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

Rhea-AI Filing Summary

Werewolf Therapeutics (HOWL): insider sales reported by MPM-affiliated holders. Reporting persons associated with MPM BioImpact/MPM BioVentures, identified as a Director and 10% Owner, disclosed open‑market sales executed pursuant to a Rule 10b5‑1 plan dated September 24, 2025.

Sales occurred on three dates: 72,709 shares on 10/27/2025 at a weighted average price of $1.72 (individual trades ranged $1.675–$1.82); 69,068 shares on 10/28/2025 at a weighted average price of $1.64 (range $1.605–$1.70); and 134,240 shares on 10/29/2025 at a weighted average price of $1.55 (range $1.51–$1.62).

Following these transactions, the reporting group’s beneficial ownership (indirect) was 6,645,961 shares after 10/27, 6,576,893 shares after 10/28, and 6,442,653 shares after 10/29, held across affiliated funds as detailed in the footnotes.

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)
10/27/2025

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	10/27/2025		S(1)		72,709(2)(3)	D	$1.72(4)	6,645,961	I	See Footnote(5)
Common Stock	10/28/2025		S(1)		69,068(6)	D	$1.64(7)	6,576,893	I	See Footnote(8)
Common Stock	10/29/2025		S(1)		134,240(9)	D	$1.55(10)	6,442,653	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: 4,992 by MPM Asset Management LLC ("AM LLC"), 31,538 by MPM BioVentures 2014, L.P. ("BV 2014"), 2,104 by MPM BioVentures 2014(B), L.P. (BV 2014(B), 1,085 MPM Asset Management Investors BV2014 LLC ("AM BV2014"), 6,945 by MPM Oncology Innovations Fund, L.P. ("MPM OIF") and 26,045 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 $1.675 to $1.82 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: 456,416 by AM LLC, 2,882,585 by BV 2014, 192,263 by BV 2014(B), 99,218 by AM BV2014, 632,714 by MPM OIF and 2,382,765 by UBS Oncology.

6. The shares were sold as follows: 4,742 by AM LLC, 29,958 by BV 2014, 1,998 by BV 2014(B), 1,031 by AM BV2014, 6,598 by MPM OIF and 24,741 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 $1.605 to $1.70 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: 451,674 by AM LLC, 2,852,627 by BV 2014, 190,265 by BV 2014(B), 98,187 by AM BV2014, 626,116 by MPM OIF and 2,358,024 by UBS Oncology.

9. The shares were sold as follows: 9,216 by AM LLC, 58,227 by BV 2014, 3,884 by BV 2014(B), 2,004 by AM BV2014, 12,823 by MPM OIF and 48,086 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 $1.51 to $1.62 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: 442,458 by AM LLC, 2,794,400 by BV 2014, 186,381 by BV 2014(B), 96,183 by AM BV2014, 613,293 by MPM OIF and 2,309,938 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	10/29/2025
	/s/ Ansbert Gadicke, Managing Director of MPM BioVentures 2014 LLC, the manager of MPM Asset Management Investors BV2014 LLC	10/29/2025
	/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.	10/29/2025
	/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.	10/29/2025
	/s/ Ansbert Gadicke, Managing Director of MPM BioVentures 2014 LLC, the Managing Member of MPM BioVentures 2014 GP LLC	10/29/2025
	** 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).
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FAQ

What did HOWL insiders affiliated with MPM report on Form 4?

They reported open-market sales of common stock by affiliated funds, executed under a Rule 10b5-1 plan dated September 24, 2025.

How many HOWL shares were sold and on which dates?

72,709 shares on 10/27/2025, 69,068 shares on 10/28/2025, and 134,240 shares on 10/29/2025.

What prices were received for the HOWL shares sold?

Weighted average prices were $1.72, $1.64, and $1.55, with trade ranges of $1.675–$1.82, $1.605–$1.70, and $1.51–$1.62, respectively.

How many HOWL shares did the reporting persons beneficially own after the sales?

6,645,961 after 10/27, 6,576,893 after 10/28, and 6,442,653 after 10/29, held indirectly through affiliated funds.

Are the sales part of a pre-set trading plan?

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

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

They are identified as a Director and 10% Owner of the issuer.

Which entities are involved in holding/selling the shares?

Affiliated entities include AM LLC, BV 2014, BV 2014(B), AM BV2014, MPM OIF, and UBS Oncology, as detailed in the footnotes.