[Form 4] IGM Biosciences, Inc. Insider Trading Activity

Rhea-AI Filing Summary

IGM Biosciences (IGMS) Form 4 shows that on August 14, 2025 12,712 shares of Common Stock were disposed of, leaving the reporting person with 0 shares after the transaction. The sale occurred pursuant to the closing of a tender offer under an Agreement and Plan of Merger dated July 1, 2025, in which Merger Sub purchased outstanding common and non-voting shares for $1.247 per share in cash plus one contingent value right (CVR) per share. The reported shares were held by Michael Lee as a nominee for Redmile Group, LLC; Redmile and Jeremy Green disclaim beneficial ownership except for any pecuniary interest. Mr. Lee resigned from the issuer’s board immediately prior to the merger becoming effective.

Positive

• Tender offer completed pursuant to the Agreement and Plan of Merger with consideration of $1.247 cash per share
• Contingent Value Right (CVR) issued one per share as part of consideration

Negative

• Reporting person resigned from the issuer’s board immediately prior to the merger effective time
• Reporting person holds 0 shares following the reported disposition

Insights

Securities Analyst

TL;DR: Insider reported disposition of all reported shares due to a merger tender offer at $1.247 plus a CVR; reporting person resigned from the board.

The Form 4 documents a routine Section 16 disclosure tied to an announced merger and tender offer. The key facts are the per-share cash consideration of $1.247, the additional CVR per share, and the complete disposition resulting in zero post-transaction ownership by the reporting person. The filing clarifies nominee holdings and disclaimers by Redmile and Jeremy Green, which is typical where an investment manager holds shares in nominee capacity. There are no other compensatory or option-based derivative items reported.

Corporate Governance Expert

TL;DR: Governance disclosure shows a director-held nominee position disposed in connection with a completed merger; resignation occurred immediately before effectiveness.

The report confirms that Michael Lee held securities in nominee capacity for Redmile and assigned economic and voting rights to Redmile, then disclaimed beneficial ownership. The resignation from the board immediately prior to the merger’s effective time is documented in the remarks. This filing serves to record the transfer of shares under the merger terms and to update Section 16 reporting status for the former director; it does not disclose any contested governance actions or litigation related matters.

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

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X

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^*

Lee Michael Stewart

(Last) (First) (Middle)

C/O REDMILE GROUP, LLC

ONE LETTERMAN DR., BLDG. D, SUITE D3-300

(Street)

SAN FRANCISCO CA 94129

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
IGM Biosciences, Inc. [ IGMS ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

3. Date of Earliest Transaction (Month/Day/Year)
08/14/2025

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

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

X	Form filed by One Reporting Person
	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	08/14/2025		D		12,712(1)	D	(1)	0	D(2)(3)

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. On August 14, 2025, pursuant to the terms of the Agreement and Plan of Merger, dated as of July 1, 2025, among the Issuer, Concentra Biosciences, LLC, a Delaware limited liability company ("Parent"), and Concentra Merger Sub V, Inc., a Delaware corporation and a wholly owned subsidiary of Parent ("Merger Sub"), Merger Sub completed a tender offer to purchase all outstanding shares of the Issuer's Common Stock and Non-Voting Common Stock in exchange for (a) a price per share of $1.247 in cash (the "Offer Price"), subject to applicable tax withholding and without interest, plus (b) one contingent value right ("CVR") per share subject to the terms and conditions of a Contingent Value Rights Agreement . The tender offer expired one minute following 11:59 p.m., Eastern Time, on August 13, 2025 (the "Offer Closing").

2. The reported securities were granted to Michael Lee, a managing director of Redmile Group, LLC ("Redmile"), in connection with his service as a member of the Board of Directors of the Issuer. Pursuant to the policies of Redmile, Mr. Lee held these securities as a nominee on behalf, and for the sole benefit, of Redmile and assigned all economic, pecuniary and voting rights in respect of the securities to Redmile. Mr. Lee disclaimed beneficial ownership of the reported securities, and the filing of this Form 4 shall not be deemed an admission that Mr. Lee was the beneficial owner of the securities for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose.

3. The securities may also be deemed beneficially owned by Jeremy Green as the principal of Redmile. Redmile and Mr. Green disclaim beneficial ownership of the securities except to the extent of their pecuniary interest therein, if any, and this Form 4 shall not be deemed an admission that Redmile or Mr. Green is the beneficial owner of the securities for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose.

Remarks:

Mr. Lee, a managing director of Redmile, resigned as a member of the board of directors of the Issuer immediately prior to the effective date and time of the merger between Issuer and Merger Sub.

	/s/ Michael Lee	08/14/2025
	** 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 the Form 4 filed for IGMS report?

The Form 4 reports the disposition of 12,712 common shares on August 14, 2025, leaving the reporting person with 0 shares.

What consideration did the merger tender offer provide to IGMS shareholders?

The tender offer provided $1.247 in cash per share, subject to tax withholding, plus one contingent value right (CVR) per share.

Why does the Form 4 list Redmile Group and Jeremy Green disclaimers?

The reported securities were held by Michael Lee as a nominee for Redmile Group, LLC; Redmile and Jeremy Green disclaim beneficial ownership except for any pecuniary interest.

Did the reporting person remain on the IGM Biosciences board after the transaction?

No. The remarks state Michael Lee resigned as a member of the board immediately prior to the merger’s effective date and time.

Does the Form 4 disclose any derivative securities or options?

No. Table II contains no entries for derivative securities, and only the non-derivative disposition is reported.