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Werewolf Therapeutics (NASDAQ: HOWL) director’s entities sell shares

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

Rhea-AI Filing Summary

Werewolf Therapeutics director-affiliated entities reported open-market sales of 105,565 shares of common stock. The transactions occurred on June 4, 5 and 8, 2026 at weighted average prices around $0.40 per share, within disclosed price ranges from $0.3706 to $0.454.

The sales were made by investment entities associated with Luke Evnin and were effected under a pre-established Rule 10b5-1 trading plan dated March 26, 2026. After these transactions, those entities collectively held 377,211 shares of Werewolf Therapeutics common stock, with Evnin disclaiming beneficial ownership beyond his pecuniary interest.

Positive

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Negative

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Insider EVNIN LUKE
Role null
Sold 105,565 shs ($43K)
Type Security Shares Price Value
Sale Common Stock 60,547 $0.40 $24K
Sale Common Stock 24,946 $0.40 $10K
Sale Common Stock 20,072 $0.44 $9K
Holdings After Transaction: Common Stock — 377,211 shares (Indirect, See Footnotes)
Footnotes (1)
  1. Transaction effected pursuant to a plan established pursuant to Rule 10b5-1 dated March 26, 2026. The shares were sold as follows: 2,150 by MPM Asset Management LLC ("AM LLC"), 13,578 by MPM BioVentures 2014, L.P. ("BV 2014"), 906 by MPM BIoVentures 2014(B), L.P. ("BV 2014(B)"), 467 by MPM Asset Management Investors BV2014 LLC ("AM BV2014") and 2,971 by MPM Oncology Innovations Fund, L.P. ("MPM OIF"). The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $0.43 to $0.4499 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. 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. The shares are held as follows: 49,573 by AM LLC, 313,005 by BV 2014, 20,875 by BV 2014(B), 10,771 by AM BV2014 and 68,480 by MPM OIF. The shares were sold as follows: 2,673 by AM LLC, 16,874 by BV 2014, 1,126 by BV 2014(B), 581 by AM BV2014 and 3,692 by MPM OIF. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $0.3918 to $0.454 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: 46,900 by AM LLC, 296,131 by BV 2014, 19,749 by BV 2014(B), 10,190 by AM BV2014 and 64,788 by MPM OIF. The shares were sold as follows: 6,487 by AM LLC, 40,957 by BV 2014, 2,732 by BV 2014(B), 1,410 by AM BV2014 and 8,961 by MPM OIF. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $0.3706 to $0.4126 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: 40,413 by AM LLC, 255,174 by BV 2014, 17,017 by BV 2014(B), 8,780 by AM BV2014 and 55,827 by MPM OIF.
Total shares sold 105,565 shares Net open-market sales on June 4, 5 and 8, 2026
Shares sold on June 8, 2026 60,547 shares Common stock, indirect ownership, open-market sale
Shares sold on June 5, 2026 24,946 shares Common stock, indirect ownership, open-market sale
Shares sold on June 4, 2026 20,072 shares Common stock, indirect ownership, open-market sale
Price per share (June 8 record) $0.40 per share Reported weighted average sale price for one transaction date
Post-transaction holdings 377,211 shares Indirectly held by affiliated entities after June 8, 2026 sales
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 ownership financial
"transaction_type: non-derivative, direct_or_indirect: I, ownership_type: indirect"
open-market sale financial
"transaction_action: open-market sale, transaction_code_description: Sale in open market or private transaction"
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.
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Form 4 Insider Transactions: What Each Field Means →
SEC Form 4
FORM 4UNITED 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)
XDirector10% Owner
Officer (give title below)Other (specify below)
2a. Foreign Trading Symbol
3. Date of Earliest Transaction (Month/Day/Year)
06/04/2026		6. Individual or Joint/Group Filing (Check Applicable Line)
XForm 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)
CodeVAmount(A) or (D)Price
Common Stock06/04/2026S(1)20,072(2)D$0.44(3)462,704ISee Footnotes(4)(5)
Common Stock06/05/2026S(1)24,946(6)D$0.4(7)437,758ISee Footnotes(4)(8)
Common Stock06/08/2026S(1)60,547(9)D$0.4(10)377,211ISee 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)
CodeV(A)(D)Date ExercisableExpiration DateTitleAmount 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: 2,150 by MPM Asset Management LLC ("AM LLC"), 13,578 by MPM BioVentures 2014, L.P. ("BV 2014"), 906 by MPM BIoVentures 2014(B), L.P. ("BV 2014(B)"), 467 by MPM Asset Management Investors BV2014 LLC ("AM BV2014") and 2,971 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 $0.43 to $0.4499 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: 49,573 by AM LLC, 313,005 by BV 2014, 20,875 by BV 2014(B), 10,771 by AM BV2014 and 68,480 by MPM OIF.
6. The shares were sold as follows: 2,673 by AM LLC, 16,874 by BV 2014, 1,126 by BV 2014(B), 581 by AM BV2014 and 3,692 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 $0.3918 to $0.454 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: 46,900 by AM LLC, 296,131 by BV 2014, 19,749 by BV 2014(B), 10,190 by AM BV2014 and 64,788 by MPM OIF.
9. The shares were sold as follows: 6,487 by AM LLC, 40,957 by BV 2014, 2,732 by BV 2014(B), 1,410 by AM BV2014 and 8,961 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 $0.3706 to $0.4126 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: 40,413 by AM LLC, 255,174 by BV 2014, 17,017 by BV 2014(B), 8,780 by AM BV2014 and 55,827 by MPM OIF.
/s/ Luke Evnin06/08/2026
** Signature of Reporting PersonDate
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)

Source: View Original Filing on SEC EDGAR

FAQ

What did HOWL insider Luke Evnin’s affiliated entities report on this Form 4?

They reported open-market sales of 105,565 shares of Werewolf Therapeutics common stock. The trades occurred on June 4, 5 and 8, 2026 at weighted average prices around $0.40 per share, as disclosed in the Form 4 and related footnotes.

Over what price ranges were Werewolf Therapeutics (HOWL) shares sold?

The filing shows weighted average sale prices near $0.40 per share. Footnotes disclose multiple trades in ranges from $0.3706 to $0.4126, from $0.3918 to $0.454, and from $0.43 to $0.4499 per share.

How many Werewolf Therapeutics (HOWL) shares remain held after these transactions?

After the reported sales, the entities associated with Luke Evnin collectively held 377,211 shares of Werewolf Therapeutics common stock. A detailed footnote breaks this total among several investment entities, reflecting continuing indirect ownership following the June 2026 transactions.

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

Yes. A footnote states the transactions were effected under a Rule 10b5-1 trading plan dated March 26, 2026. Such pre-arranged plans schedule trades in advance, helping separate routine portfolio management from discretionary, timing-sensitive decisions by insiders.

Who actually sold the Werewolf Therapeutics (HOWL) shares reported for Luke Evnin?

The shares were sold by several MPM-affiliated entities, including AM LLC, BV 2014, BV 2014(B), AM BV2014 and MPM OIF. The Form 4 notes Luke Evnin’s roles in these entities and states he disclaims beneficial ownership except to the extent of his pecuniary interest.

How are the indirect HOWL holdings allocated among the MPM entities?

A footnote shows post-transaction holdings of 40,413 shares by AM LLC, 255,174 by BV 2014, 17,017 by BV 2014(B), 8,780 by AM BV2014 and 55,827 by MPM OIF, totaling the reported 377,211 Werewolf Therapeutics common shares.