IGMS / IGM Biosciences, Inc. - Pengajuan SECLaporan Tahunan, Pernyataan Proksi

IGM Biosciences, Inc.
US ˙ NasdaqGS ˙ US4495851085
HINDI NA ACTIVE ANG SIMBONG ITO

Mga Batayang Estadistika
LEI 5493008XCQES2N0VY969
CIK 1496323
SEC Filings
All companies that sell securities in the United States must register with the Securities and Exchange Commission (SEC) and file reports on a regular basis. These reports include company annual reports (10K, 10Q), news updates (8K), investor presentations (found in 8Ks), insider trades (form 4), ownership reports (13D, and 13G), and reports related to the specific securities sold, such as registration statements and prospectus. This page shows recent SEC filings related to IGM Biosciences, Inc.
SEC Filings (Chronological Order)
Halaman ini menyediakan daftar lengkap dan kronologis dari Pengajuan SEC, tidak termasuk pengajuan kepemilikan yang kami sediakan di tempat lain.
August 25, 2025 15-12G

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 15

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 15 CERTIFICATION AND NOTICE OF TERMINATION OF REGISTRATION UNDER SECTION 12(g) OF THE SECURITIES EXCHANGE ACT OF 1934 OR SUSPENSION OF DUTY TO FILE REPORTS UNDER SECTIONS 13 AND 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. 001-39045 Commission File Number IGM BIOSCIENCES, INC. (Exact name of registrant as specified in its

August 14, 2025 POS AM

As filed with the Securities and Exchange Commission on August 14, 2025

As filed with the Securities and Exchange Commission on August 14, 2025 Registration No.

August 14, 2025 POS AM

As filed with the Securities and Exchange Commission on August 14, 2025

As filed with the Securities and Exchange Commission on August 14, 2025 Registration No.

August 14, 2025 EX-3.2

AMENDED AND RESTATED BYLAWS IGM BIOSCIENCES, INC. (a Delaware corporation) ARTICLE I CORPORATE OFFICES

EX-3.2 Exhibit 3.2 AMENDED AND RESTATED BYLAWS OF IGM BIOSCIENCES, INC. (a Delaware corporation) ARTICLE I CORPORATE OFFICES Section 1.1 Registered Office. The registered office of IGM Biosciences, Inc. (the “Corporation”) shall be fixed in the Certificate of Incorporation of the Corporation (as may be amended or modified from time to time, the “Certificate of Incorporation”). Section 1.2 Other Of

August 14, 2025 POS AM

As filed with the Securities and Exchange Commission on August 14, 2025

As filed with the Securities and Exchange Commission on August 14, 2025 Registration No.

August 14, 2025 SC TO-T/A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE TO TENDER OFFER STATEMENT UNDER SECTION 14(d)(1) OR 13(e)(1) OF THE SECURITIES EXCHANGE ACT OF 1934 (Amendment No. 1) IGM BIOSCIENCES, INC. (Name of Subject Company (Iss

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE TO TENDER OFFER STATEMENT UNDER SECTION 14(d)(1) OR 13(e)(1) OF THE SECURITIES EXCHANGE ACT OF 1934 (Amendment No. 1) IGM BIOSCIENCES, INC. (Name of Subject Company (Issuer)) CONCENTRA BIOSCIENCES, LLC (Name of Filing Persons (Co-Offeror 1)) CONCENTRA MERGER SUB V, INC. (Name of Filing Persons (Co-Offeror 2)) TANG CAP

August 14, 2025 S-8 POS

As filed with the Securities and Exchange Commission on August 14, 2025

As filed with the Securities and Exchange Commission on August 14, 2025 Registration No.

August 14, 2025 POS AM

As filed with the Securities and Exchange Commission on August 14, 2025

As filed with the Securities and Exchange Commission on August 14, 2025 Registration No.

August 14, 2025 EX-99.25

EX-99.25

igms-form25

August 14, 2025 EX-99.(D)(5)

CONTINGENT VALUE RIGHTS AGREEMENT

Exhibit (d)(5) CONTINGENT VALUE RIGHTS AGREEMENT THIS CONTINGENT VALUE RIGHTS AGREEMENT, dated as of August 14, 2025 (this “Agreement”), is entered into by and between Concentra Biosciences, LLC, a Delaware limited liability company (the “Parent”), Concentra Merger Sub V, Inc.

August 14, 2025 S-8 POS

As filed with the Securities and Exchange Commission on August 14, 2025

As filed with the Securities and Exchange Commission on August 14, 2025 Registration No.

