Werewolf Therapeutics director-linked funds sell shares

Werewolf Therapeutics director Luke Evnin reported indirect open-market sales of the company’s common stock by affiliated investment funds.

Rhea-AI Filing Summary

Werewolf Therapeutics director Luke Evnin reported indirect open-market sales of the company’s common stock by affiliated investment funds. Over May 5–7, 2026, entities including MPM Asset Management LLC and MPM BioVentures 2014, L.P. sold a total of 100,581 shares at weighted average prices around $0.63–$0.69 per share under a pre‑established Rule 10b5-1 plan dated March 26, 2026. After these transactions, the affiliated entities collectively hold 1,578,749 shares of Werewolf Therapeutics common stock, reported as indirect holdings. Evnin disclaims beneficial ownership of these securities except to the extent of his pecuniary interest.

Insider Trade Summary 10b5-1

Net Seller: 100,581 shares

Net Sell 3 txns

Insider EVNIN LUKE

Role Director

Sold 100,581 shs ($64K)

Type	Security	Shares	Price	Value
Sale	Common Stock	79,086	$0.63	$50K
Sale	Common Stock	14,635	$0.66	$10K
Sale	Common Stock	6,860	$0.69	$5K

Holdings After Transaction: Common Stock — 1,578,749 shares (Indirect, See Footnotes)

Footnotes (11)

1. F1. Transaction effected pursuant to a plan established pursuant to Rule 10b5-1 dated March 26, 2026.
2. F2. The shares were sold as follows: 735 by MPM Asset Management LLC ("AM LLC"), 4,640 by MPM BioVentures 2014, L.P. ("BV 2014"), 310 by MPM BIoVentures 2014(B), L.P. ("BV 2014(B)"), 160 by MPM Asset Management Investors BV2014 LLC ("AM BV2014") and 1,015 by MPM Oncology Innovations Fund, L.P. ("MPM OIF").
3. F3. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $0.6616 to $0.7253 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. F4. 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. F5. The shares are held as follows: 179,188 by AM LLC, 1,131,359 by BV 2014, 75,458 by BV 2014(B), 38,939 by AM BV2014 and 247,526 by MPM OIF.
6. F6. The shares were sold as follows: 1,568 by AM LLC, 9,900 by BV 2014, 660 by BV 2014(B), 341 by AM BV2014 and 2,166 by MPM OIF.
7. F7. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $0.65 to $0.7054 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. F8. The shares are held as follows: 177,620 by AM LLC, 1,121,459 by BV 2014, 74,798 by BV 2014(B), 38,598 by AM BV2014 and 245,360 by MPM OIF.
9. F9. The shares were sold as follows: 8,473 by AM LLC, 53,499 by BV 2014, 3,568 by BV 2014(B), 1,841 by AM BV2014 and 11,705 by MPM OIF.
10. F10. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $0.62 to $0.667 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. F11. The shares are held as follows: 169,147 by AM LLC, 1,067,960 by BV 2014, 71,230 by BV 2014(B), 36,757 by AM BV2014 and 233,655 by MPM OIF.

Key Figures

Total shares sold: 100,581 shares Shares sold May 5, 2026: 6,860 shares at $0.69 Shares sold May 6, 2026: 14,635 shares at $0.66 +3 more

6 metrics

Total shares sold 100,581 shares Net open-market sales across May 5–7, 2026

Shares sold May 5, 2026 6,860 shares at $0.69 Open-market sale by affiliated entities

Shares sold May 6, 2026 14,635 shares at $0.66 Open-market sale by affiliated entities

Shares sold May 7, 2026 79,086 shares at $0.63 Open-market sale by affiliated entities

Indirect holdings after sales 1,578,749 shares Total common stock reported as indirectly held following May 7, 2026 trade

Trade plan date March 26, 2026 Date of Rule 10b5-1 trading plan governing these sales

Key Terms

Rule 10b5-1, weighted average price, pecuniary interest, indirect, +1 more

5 terms

Rule 10b5-1 regulatory

"Transaction effected pursuant to a plan established pursuant to Rule 10b5-1 dated March 26, 2026."

Rule 10b5-1 is a regulation that allows company insiders to buy or sell their shares at predetermined times, even if they have access to non-public information. It acts like setting a schedule in advance for transactions, helping prevent accusations of unfair trading. This rule provides a way for insiders to plan trades transparently, giving investors confidence that these transactions are not based on hidden information.

weighted average price financial

"The price reported in Column 4 is a weighted average price."

