IGM Bio Chief Executive's Stock Sale Tied to RSU Tax Coverage

Rhea-AI Filing Summary

IGM Biosciences Chief Executive Officer and Director Mary Beth Harler reported a Form 4 filing on June 28, 2025, disclosing a transaction that occurred on June 16, 2025.

Key transaction details:

• Sold 1,522 shares of Common Stock at a weighted average price of $1.1992 per share
• The sale was specifically to cover tax withholding obligations related to the vesting of restricted stock units
• Following the transaction, Harler maintains direct beneficial ownership of 338,181 shares

The transaction was executed through multiple trades with prices ranging from $1.17 to $1.22 per share. The filing was signed by Misbah Tahir via power of attorney on June 20, 2025.

Insider Trade Summary

Net Seller: 1,522 shares ($1,825)

Net Sell 1 txn

Insider Harler Mary Beth

Role Chief Executive Officer

Sold 1,522 shs ($2K)

Type	Security	Shares	Price	Value
Sale	Common Stock	1,522	$1.1992	$2K

Holdings After Transaction: Common Stock — 338,181 shares (Direct)

Footnotes (1)

1. These shares were sold to cover tax withholding obligations in connection with the vesting of restricted stock units. This transaction was executed in multiple trades at prices ranging from $1.17 to $1.22. The price reported above reflects the weighted average sale price. The Reporting Person undertakes to provide upon request by the staff of the Securities and Exchange Commission, the Issuer, or a security holder of the Issuer full information regarding the number of shares sold at each separate sale price.

Form 4 Insider Transactions: What Each Field Means →

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

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

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^*

Harler Mary Beth

(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
X	Officer (give title below)		Other (specify below)
	Chief Executive Officer

3. Date of Earliest Transaction (Month/Day/Year)
06/16/2025

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	06/16/2025		S(1)		1,522	D	$1.1992(2)	338,181	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. These shares were sold to cover tax withholding obligations in connection with the vesting of restricted stock units.

2. This transaction was executed in multiple trades at prices ranging from $1.17 to $1.22. The price reported above reflects the weighted average sale price. The Reporting Person undertakes to provide upon request by the staff of the Securities and Exchange Commission, the Issuer, or a security holder of the Issuer full information regarding the number of shares sold at each separate sale price.

	/s/ Misbah Tahir, by power of attorney	06/20/2025
	** 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).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

How many shares did IGM Biosciences (IGMS) CEO Mary Beth Harler sell on June 16, 2025?

CEO Mary Beth Harler sold 1,522 shares of IGMS common stock on June 16, 2025. The sale was made to cover tax withholding obligations related to the vesting of restricted stock units.

What was the sale price of IGMS shares in CEO Mary Beth Harler's June 2025 transaction?

The shares were sold at a weighted average price of $1.1992 per share. The transactions were executed in multiple trades with prices ranging from $1.17 to $1.22 per share.

How many IGMS shares does CEO Mary Beth Harler own after the June 2025 transaction?

Following the reported transaction, Mary Beth Harler directly owns 338,181 shares of IGM Biosciences (IGMS) common stock.

What positions does Mary Beth Harler hold at IGM Biosciences (IGMS)?

Mary Beth Harler serves as both Chief Executive Officer and Director at IGM Biosciences, as indicated in the Form 4 filing.

Why did IGMS CEO Mary Beth Harler sell shares in June 2025?

The share sale was specifically conducted to cover tax withholding obligations in connection with the vesting of restricted stock units, as explained in the filing's footnotes.