August 14, 2025 S-8 POS

As filed with the Securities and Exchange Commission on August 14, 2025

As filed with the Securities and Exchange Commission on August 14, 2025 Registration No.

August 14, 2025 S-8 POS

As filed with the Securities and Exchange Commission on August 14, 2025

As filed with the Securities and Exchange Commission on August 14, 2025 Registration No.

August 14, 2025 S-8 POS

As filed with the Securities and Exchange Commission on August 14, 2025

As filed with the Securities and Exchange Commission on August 14, 2025 Registration No.

August 14, 2025 S-8 POS

As filed with the Securities and Exchange Commission on August 14, 2025

As filed with the Securities and Exchange Commission on August 14, 2025 Registration No.

August 14, 2025 S-8 POS

As filed with the Securities and Exchange Commission on August 14, 2025

As filed with the Securities and Exchange Commission on August 14, 2025 Registration No.

August 14, 2025 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): August 14, 2025 IGM Biosciences,

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): August 14, 2025 IGM Biosciences, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-39045 77-0349194 (State or Other Jurisdiction of Incorporation) (Commission F

August 14, 2025 POS AM

As filed with the Securities and Exchange Commission on August 14, 2025

As filed with the Securities and Exchange Commission on August 14, 2025 Registration No.

August 14, 2025 EX-3.1

AMENDED AND RESTATED CERTIFICATE OF INCORPORATION IGM BIOSCIENCES, INC.

EX-3.1 Exhibit 3.1 AMENDED AND RESTATED CERTIFICATE OF INCORPORATION OF IGM BIOSCIENCES, INC. I. The name of this corporation is IGM Biosciences, Inc. (the “Corporation”). II. The registered office of the Corporation in the State of Delaware shall be Corporation Service Center, 251 Little Falls Drive, Wilmington, New Castle County, Delaware, 19808, and the name of the registered agent of the Corpo

August 14, 2025 SC 14D9/A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14D-9 Solicitation/Recommendation Statement Under Section 14(d)(4) of the Securities Exchange Act of 1934 (Amendment No.1) IGM Biosciences, Inc. (Name of Subject Company

SC 14D9/A UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14D-9 Solicitation/Recommendation Statement Under Section 14(d)(4) of the Securities Exchange Act of 1934 (Amendment No.1) IGM Biosciences, Inc. (Name of Subject Company) IGM Biosciences, Inc. (Name of Persons Filing Statement) Common Stock, $0.01 par value per share (Title of Class of Securities) 449585108

August 14, 2025 S-8 POS

As filed with the Securities and Exchange Commission on August 14, 2025

As filed with the Securities and Exchange Commission on August 14, 2025 Registration No.

July 31, 2025 10-Q

Table of Contents Condensed Balance Sheets Condensed Statements of Operations Condensed Statements of Comprehensive Income (Loss) Condensed Statements of Stockholders’ Equity Condensed Statements of Stockholders’ Equity Condensed Statements of Cash F

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2025 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 00

July 16, 2025 SC TO-T

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE TO TENDER OFFER STATEMENT UNDER SECTION 14(d)(1) OR 13(e)(1) OF THE SECURITIES EXCHANGE ACT OF 1934 IGM BIOSCIENCES, INC. (Name of Subject Company (Issuer)) CONCENTRA BI

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE TO TENDER OFFER STATEMENT UNDER SECTION 14(d)(1) OR 13(e)(1) OF THE SECURITIES EXCHANGE ACT OF 1934 IGM BIOSCIENCES, INC. (Name of Subject Company (Issuer)) CONCENTRA BIOSCIENCES, LLC (Name of Filing Persons (Co-Offeror 1)) CONCENTRA MERGER SUB V, INC. (Name of Filing Persons (Co-Offeror 2)) TANG CAPITAL PARTNERS, LP

July 16, 2025 SC 14D9

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14D-9 Solicitation/Recommendation Statement Under Section 14(d)(4) of the Securities Exchange Act of 1934 IGM Biosciences, Inc. (Name of Subject Company) IGM Biosciences

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14D-9 Solicitation/Recommendation Statement Under Section 14(d)(4) of the Securities Exchange Act of 1934 IGM Biosciences, Inc. (Name of Subject Company) IGM Biosciences, Inc. (Name of Persons Filing Statement) Common Stock, $0.01 par value per share (Title of Class of Securities) 449585108 (CUSIP Nu

July 16, 2025 EX-99.(D)(3)

Limited Guaranty, dated as of July 1, 2025 (incorporated herein by reference to Exhibit (d)(3) to the Schedule TO).

