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

HOWL insider sales: 213,529 shares; holdings now 5,691,191

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

Rhea-AI Filing Summary

Werewolf Therapeutics (HOWL): affiliated reporting persons led by MPM entities, identified as a director and 10% owner, reported open‑market sales executed under a Rule 10b5‑1 plan dated September 24, 2025. Sales occurred on November 7–12, 2025 across four days totaling 213,529 shares.

Disclosed transactions: 68,480 shares on 11/07 at a weighted average price of $1.11; 48,570 on 11/10 at $1.18; 55,810 on 11/11 at $1.14; and 40,669 on 11/12 at $1.09. Following these trades, the group reported 5,691,191 shares beneficially owned, held indirectly across multiple MPM-managed entities. Price ranges for the weighted averages were provided for each day, and the filing notes it is one of two identical filings due to reporting person limits.

Positive

  • None.

Negative

  • None.
Insider MPM BioVentures 2014, L.P., MPM BioVentures 2014 (B), L.P., MPM BioVentures 2014 LLC, MPM BioVentures 2014 GP LLC, MPM Asset Management Investors BV2014 LLC
Role 10% Owner | 10% Owner | 10% Owner | 10% Owner | 10% Owner
Sold 213,529 shs ($241K)
Type Security Shares Price Value
Sale Common Stock 40,669 $1.09 $44K
Sale Common Stock 55,810 $1.14 $64K
Sale Common Stock 48,570 $1.18 $57K
Sale Common Stock 68,480 $1.11 $76K
Holdings After Transaction: Common Stock — 5,691,191 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: 4,702 by MPM Asset Management LLC ("AM LLC"), 29,704 by MPM BioVentures 2014, L.P. ("BV 2014"), 1,981 by MPM BioVentures 2014(B), L.P. ("BV 2014(B)"), 1,022 by MPM Asset Management Investors BV2014 LLC ("AM BV2014"), 6,541 by MPM Oncology Innovations Fund, L.P. ("MPM OIF") and 24,530 by UBS Oncology Impact Fund L.P. ("UBS Oncology"). The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $1.075 to $1.188 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. MPM BioImpact LLC ("BioImpact") is the General Partner of Oncology Impact Fund (Cayman) Management L.P., the General Partner of UBS Oncology. Ansbert Gadicke is a member of AM LLC, a managing director of BV LLC, a manager of MPM OIF GP and the managing partner of BioImpact. Each Reporting Person disclaims beneficial ownership of the securities except to the extent of his or its pecuniary interest therein. The shares are held as follows: 400,824 by AM LLC, 2,531,366 by BV 2014, 168,839 by BV 2014(B), 87,127 by AM BV2014, 555,368 by MPM OIF and 2,092,716 by UBS Oncology. The shares were sold as follows: 3,335 by AM LLC, 21,067 by BV 2014, 1,405 by BV 2014(B), 725 by AM BV2014, 4,640 by MPM OIF and 17,398 by UBS Oncology. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $1.145 to $1.21 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: 397,489 by AM LLC, 2,510,299 by BV 2014, 167,434 by BV 2014(B), 86,402 by AM BV2014, 550,728 by MPM OIF and 2,075,318 by UBS Oncology. The shares were sold as follows: 3,832 by AM LLC, 24,208 by BV 2014, 1,615 by BV 2014(B), 832 by AM BV2014, 5,331 by MPM OIF and 19,992 by UBS Oncology. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $1.115 to $1.17 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: 393,657 by AM LLC, 2,486,091 by BV 2014, 165,819 by BV 2014(B), 85,570 by AM BV2014, 545,397 by MPM OIF and 2,055,326 by UBS Oncology. The shares were sold as follows: 2,792 by AM LLC, 17,640 by BV 2014, 1,177 by BV 2014(B), 607 by AM BV2014, 3,885 by MPM OIF and 14,568 by UBS Oncology. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $1.065 to $1.145 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: 390,865 by AM LLC, 2,468,451 by BV 2014, 164,642 by BV 2014(B), 84,963 by AM BV2014, 541,512 by MPM OIF and 2,040,758 by UBS Oncology.
