Werewolf Therapeutics insider sells 242,890 shares via 10b5-1

Rhea-AI Filing Summary

Werewolf Therapeutics (HOWL): Insider transactions disclosed. An affiliated group led by MPM BioImpact reported open‑market sales of common stock on three dates under a Rule 10b5‑1 plan dated September 24, 2025.

Across 11/04/2025, 11/05/2025, and 11/06/2025, the group sold a combined 242,890 shares, at weighted‑average prices of $1.22, $1.22, and $1.21, respectively. Reported price ranges were $1.17–$1.30, $1.19–$1.25, and $1.185–$1.27. Following these transactions, the reporting persons indirectly beneficially owned 5,904,720 shares.

The filing notes the reporting person is a director and 10% owner, and that sales were allocated among affiliated entities including 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.

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)
11/04/2025

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	11/04/2025		S(1)		140,488(2)(3)	D	$1.22(4)	6,007,122	I	See Footnote(5)
Common Stock	11/05/2025		S(1)		47,950(6)	D	$1.22(7)	5,959,172	I	See Footnote(8)
Common Stock	11/06/2025		S(1)		54,452(9)	D	$1.21(10)	5,904,720	I	See Footnote(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

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: 9,645 by MPM Asset Management LLC ("AM LLC"), 60,937 by MPM BioVentures 2014, L.P. ("BV 2014"), 4,064 by MPM BioVentures 2014(B), L.P. (BV 2014(B), 2,098 by MPM Asset Management Investors BV2014 LLC ("AM BV2014"), 13,420 by MPM Oncology Innovations Fund, L.P. ("MPM OIF") and 50,324 by UBS Oncology Impact Fund L.P. ("UBS Oncology"). 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. Ansbert Gadicke is a member of AM LLC, a managing director of BV LLC and a manager of MPM OIF GP. Each Reporting Person disclaims beneficial ownership of the securities except to the extent of his or its pecuniary interest therein.

3. 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 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.

4. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $1.17 to $1.30 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.

5. The shares are held as follows: 412,556 by AM LLC, 2,605,487 by BV 2014, 173,782 by BV 2014(B), 89,680 by AM BV2014, 571,690 by MPM OIF and 2,153,927 by UBS Oncology.

6. The shares were sold as follows: 3,292 by AM LLC, 20,798 by BV 2014, 1,387 by BV 2014(B), 717 by AM BV2014, 4,580 by MPM OIF and 17,176 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 $1.19 to $1.25 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: 409,264 by AM LLC, 2,584,689 by BV 2014, 172,395 by BV 2014(B), 88,963 by AM BV2014, 567,110 by MPM OIF and 2,136,751 by UBS Oncology.

9. The shares were sold as follows: 3,738 by AM LLC, 23,619 by BV 2014, 1,575 by BV 2014(B), 814 by AM BV2014, 5,201 by MPM OIF and 19,505 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 $1.185 to $1.27 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: 405,526 by AM LLC, 2,561,070 by BV 2014, 170,820 by BV 2014(B), 88,149 by AM BV2014, 561,909 by MPM OIF and 2,117,246 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	11/06/2025
	/s/ Ansbert Gadicke, Managing Director of MPM BioVentures 2014 LLC, the manager of MPM Asset Management Investors BV2014 LLC	11/06/2025
	/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.	11/06/2025
	/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.	11/06/2025
	/s/ Ansbert Gadicke, Managing Director of MPM BioVentures 2014 LLC, the Managing Member of MPM BioVentures 2014 GP LLC	11/06/2025
	** Signature of Reporting Person	Date
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FAQ

How many HOWL shares were sold in this Form 4?

A total of 242,890 shares of common stock were sold across three transactions.

On what dates did the HOWL insider sales occur?

Sales occurred on 11/04/2025, 11/05/2025, and 11/06/2025.

What prices were reported for the HOWL share sales?

Weighted averages were $1.22, $1.22, and $1.21, with ranges of $1.17–$1.30, $1.19–$1.25, and $1.185–$1.27.

Was there a Rule 10b5-1 plan for these HOWL transactions?

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

How many HOWL shares were beneficially owned after the reported sales?

Following the transactions, the reporting persons indirectly beneficially owned 5,904,720 shares.

What is the relationship of the reporting person to Werewolf Therapeutics (HOWL)?

The reporting person is disclosed as a director and 10% owner.

Which affiliated entities sold the HOWL shares?

Entities listed include 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..