Exhibit (d)(3) LIMITED GUARANTY This Limited Guaranty, dated as of July 1, 2025 (as may be amended, restated, supplemented or otherwise modified, this “Limited Guaranty”), by Tang Capital Partners, LP (the “Guarantor”), is made in favor of IGM Biosciences, Inc.

July 16, 2025 EX-99.(A)(1)(D)

Form of Letter to Clients for Use by Brokers, Dealers, Commercial Banks, Trust Companies and Other Nominees (incorporated by reference to Exhibit (a)(1)(D) to the Schedule TO).

Exhibit (a)(1)(D) Offer to Purchase All Outstanding Shares of Common Stock of   IGM BIOSCIENCES, INC.

July 16, 2025 EX-99.(A)(1)(C)

Form of Letter to Brokers, Dealers, Commercial Banks, Trust Companies and Other Nominees (incorporated herein by reference to Exhibit (a)(1)(C) to the Schedule TO).

Exhibit (a)(1)(C) Offer to Purchase All Outstanding Shares of Common Stock of   IGM BIOSCIENCES, INC.

July 16, 2025 EX-99.(A)(1)(B)

Form of Letter of Transmittal (incorporated herein by reference to Exhibit (a)(1)(B) to the Schedule TO).

Exhibit (a)(1)(B) [This space is intentionally left blank and reserved for registered shareholder detail] Letter of Transmittal To Tender Shares of Common Stock of   IGM BIOSCIENCES, INC.

July 16, 2025 EX-FILING FEES

Calculation of Filing Fee Tables SC TO-T (Form Type) IGM Biosciences, Inc. (Name of Subject Company – Issuer) Concentra Biosciences, LLC (Names of Filing Persons — Offeror) Table 1: Transaction Valuation

Exhibit 107 Calculation of Filing Fee Tables SC TO-T (Form Type) IGM Biosciences, Inc.

July 16, 2025 EX-99.(D)(2)

Confidentiality Agreement, dated May 27, 2025, by and between IGM and Concentra Biosciences, LLC (incorporated herein by reference to Exhibit (d)(2) to the Schedule TO).

Exhibit (d)(2) CONFIDENTIAL May 27, 2025 Concentra Biosciences, LLC 4747 Executive Drive, Suite 210 San Diego, CA 92121 Attention: Kevin Tang, Chief Executive Officer Confidentiality Agreement Ladies and Gentlemen: In connection with a potential negotiated strategic transaction between IGM Biosciences, Inc.

July 16, 2025 EX-99.(A)(1)(A)

Offer to Purchase, dated July 16, 2025 (incorporated herein by reference to Exhibit (a)(1)(A) to the Schedule TO).

TABLE OF CONTENTS Exhibit (a)(1)(A) Offer to Purchase   All Outstanding Shares of Common Stock of   IGM BIOSCIENCES, INC.

July 1, 2025 SC14D9C

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14D-9 Solicitation/Recommendation Statement under Section 14(d)(4) of the Securities Exchange Act of 1934 IGM BIOSCIENCES, INC. (Name of Subject Company) IGM BIOSCIENCES

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14D-9 Solicitation/Recommendation Statement under Section 14(d)(4) of the Securities Exchange Act of 1934 IGM BIOSCIENCES, INC. (Name of Subject Company) IGM BIOSCIENCES, INC. (Name of Person(s) Filing Statement) Common Stock, $0.01 par value per share (Title of Class of Securities) 449585108 (CUSIP Number of Class of

July 1, 2025 EX-99.2

Email to Employees, first used July 1, 2025

EX-99.2 Exhibit 99.2 IGM Colleagues, As you know, we have been working over the past several months to determine a strategic path forward for our company. Today we announced that we have entered into a definitive merger agreement with Concentra Biosciences, LLC and Concentra Merger Sub V, Inc., whereby Concentra will acquire IGM Biosciences for $1.247 in cash per share of IGM Biosciences common st

July 1, 2025 EX-99.1

IGM Biosciences Enters into Agreement to Be Acquired by Concentra Biosciences for $1.247 in Cash per Share Plus a Contingent Value Right

Exhibit 99.1 IGM Biosciences Enters into Agreement to Be Acquired by Concentra Biosciences for $1.247 in Cash per Share Plus a Contingent Value Right Mountainview, Calif. July 1, 2025 – IGM Biosciences, Inc. (Nasdaq: IGMS), a biotechnology company that has focused on developing engineered IgM-based therapeutic antibodies, today announced that it has entered into a definitive merger agreement (the

July 1, 2025 EX-10.1

Form of Contingent Value Rights Agreement by and among Concentra Biosciences, LLC, Concentra Merger Sub V, Inc. and the other parties thereto.