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*
MPM BioVentures 2014, L.P.
(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)
Director X 10% Owner
Officer (give title below) Other (specify below)
3. Date of Earliest Transaction (Month/Day/Year)
11/07/2025
4. If Amendment, Date of Original Filed (Month/Day/Year)
 6. Individual or Joint/Group Filing (Check Applicable Line)
Form filed by One Reporting Person
X 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 11/07/2025 S(1) 68,480(2) D $1.11(3) 5,836,240 I See Footnotes(4)(5)
Common Stock 11/10/2025 S(1) 48,570(6) D $1.18(7) 5,787,670 I See Footnotes(4)(8)
Common Stock 11/11/2025 S(1) 55,810(9) D $1.14(10) 5,731,860 I See Footnotes(4)(11)
Common Stock 11/12/2025 S(1) 40,669(12) D $1.09(13) 5,691,191 I See Footnotes(4)(14)
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*
MPM BioVentures 2014, L.P.
(Last) (First) (Middle)
C/O MPM BIOIMPACT LLC
399 BOYLSTON STREET, SUITE 1100
(Street)
BOSTON MA 02116
(City) (State) (Zip)
Relationship of Reporting Person(s) to Issuer
Director X 10% Owner
Officer (give title below) Other (specify below)
1. Name and Address of Reporting Person*
MPM BioVentures 2014 (B), L.P.
(Last) (First) (Middle)
C/O MPM BIOIMPACT
399 BOYLSTON STREET, SUITE 1100
(Street)
BOSTON MA 02116
(City) (State) (Zip)
Relationship of Reporting Person(s) to Issuer
Director X 10% Owner
Officer (give title below) Other (specify below)
1. Name and Address of Reporting Person*
MPM BioVentures 2014 LLC
(Last) (First) (Middle)
C/O MPM BIOIMPACT LLC
399 BOYLSTON STREET, SUITE 1100
(Street)
BOSTON MA 02116
(City) (State) (Zip)
Relationship of Reporting Person(s) to Issuer
Director X 10% Owner
Officer (give title below) Other (specify below)
1. Name and Address of Reporting Person*
MPM BioVentures 2014 GP LLC
(Last) (First) (Middle)
C/O MPM BIOIMPACT LLC
399 BOYLSTON STREET, SUITE 1100
(Street)
BOSTON MA 02116
(City) (State) (Zip)
Relationship of Reporting Person(s) to Issuer
Director X 10% Owner
Officer (give title below) Other (specify below)
1. Name and Address of Reporting Person*
MPM Asset Management Investors BV2014 LLC
(Last) (First) (Middle)
C/O MPM BIOIMPACT LLC
399 BOYLSTON STREET, SUITE 1100
(Street)
BOSTON MA 02116
(City) (State) (Zip)
Relationship of Reporting Person(s) to Issuer
Director X 10% Owner
Officer (give title below) Other (specify below)
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: 4,702 by MPM Asset Management LLC ("AM LLC"), 29,704 by MPM BioVentures 2014, L.P. ("BV 2014"), 1,981 by MPM BioVentures 2014(B), L.P. ("BV 2014(B)"), 1,022 by MPM Asset Management Investors BV2014 LLC ("AM BV2014"), 6,541 by MPM Oncology Innovations Fund, L.P. ("MPM OIF") and 24,530 by UBS Oncology Impact Fund L.P. ("UBS Oncology").
3. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $1.075 to $1.188 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. MPM BioImpact LLC ("BioImpact") is the General Partner of Oncology Impact Fund (Cayman) Management L.P., the General Partner of UBS Oncology. Ansbert Gadicke is a member of AM LLC, a managing director of BV LLC, a manager of MPM OIF GP and the managing partner of BioImpact. Each Reporting Person disclaims beneficial ownership of the securities except to the extent of his or its pecuniary interest therein.
