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

Rhea-AI Filing Summary

Julie Hambleton, a director of IGM Biosciences (IGMS), reported a disposition of 2,000 shares on 08/14/2025. The Form 4 shows the shares were disposed in connection with a merger in which Merger Sub merged into the company and each issued share of common stock was cancelled and converted into the right to receive $1.247 in cash and one contractual contingent value right (CVR) under a Contingent Value Rights Agreement. Following the reported transaction, the filing states Ms. Hambleton beneficially owned 0 shares.

Positive

• Merger consideration defined: Each canceled share converts to $1.247 cash and one CVR, providing explicit deal economics.
• Transaction tied to corporate transaction: Disposal resulted from the merger, not an unexplained open-market sale by the director.

Negative

• None.

Insights

Corporate Governance Expert

TL;DR: Insider Form 4 reflects routine post-merger share cancellation and cash/CVR consideration; no remaining beneficial ownership reported.

The filing documents a director-level disposition tied directly to a completed merger transaction where common shares were cancelled and converted into defined merger consideration of $1.247 cash plus one CVR per share. As reported, the reporting person holds 0 shares after the disposition, indicating the insider did not retain equity post-closing. This is a transaction driven by deal mechanics rather than a voluntary open-market sale, which is important for governance context.

Securities Analyst

TL;DR: Transaction reflects deal consideration payment; Form 4 confirms conversion mechanics and no continuing direct share ownership by the director.

The Form 4 shows a disposition of 2,000 common shares on the merger closing date, with each canceled share converted into $1.247 cash and one contractual contingent value right per the Contingent Value Rights Agreement. The entry lists the relationship of the reporting person as a director and indicates 0 shares beneficially owned afterward. This aligns with a standard merger-outcome treatment of equity rather than an independent insider liquidity event.

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^*

Hambleton Julie

(Last) (First) (Middle)

C/O IGM BIOSCIENCES, INC.

325 E MIDDLEFIELD ROAD

(Street)

MOUNTAIN VIEW CA 94043

(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		2,000(1)	D	(1)	0	D

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. Pursuant to the Agreement and Plan of Merger dated July 1, 2025, by and among IGM Biosciences, Inc. (the "Company"), 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"), on August 14, 2025, Merger Sub merged with and into the Company (the "Merger"), with the Company continuing as the surviving corporation and a wholly owned subsidiary of Parent. In connection with the Merger, each issued and outstanding share of the Company's Common Stock was cancelled and converted into the right to receive (i) an amount equal to $1.247 in cash and (ii) one contractual contingent value right (a "CVR") subject to the terms and conditions of a Contingent Value Rights Agreement.

	/s/ Julie Hambleton	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 transaction did Julie Hambleton report on Form 4 for IGMS?

She reported a disposition of 2,000 common shares on 08/14/2025, listed as a sale in connection with the merger.

How much cash was each IGM Biosciences (IGMS) share converted into in the merger?

Each issued and outstanding share was converted into $1.247 in cash plus one contractual contingent value right (CVR).

Does the Form 4 show Julie Hambleton still owns IGMS shares after the transaction?

No; the filing reports 0 shares beneficially owned following the reported transaction.

What caused the reported disposition of IGMS shares?

The disposition occurred in connection with the merger in which Merger Sub merged with and into IGM Biosciences and outstanding shares were cancelled and converted into the stated consideration.

What is a CVR as referenced in the Form 4 filing?

The filing describes the CVR as a contractual contingent value right governed by a Contingent Value Rights Agreement; no further terms are provided in this Form 4.