Exhibit 10.1 FORM OF CONTINGENT VALUE RIGHTS AGREEMENT THIS CONTINGENT VALUE RIGHTS AGREEMENT, dated as of [•] (this “Agreement”), is entered into by and between Concentra Biosciences, LLC, a Delaware limited liability company (the “Parent”), Concentra Merger Sub V, Inc., a Delaware corporation and a wholly owned Subsidiary of Parent (the “Merger Sub”), [•], as Rights Agent (as defined herein), an

July 1, 2025 8-K

Regulation FD Disclosure

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): July 1, 2025 IGM Biosciences, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-39045 77-0349194 (State or Other Jurisdiction of Incorporation) (Commission File

July 1, 2025 EX-2.1

Agreement and Plan of Merger, dated July 1, 2025, by and among Concentra Biosciences, LLC, Concentra Merger Sub V, Inc. and IGM Biosciences, Inc.

Exhibit 2.1 AGREEMENT AND PLAN OF MERGER DATED AS OF JULY 1, 2025 AMONG CONCENTRA BIOSCIENCES, LLC, CONCENTRA MERGER SUB V, INC. AND IGM BIOSCIENCES, INC. TABLE OF CONTENTS Page ARTICLE I DEFINITIONS 2 SECTION 1.01 Definitions 2 SECTION 1.02 Interpretation and Rules of Construction 12 ARTICLE II THE OFFER 13 SECTION 2.01 The Offer 13 SECTION 2.02 Company Actions 17 ARTICLE III THE MERGER 18 SECTIO

July 1, 2025 EX-99.1

Press Release, dated as of July 1, 2025

Exhibit 99.1 IGM Biosciences Enters into Agreement to Be Acquired by Concentra Biosciences for $1.247 in Cash per Share Plus a Contingent Value Right Mountainview, Calif. July 1, 2025 – IGM Biosciences, Inc. (Nasdaq: IGMS), a biotechnology company that has focused on developing engineered IgM-based therapeutic antibodies, today announced that it has entered into a definitive merger agreement (the

June 11, 2025 8-K

Notice of Delisting or Failure to Satisfy a Continued Listing Rule or Standard; Transfer of Listing

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): June 6, 2025 IGM Biosciences, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-39045 77-0349194 (State or Other Jurisdiction of Incorporation) (Commission File

May 29, 2025 EX-10.1

Second Amendment to Lease, dated May 23, 2025

Exhibit 10.1 Re: 325 E. Middlefield Road 265 N. Whisman Avenue Mountain View, California SECOND AMENDMENT TO LEASE THIS SECOND AMENDMENT TO LEASE (this “Amendment”) has been entered into as of (but not necessarily on) May 23, 2025, by Real Property Investments, LLC, a Colorado limited liability company (“Landlord”) and IGM Biosciences, Inc., a Delaware corporation (“Tenant”). RECITALS: A. Landlord

May 29, 2025 8-K

Entry into a Material Definitive Agreement, Termination of a Material Definitive Agreement, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): May 23, 2025 IGM Biosciences, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-39045 77-0349194 (State or Other Jurisdiction of Incorporation) (Commission File

May 13, 2025 10-Q

Table of Contents Condensed Balance Sheets Condensed Statements of Operations Condensed Statements of Comprehensive Loss Condensed Statements of Stockholders’ Equity Condensed Statements of Cash Flows Note 1. Organization Note 2. Summary of Significa

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2025 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 0

May 8, 2025 8-K

Regulation FD Disclosure

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): May 5, 2025 IGM Biosciences, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-39045 77-0349194 (State or Other Jurisdiction of Incorporation) (Commission File

April 30, 2025 10-K/A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K/A

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K/A (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2024 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 FOR THE TRANSITION PERIOD FROM TO Commission File Number 001-3

March 6, 2025 8-K/A

Costs Associated with Exit or Disposal Activities

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K/A (Amendment No.1) CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): January 7, 2025 IGM Biosciences, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-39045 77-0349194 (State or Other Jurisdiction of Incorpora

March 6, 2025 EX-19.1

Insider Trading Policy and Guidelines with Respect to Certain Transactions in Securities.