Weighted average price is the average price of a security where each trade or component is counted according to its size, so bigger trades pull the average more than smaller ones. Think of it like calculating the average cost of a grocery haul where items you bought more of have greater influence on the final per-item cost. Investors use it to understand the true average price paid or received, judge execution quality, and compare trading performance against market movement.

pecuniary interest financial

"The Reporting Person disclaims beneficial ownership of the securities except to the extent of his pecuniary interest therein."

indirect financial

"The shares are held as follows: 179,188 by AM LLC, 1,131,359 by BV 2014..."

open-market sale financial

"transaction_action": "open-market sale""

An open-market sale is when a shareholder sells existing shares directly on a public exchange to any willing buyer, rather than through a private deal. Think of it like putting goods on a busy market stall where price is set by supply and demand; for investors it matters because such sales increase available supply, can put short-term downward pressure on the stock price, and signal changes in liquidity or investor confidence.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What insider activity did Werewolf Therapeutics (HOWL) report for Luke Evnin?

Werewolf Therapeutics reported that investment entities associated with director Luke Evnin sold 100,581 shares of common stock in open-market transactions. These sales occurred over May 5–7, 2026 and are reported as indirect holdings, with Evnin disclaiming beneficial ownership beyond his pecuniary interest.

How many Werewolf Therapeutics (HOWL) shares were sold and at what prices?

Associated funds sold 100,581 Werewolf Therapeutics common shares. Individual transactions were 6,860 shares at $0.69, 14,635 shares at $0.66, and 79,086 shares at $0.63, with footnotes noting weighted average prices across narrower intraday trading ranges for each sale date.

How many Werewolf Therapeutics (HOWL) shares remain held after Luke Evnin’s reported sales?

After the reported transactions, the affiliated funds collectively hold 1,578,749 Werewolf Therapeutics common shares as indirect holdings. These shares are spread across several MPM-managed entities, and the filing states that Luke Evnin disclaims beneficial ownership except to the extent of his pecuniary interest.

Were the Werewolf Therapeutics (HOWL) insider sales made under a Rule 10b5-1 plan?

Yes. A filing footnote states that the transactions were effected pursuant to a Rule 10b5-1 trading plan dated March 26, 2026. Such pre-arranged plans are established in advance and allow insiders or related entities to execute trades according to predetermined instructions over time.

Who actually sold the Werewolf Therapeutics (HOWL) shares linked to Luke Evnin?

The filing explains that the shares were sold by entities including MPM Asset Management LLC, MPM BioVentures 2014, L.P., MPM BioVentures 2014(B), L.P., MPM Asset Management Investors BV2014 LLC, and MPM Oncology Innovations Fund, L.P. These investment vehicles are associated with Luke Evnin, who reports the trades indirectly.

What does ‘weighted average price’ mean in the Werewolf Therapeutics (HOWL) Form 4?

The Form 4 notes that reported prices are weighted averages for multiple trades executed within daily price ranges. For example, one day’s sales occurred between $0.6616 and $0.7253. The filing states the reporting person will provide exact trade-by-trade details upon request to investors or regulators.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Accepted by SEC EDGAR 05/07/2026 - 06:22 PM Learn about SEC filing dates

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 MASSACHUSETTS 02116

(City) (State) (Zip)

UNITED STATES

(Country)

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)

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
05/05/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

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	05/05/2026		S(1)		6,860(2)	D	$0.69(3)	1,672,470	I	See Footnotes(4)(5)
Common Stock	05/06/2026		S(1)		14,635(6)	D	$0.66(7)	1,657,835	I	See Footnotes(4)(8)
Common Stock	05/07/2026		S(1)		79,086(9)	D	$0.63(10)	1,578,749	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 March 26, 2026.

2. The shares were sold as follows: 735 by MPM Asset Management LLC ("AM LLC"), 4,640 by MPM BioVentures 2014, L.P. ("BV 2014"), 310 by MPM BIoVentures 2014(B), L.P. ("BV 2014(B)"), 160 by MPM Asset Management Investors BV2014 LLC ("AM BV2014") and 1,015 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 $0.6616 to $0.7253 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: 179,188 by AM LLC, 1,131,359 by BV 2014, 75,458 by BV 2014(B), 38,939 by AM BV2014 and 247,526 by MPM OIF.

6. The shares were sold as follows: 1,568 by AM LLC, 9,900 by BV 2014, 660 by BV 2014(B), 341 by AM BV2014 and 2,166 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 $0.65 to $0.7054 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: 177,620 by AM LLC, 1,121,459 by BV 2014, 74,798 by BV 2014(B), 38,598 by AM BV2014 and 245,360 by MPM OIF.

9. The shares were sold as follows: 8,473 by AM LLC, 53,499 by BV 2014, 3,568 by BV 2014(B), 1,841 by AM BV2014 and 11,705 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 $0.62 to $0.667 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: 169,147 by AM LLC, 1,067,960 by BV 2014, 71,230 by BV 2014(B), 36,757 by AM BV2014 and 233,655 by MPM OIF.

	/s/ Luke Evnin	05/07/2026
	** 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.
* Form 4: SEC 1474 (03-26)