1 trading plan that was established on September 24, 2025.

How many Werewolf Therapeutics shares does Luke Evnin report owning after these transactions?

After the reported sales, he reported 2,890,128 shares of indirect beneficial ownership in Werewolf Therapeutics common stock through various MPM-affiliated investment funds.

How are Luke Evnin’s remaining HOWL shares held across MPM entities?

The remaining shares are reported as being held by several MPM-related entities, including AM LLC, MPM BioVentures 2014, MPM BioVentures 2014(B), AM BV2014, and MPM Oncology Innovations Fund, each holding a portion of the total 2,890,128 shares.