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

Rhea-AI Filing Summary

IGM Biosciences was acquired in a transaction where holders received $1.247 per share in cash plus one contingent value right (CVR) per share. The acquiring parent completed a tender offer and the subsequent merger, after which outstanding common stock, non-voting common stock and pre-funded warrants held by reporting persons were cancelled for cash consideration and CVRs based on the transaction terms. Reported Redmile-managed funds and Jeremy Green disclosed disposition of their beneficial interests, resulting in zero beneficial ownership reported post-transaction. A Redmile managing director resigned from the issuer's board immediately prior to the merger closing.

Positive

• Completed merger providing immediate cash consideration of $1.247 per share to outstanding holders
• Contingent Value Rights (CVRs) granted per share, offering potential additional upside beyond the cash price
• Cancellation of pre-funded warrants for cash and CVRs simplified post-transaction capital structure

Negative

• Reporting persons (Redmile-managed funds and Jeremy Green) disposed of all reported holdings, now reporting 0 shares beneficially owned
• Board change: Michael Lee resigned as a director immediately prior to the merger closing, reducing prior independent representation

Insights

Financial Analyst

TL;DR: The merger delivered a cash exit of $1.247 per share plus CVRs; significant insiders fully divested their positions.

The transaction represents a full liquidity event for public holders: a fixed cash price of $1.247 per share coupled with a CVR that may provide additional contingent value. Redmile-managed vehicles and Jeremy Green reported disposing of all reported common, non-voting common and pre-funded warrant positions, reporting 0 shares beneficially owned after the closing. For valuation analysis, investors should treat the cash consideration as the guaranteed component and the CVR as contingent upside; the elimination of outstanding warrants and conversion mechanics simplified the capital structure post-closing.

Corporate Governance Expert

TL;DR: Governance changed as the company became a wholly owned subsidiary and a Redmile director resigned before closing.

The merger converted the public issuer into a private subsidiary, removing the company from public governance processes and market oversight. Reported departures include the resignation of Michael Lee from the board immediately prior to closing, indicating pre-closing board alignment with the transaction. The Form 4 discloses that reported securities were held via Redmile funds and may have been deemed beneficially owned by Jeremy Green, who now reports no remaining beneficial holdings. These are material governance changes for any remaining stakeholders tied to the CVR arrangements.

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

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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^*

Redmile Group, LLC

(Last) (First) (Middle)

ONE LETTERMAN DRIVE, BUILDING 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	X	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)

	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	08/14/2025		D		2,964,843	D	(1)	0	I	See Footnotes(5)(6)

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
Non-Voting Common Stock	(3)	08/14/2025		D			7,199,325(1)	(3)	(3)	Common Stock	7,199,325	(1)	0	I	See Footnotes(5)(6)
Pre-Funded Warrants to Purchase Common Stock	$0.01	08/14/2025		D			667,666(2)	12/11/2020	(4)	Common Stock	667,666	(2)	0	I	See Footnotes(5)(6)

1. Name and Address of Reporting Person^*

Redmile Group, LLC

(Last) (First) (Middle)

ONE LETTERMAN DRIVE, BUILDING D

SUITE D3-300

(Street)

SAN FRANCISCO CA 94129

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer

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

1. Name and Address of Reporting Person^*

Green Jeremy

(Last) (First) (Middle)

C/O REDMILE GROUP, LLC (NY OFFICE)

45 W. 27TH STREET, FLOOR 11

(Street)

NEW YORK NY 10001

(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. On August 14, 2025, pursuant to the terms of the Agreement and Plan of Merger (the "Merger Agreement"), 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 ("Issuer Shares") 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 ("CVR Agreement"). The tender offer expired one minute following 11:59 p.m., Eastern Time, on August 13, 2025 (the "Offer Closing").

2. On August 14, 2025, the Issuer completed its merger transaction with and into Merger Sub pursuant to the terms of the Merger Agreement, with the Issuer surviving as a wholly owned subsidiary of Parent (the "Merger"). At the effective date and time of the Merger (the "Merger Closing"), each outstanding and unexercised pre-funded warrant to purchase shares of the Issuer's Common Stock (each, a "Pre-Funded Warrant") was cancelled and the holder received the right to a cash amount based on the Offer Price, subject to applicable tax withholding and without interest, less the exercise price per share underlying the Pre-Funded Warrant, plus one CVR per underlying share subject to the terms and conditions of a CVR Agreement.

3. The Non-Voting Common Stock was convertible into shares of the Issuer's common stock at any time, in accordance with the terms of the Issuer's Amended and Restated Certificate of Incorporation at any time and from time to time at the holder's election on a 1-for-1 basis. The Non-Voting Common Stock had no expiration date.

4. The Pre-Funded Warrants to purchase common stock of the Issuer have no expiration date.

5. The Common Stock, Non-Voting Common Stock, and Pre-Funded Warrants of the Issuer reported herein were directly owned by certain private investment vehicles managed by Redmile (each, a "Redmile Fund"), and may have been deemed beneficially owned by Redmile as investment manager of the Redmile Funds.

6. The reported securities may also be deemed beneficially owned by Jeremy Green as the principal of Redmile (collectively with Redmile, the "Reporting Persons"). The Reporting Persons disclaim beneficial ownership of the reported securities except to the extent of their pecuniary interest therein, if any, and this Form 4 shall not be deemed an admission that either Reporting Person 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:

Michael Lee, a managing director of Redmile, resigned as a member of the board of directors of the Issuer immediately prior to the Merger Closing.

	By: /s/ Jeremy Green, Managing Member of Redmile Group, LLC	08/15/2025
	/s/ Jeremy Green	08/15/2025
	** 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).
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FAQ

What consideration did IGM Biosciences (IGMS) holders receive in the transaction?

Holders received $1.247 per share in cash plus one Contingent Value Right (CVR) per share under the CVR Agreement.

Did Redmile or Jeremy Green retain any IGMS shares after the merger?

No. The Form 4 reports that Redmile-managed vehicles and Jeremy Green disposed of the reported securities and now report 0 shares beneficially owned.

What happened to pre-funded warrants of IGMS?

At the merger closing, each outstanding and unexercised pre-funded warrant was cancelled and the holder received a cash amount equal to the Offer Price less the warrant exercise price, plus one CVR per underlying share.

Was there any change to the board of directors reported?

Yes. Michael Lee, a managing director of Redmile, resigned as a member of the issuer's board immediately prior to the merger closing.

Are the reported CVRs guaranteed cash?

No. The document states holders received one CVR per share subject to the terms and conditions of a CVR Agreement, indicating contingent rather than guaranteed value.