5. The shares are held as follows: 400,824 by AM LLC, 2,531,366 by BV 2014, 168,839 by BV 2014(B), 87,127 by AM BV2014, 555,368 by MPM OIF and 2,092,716 by UBS Oncology.
6. The shares were sold as follows: 3,335 by AM LLC, 21,067 by BV 2014, 1,405 by BV 2014(B), 725 by AM BV2014, 4,640 by MPM OIF and 17,398 by UBS Oncology.
7. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $1.145 to $1.21 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: 397,489 by AM LLC, 2,510,299 by BV 2014, 167,434 by BV 2014(B), 86,402 by AM BV2014, 550,728 by MPM OIF and 2,075,318 by UBS Oncology.
9. The shares were sold as follows: 3,832 by AM LLC, 24,208 by BV 2014, 1,615 by BV 2014(B), 832 by AM BV2014, 5,331 by MPM OIF and 19,992 by UBS Oncology.
10. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $1.115 to $1.17 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: 393,657 by AM LLC, 2,486,091 by BV 2014, 165,819 by BV 2014(B), 85,570 by AM BV2014, 545,397 by MPM OIF and 2,055,326 by UBS Oncology.
12. The shares were sold as follows: 2,792 by AM LLC, 17,640 by BV 2014, 1,177 by BV 2014(B), 607 by AM BV2014, 3,885 by MPM OIF and 14,568 by UBS Oncology.
13. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $1.065 to $1.145 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.
14. The shares are held as follows: 390,865 by AM LLC, 2,468,451 by BV 2014, 164,642 by BV 2014(B), 84,963 by AM BV2014, 541,512 by MPM OIF and 2,040,758 by UBS Oncology.
Remarks:
This filing is 1 of 2 identical filings due to limitations on number of Reporting Persons. See Form 4 filed by Ansbert Gadicke.
/s/ Ansbert Gadicke, Managing Director of MPM BioVentures 2014 LLC 11/12/2025
/s/ Ansbert Gadicke, Managing Director of MPM BioVentures 2014 LLC, the manager of MPM Asset Management Investors BV2014 LLC 11/12/2025
/s/ Ansbert Gadicke, Managing Director of MPM BioVentures 2014 LLC, the Managing Member of MPM BioVentures 2014 GP LLC, the GP of MPM BioVentures 2014 (B), L.P. 11/12/2025
/s/ Ansbert Gadicke, Managing Director of MPM BioVentures 2014 LLC, the Managing Member of MPM BioVentures 2014 GP LLC, the GP of MPM BioVentures 2014, L.P. 11/12/2025
/s/ Ansbert Gadicke, Managing Director of MPM BioVentures 2014 LLC, the Managing Member of MPM BioVentures 2014 GP LLC 11/12/2025
** 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 activity did HOWL report?

Affiliated reporting persons (director and 10% owner) sold shares in open-market transactions under a Rule 10b5-1 plan dated September 24, 2025.

How many HOWL shares were sold and on which dates?

213,529 shares across four days: 68,480 (11/07), 48,570 (11/10), 55,810 (11/11), and 40,669 (11/12).

What prices did the HOWL shares sell for?

Weighted average prices were $1.11 (11/07), $1.18 (11/10), $1.14 (11/11), and $1.09 (11/12), with disclosed daily price ranges.

How many HOWL shares were beneficially owned after the sales?

5,691,191 shares beneficially owned following the transactions, held indirectly across multiple MPM-managed entities.

Was the selling under a pre-arranged plan?

Yes. The filing states the transactions were effected pursuant to a Rule 10b5-1 plan dated September 24, 2025.

Who are the selling entities associated with the HOWL shares?

Holdings are spread among MPM Asset Management LLC, MPM BioVentures 2014, L.P., MPM BioVentures 2014(B), L.P., MPM Asset Management Investors BV2014 LLC, MPM Oncology Innovations Fund, L.P., and UBS Oncology Impact Fund L.P.