Christina Teng Topsoe - 14 Aug 2025 Form 4 Insider Report for IGM Biosciences, Inc. (IGMS)

Role: Director, 10%+ Owner
Signature: /s/ Christina Teng Topsoe
Issuer symbol: IGMS
Transactions as of: 14 Aug 2025
Net transactions value: $0
Form type: 4
Filing time: 14 Aug 2025, 17:26:25 UTC
Previous filing: 02 Jul 2025
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Topsoe Christina Teng	Director, 10%+ Owner	C/O IGM BIOSCIENCES, INC., 325 E. MIDDLEFIELD ROAD, MOUNTAIN VIEW	/s/ Christina Teng Topsoe	14 Aug 2025	0001786442

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	IGMS	Common Stock	Disposed to Issuer		-54,235	-100%		0	14 Aug 2025	Direct	F1
transaction	IGMS	Common Stock	Disposed to Issuer		-10,400,564	-100%		0	14 Aug 2025	See footnote	F1, F2
transaction	IGMS	Common Stock	Disposed to Issuer		-9,800	-100%		0	14 Aug 2025	See footnote	F1, F3

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
transaction	IGMS	Non-Voting Common Stock	Disposed to Issuer	$0	-5,044,295	-100%	$0.000000	0	14 Aug 2025	Common Stock	5,044,295		See footnote	F1, F2, F4

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Christina Teng Topsoe is no longer subject to Section 16 filing requirements. Form 4 or Form 5 obligations may continue.

Explanation of Responses:

Id	Content
F1	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 and Non-Voting 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.
F2	Prior to the Merger, the shares were held directly by Topsoe Holding A/S. Jakob Haldor Topsoe, Christina Teng Topsoe, Anne Haugwitz-Hardenberg-Reventlow, Emil Oigaard, Thomas Schleicher and Birgitte Nielsen, members of the board of directors of Topsoe Holding A/S, may be deemed to share voting and investment power with respect to the shares reported herein and disclaim beneficial ownership of such shares, except to the extent of his or her pecuniary interest therein, if any.
F3	Prior to the Merger, the shares were held by Pillarcater LLC. The Reporting Person is the sole manager of Pillarcater LLC, which is wholly owned by CT Foundation (a South Dakota Trust) of which the Reporting Person is the sole beneficiary.
F4	Prior to the Merger, the shares of Non-Voting Common Stock were convertible into the Issuer's Common Stock on a 1-for-1 basis (subject to a 4.99% beneficial ownership limitation that may be increased or decreased by the holder of such shares) and had no expiration date.