Who executed the Werewolf Therapeutics (HOWL) share sales disclosed in this Form 4?

The shares were sold by multiple MPM-affiliated investment entities, including MPM Asset Management LLC, MPM BioVentures 2014 funds, AM BV2014 and MPM Oncology Innovations Fund. Luke Evnin is associated with these entities, but he disclaims beneficial ownership beyond his pecuniary interest in their holdings.

MPM-linked funds tied to Werewolf (NASDAQ: HOWL) sell 191,762 shares under plan

Filing Impact

(Neutral)

Filing Sentiment

(Negative)

Form Type

Rhea-AI Filing Summary

Werewolf Therapeutics director-related entities reported open-market sales of common stock. Investment entities associated with Luke Evnin sold a total of 191,762 shares of Werewolf Therapeutics, Inc. common stock in three open-market transactions on May 21, May 22 and May 26, 2026, at reported prices of $0.42, $0.45 and $0.47 per share, respectively. These transactions were effected pursuant to a Rule 10b5-1 trading plan dated March 26, 2026. After these sales, the entities collectively held 763,685 shares indirectly, spread across several MPM-managed funds and LLCs.

Insights

Pre-planned fund sales reduce exposure but leave a sizable remaining stake.

Investment entities associated with Werewolf Therapeutics director Luke Evnin reported three open-market sales totaling 191,762 common shares at prices around $0.42–$0.47. The filing notes these trades were made under a pre-established Rule 10b5-1 plan dated March 26, 2026, indicating a pre-planned disposition rather than ad hoc market timing.

The sales were executed across multiple MPM-affiliated vehicles, including AM LLC, MPM BioVentures 2014 funds, AM BV2014 and MPM Oncology Innovations Fund. Following the transactions, these entities collectively held 763,685 shares indirectly. The reporting person disclaims beneficial ownership beyond his pecuniary interest, so the activity reflects portfolio management at the fund level rather than purely personal trading.

Because there are no derivative exercises or tax-withholding events, this is a straightforward net-sell pattern by investment funds with an ongoing position. Future company filings may provide additional context on any further changes in these entities’ holdings or updates to trading plans.

Insider Trade Summary 10b5-1

Net Seller: 191,762 shares ($86,560)

Net Sell 3 txns

Insider EVNIN LUKE

Role null

Sold 191,762 shs ($87K)

Type	Security	Shares	Price	Value
Sale	Common Stock	67,950	$0.47	$32K
Sale	Common Stock	87,425	$0.45	$39K
Sale	Common Stock	36,387	$0.42	$15K

Holdings After Transaction: Common Stock — 763,685 shares (Indirect, See Footnotes)

Footnotes (1)

Transaction effected pursuant to a plan established pursuant to Rule 10b5-1 dated March 26, 2026. The shares were sold as follows: 3,899 by MPM Asset Management LLC ("AM LLC"), 24,614 by MPM BioVentures 2014, L.P. ("BV 2014"), 1,642 by MPM BIoVentures 2014(B), L.P. ("BV 2014(B)"), 847 by MPM Asset Management Investors BV2014 LLC ("AM BV2014") and 5,385 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 $0.4126 to $0.4426 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: 98,467 by AM LLC, 621,710 by BV 2014, 41,465 by BV 2014(B), 21,397 by AM BV2014 and 136,021 by MPM OIF. The shares were sold as follows: 9,367 by AM LLC, 59,139 by BV 2014, 3,944 by BV 2014(B), 2,036 by AM BV2014 and 12,939 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 $0.42 to $0.4614 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: 89,100 by AM LLC, 562,571 by BV 2014, 37,521 by BV 2014(B), 19,361 by AM BV2014 and 123,082 by MPM OIF. The shares were sold as follows: 7,280 by AM LLC, 45,965 by BV 2014, 3,066 by BV 2014(B), 1,582 by AM BV2014 and 10,057 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 $0.4436 to $0.4826 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: 81,820 by AM LLC, 516,606 by BV 2014, 34,455 by BV 2014(B), 17,779 by AM BV2014 and 113,025 by MPM OIF.

