HOWL 10% holder files Form 4 for planned Rule 10b5‑1 sales

Rhea-AI Filing Summary

Werewolf Therapeutics (HOWL): A director and 10% owner affiliated with MPM entities reported open‑market sales totaling 213,529 shares across 11/07–11/12/2025 under a Rule 10b5‑1 plan dated September 24, 2025. Weighted average prices by day were $1.11, $1.18, $1.14 and $1.09, with disclosed trade ranges spanning $1.065 to $1.21. Following these transactions, indirect beneficial ownership was 5,691,191 shares.

Insights

Equity ownership and insider activity analyst

Planned sales by a 10% holder totaled 213,529 shares at ~$1.07–$1.21.

The filing shows a director/10% owner group executed open‑market sales on 11/07/2025, 11/10/2025, 11/11/2025 and 11/12/2025 under a Rule 10b5‑1 plan dated September 24, 2025. Daily weighted average prices were $1.11, $1.18, $1.14, and $1.09.

Sales aggregated to 213,529 shares, with reported execution ranges from $1.065 to $1.21. Ownership remains indirect across multiple MPM-related funds, with 5,691,191 shares beneficially owned after the last transaction.

Because transactions were made pursuant to a pre‑set 10b5‑1 plan, signaling value is limited; effects depend on future disclosures and holder decisions.

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^*

GADICKE ANSBERT

(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^*

GADICKE ANSBERT

(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 ONCOLOGY INNOVATIONS FUND LP

(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^*

UBS Oncology Impact Fund 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^*

Oncology Impact Fund (Cayman) Management 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 BioImpact 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 Oncology Innovations Fund 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 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 MPM BioVentures 2014, L.P.

	/s/ Ansbert Gadicke, Manager of MPM Oncology Innovations Fund GP LLC, the GP of MPM Oncology Innovations Fund, L.P.	11/12/2025
	/s/ Ansbert Gadicke, Manager of MPM Oncology Innovations Fund GP LLC	11/12/2025
	/s/ Ansbert Gadicke, Managing Partner of MPM BioImpact LLC	11/12/2025
	/s/ Ansbert Gadicke, member of MPM Asset Management LLC	11/12/2025
	/s/ Ansbert Gadicke	11/12/2025
	/s/ Ansbert Gadicke, Managing Partner of MPM BioImpact LLC, the GP of Oncology Impact Fund (Cayman) Management L.P., the GP of UBS Oncology Impact Fund, L.P.	11/12/2025
	/s/ Ansbert Gadicke, Managing Partner of MPM BioImpact LLC, the GP of Oncology Impact Fund (Cayman) Management L.P.	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.
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FAQ

What did HOWL’s insider report selling on the Form 4?

Open‑market sales totaling 213,529 shares across 11/07–11/12/2025.

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

Yes. The transactions were effected under a Rule 10b5‑1 plan dated September 24, 2025.

What prices were disclosed for the HOWL insider sales?

Daily weighted averages were $1.11, $1.18, $1.14, $1.09, with execution ranges from $1.065 to $1.21.

How many HOWL shares were beneficially owned after these sales?

Indirect beneficial ownership was 5,691,191 shares following the 11/12/2025 transactions.

Who are the reporting persons associated with the HOWL Form 4?

MPM-affiliated entities and related funds, with roles including director and 10% owner.

Was ownership reported as direct or indirect?

The filing lists indirect ownership through multiple MPM-related entities and funds.