Daniel ShinYu Chen - May 14, 2021 Form 4 Insider Report for IGM Biosciences, Inc. (IGMS)

Role: Chief Medical Officer
Signature: /s/ Misbah Tahir, by power of attorney
Stock symbol: IGMS
Transactions as of: May 14, 2021
Transactions value $: -$30,104
Form type: 4
Date filed: 5/18/2021, 09:38 PM
Next filing: May 28, 2021

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	IGMS	Common Stock	Options Exercise	$1.25K	+900	+0.77%	$1.39^*	117K	May 14, 2021	Direct	F1
transaction	IGMS	Common Stock	Tax liability	-$31.4K	-456	-0.39%	$68.76^*	117K	May 14, 2021	Direct	F2

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	Stock Option (right to buy)	Options Exercise	$0	-900	-0.26%	$0.00	342K	May 14, 2021	Common Stock	900	$1.39	Direct	F1, F3

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

Explanation of Responses:

Id	Content
F1	The option exercise was effected pursuant to a Rule 10b5-1 trading plan entered into by the Reporting Person.
F2	Represents shares withheld by the Issuer to pay the exercise price and taxes pursuant to the "net exercise" of 900 option shares.
F3	The option, originally for 361,090 shares, of which 18,950 shares have been exercised, vested as to 1/4 of the shares on August 1, 2019, and an additional 1/48 of the shares subject to the option shall vest monthly thereafter, subject to the Reporting Person remaining a service provider through each such date.