Key Figures

Total shares sold: 191,762 shares Sale price on May 26, 2026: $0.4700 per share Sale price on May 22, 2026: $0.4500 per share +5 more

8 metrics

Total shares sold 191,762 shares Aggregate Form 4 transaction summary for May 2026

Sale price on May 26, 2026 $0.4700 per share Common stock open-market sale

Sale price on May 22, 2026 $0.4500 per share Common stock open-market sale

Sale price on May 21, 2026 $0.4200 per share Common stock open-market sale

Shares remaining after trades 763,685 shares Indirect holdings following May 26, 2026 sale

Number of sale transactions 3 transactions Non-derivative open-market sales in this Form 4

Net buy/sell direction net sell of 191,762 shares Form 4 transaction summary

Rule 10b5-1 plan date March 26, 2026 Pre-established trading plan governing sales

Key Terms

Rule 10b5-1, weighted average price, beneficial ownership, pecuniary interest, +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.

beneficial ownership regulatory

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

Beneficial ownership means the person or entity that actually enjoys the benefits of owning shares or other assets — such as receiving dividends, voting rights, or price gains — even if the legal title is held in another name. For investors it matters because knowing who truly controls and profits from a company reveals who can influence decisions, exposes potential conflicts of interest or hidden concentration of power, and affects transparency and risk in the stock.

pecuniary interest financial

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

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.

Form 4 Insider Transactions: What Each Field Means →

05/26/2026 - 06:18 PM

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).

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)
05/21/2026

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)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Stock	05/21/2026		S⁽¹⁾		36,387⁽²⁾	D	$0.42⁽³⁾	919,060	I	See Footnotes⁽⁴⁾⁽⁵⁾
Common Stock	05/22/2026		S⁽¹⁾		87,425⁽⁶⁾	D	$0.45⁽⁷⁾	831,635	I	See Footnotes⁽⁴⁾⁽⁸⁾
Common Stock	05/26/2026		S⁽¹⁾		67,950⁽⁹⁾	D	$0.47⁽¹⁰⁾	763,685	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)
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)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)

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: 3,899 by MPM Asset Management LLC ("AM LLC"), 24,614 by MPM BioVentures 2014, L.P. ("BV 2014"), 1,642 by MPM BIoVentures 2014(B), L.P. ("BV 2014(B)"), 847 by MPM Asset Management Investors BV2014 LLC ("AM BV2014") and 5,385 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 $0.4126 to $0.4426 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: 98,467 by AM LLC, 621,710 by BV 2014, 41,465 by BV 2014(B), 21,397 by AM BV2014 and 136,021 by MPM OIF.

6. The shares were sold as follows: 9,367 by AM LLC, 59,139 by BV 2014, 3,944 by BV 2014(B), 2,036 by AM BV2014 and 12,939 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 $0.42 to $0.4614 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: 89,100 by AM LLC, 562,571 by BV 2014, 37,521 by BV 2014(B), 19,361 by AM BV2014 and 123,082 by MPM OIF.

9. The shares were sold as follows: 7,280 by AM LLC, 45,965 by BV 2014, 3,066 by BV 2014(B), 1,582 by AM BV2014 and 10,057 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 $0.4436 to $0.4826 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: 81,820 by AM LLC, 516,606 by BV 2014, 34,455 by BV 2014(B), 17,779 by AM BV2014 and 113,025 by MPM OIF.

	/s/ Luke Evnin	05/26/2026
	** 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)

Source: View Original Filing on SEC EDGAR

FAQ

What insider transactions were reported for Werewolf Therapeutics (HOWL) in this Form 4?

The filing reports three open-market sales of Werewolf Therapeutics common stock by entities associated with director Luke Evnin, totaling 191,762 shares. The sales occurred on May 21, May 22 and May 26, 2026 at reported prices between $0.42 and $0.47 per share.

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

Yes. The Form 4 states that the transactions were effected pursuant to a trading plan established under Rule 10b5-1 dated March 26, 2026. Such plans pre-schedule trades, indicating the timing of these sales was determined in advance rather than based on day-to-day market conditions.

How many Werewolf Therapeutics (HOWL) shares do the reporting entities hold after these sales?

After the reported transactions, the entities associated with the reporting person collectively held 763,685 shares of Werewolf Therapeutics common stock indirectly. Footnotes show these shares are spread across several MPM-managed funds and LLCs, reflecting ongoing investment exposure to the company.

What prices were received in the Werewolf Therapeutics (HOWL) insider sales?

The reported per-share prices were $0.42, $0.45 and $0.47 for the three sale dates. Footnotes explain these figures are weighted average prices for multiple trades, with actual transaction prices falling within specified ranges around each reported average price.

Does the Form 4 show option exercises or only common stock sales for Werewolf Therapeutics (HOWL)?

The Form 4 reflects only non-derivative transactions in common stock, specifically open-market sales. The derivative section is empty, and the transaction summary shows no option exercises, conversions, tax-withholding events or derivative restructurings reported in this filing.