Exhibit 19.1 IGM BIOSCIENCES, INC. INSIDER TRADING POLICY AND GUIDELINES WITH RESPECT TO CERTAIN TRANSACTIONS IN SECURITIES (Updated as of September 12, 2023) TABLE OF CONTENTS Page INTRODUCTION 1 Legal prohibitions on insider trading 1 Detection and prosecution of insider trading 1 Compliance Officers 1 Reporting violations 1 Personal responsibility 2 PERSONS AND TRANSACTIONS COVERED BY THIS POLI

March 6, 2025 S-8

As filed with the Securities and Exchange Commission on March 6, 2025

As filed with the Securities and Exchange Commission on March 6, 2025 Registration No.

March 6, 2025 EX-4.1

Specimen common stock certificate of the Registrant.

Exhibit 4.1 NUMBER SHARES igm biosciences[LOGO] CUSIP 449585 10 8 SEE REVERSE FOR CERTAIN DEFINITIONS AND LEGENDS INCORPORATED UNDER THE LAWS OF THE STATE OF DELAWARE This certifies that is the record holder of FULLY PAID AND NON-ASSESSABLE SHARES OF VOTING COMMON STOCK, $0.01 PAR VALUE PER SHARE, OF IGM Biosciences, Inc.transferable on the books of the corporation in person or by duly authorized

March 6, 2025 10-K

Annual Report on Form 10-K for the fiscal year ended December 31, 2024

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2024 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 FOR THE TRANSITION PERIOD FROM TO Commission File Number 001-390

March 6, 2025 EX-10.3

Amended and Restated 2018 Omnibus Incentive Plan, amended June 23, 2023, and forms of agreements thereunder.

Exhibit 10.3 IGM BIOSCIENCES, INC. AMENDED AND RESTATED 2018 OMNIBUS INCENTIVE PLAN (as amended and restated effective June 23, 2023) 1. Purposes of the Plan. The purposes of this Plan are: • to attract and retain the best available personnel for positions of substantial responsibility, • to provide additional incentive to Employees, Directors and Consultants, and • to promote the success of the C

March 6, 2025 EX-FILING FEES

Filing Fee Table

Exhibit 107 Calculation of Filing Fee Tables Form S-8 (Form Type) IGM BIOSCIENCES, Inc.

January 10, 2025 EX-99.1

IGM Biosciences Provides Strategic Update on Autoimmunity Pipeline Programs – Company halting further development of imvotamab (CD20 x CD3) and IGM-2644 (CD38 x CD3) – – Company reducing its workforce by 73% – – Cash and investments of $183.8 million

Exhibit 99.1 IGM Biosciences Provides Strategic Update on Autoimmunity Pipeline Programs – Company halting further development of imvotamab (CD20 x CD3) and IGM-2644 (CD38 x CD3) – – Company reducing its workforce by 73% – – Cash and investments of $183.8 million (unaudited) as of December 31, 2024 – MOUNTAIN VIEW, Calif., January 9, 2025 – IGM Biosciences, Inc. (Nasdaq: IGMS), a biotechnology com

January 10, 2025 8-K

Regulation FD Disclosure, Financial Statements and Exhibits, Costs Associated with Exit or Disposal Activities, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): January 7, 2025 IGM Biosciences, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-39045 77-0349194 (State or Other Jurisdiction of Incorporation) (Commission F

November 8, 2024 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2024 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Numbe

November 8, 2024 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): November 08, 2024 IGM Biosciences, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-39045 77-0349194 (State or Other Jurisdiction of Incorporation) (Commission

November 8, 2024 EX-10.2

Employment Agreement, by and between the Registrant and Mary Beth Harler, M.D., dated September 30, 2024

Exhibit 10.2 EMPLOYMENT AGREEMENT This EMPLOYMENT AGREEMENT, dated as of September 30, 2024 (the “Effective Date”), is between IGM Biosciences, Inc., a Delaware corporation (the “Company”) and Mary Beth Harler (“Executive”). In consideration of the mutual covenants contained herein, the parties agree as follows: 1. Employment. Beginning on the Effective Date, Executive will be appointed the Compan

November 8, 2024 EX-10.1

Transition and Consulting Agreement, by and between the Registrant and Fred Schwarzer, dated September 30, 2024

Exhibit 10.1 TRANSITION AND CONSULTING AGREEMENT This Transition and Consulting Agreement (“Agreement”) is made effective as of September 30, 2024 (the “Effective Date”), by and between IGM Biosciences, Inc., a Delaware corporation having an address at 325 East Middlefield Road, Mountain View, CA 94043 (“IGM”), and Fred Schwarzer, an individual having an address at 553 Mimosa Court, Los Altos, CA

November 8, 2024 EX-10.4

Consulting Agreement, by and between the Registrant and William Strohl, Ph.D., dated August 8, 2024

Exhibit 10.4 CONSULTING AGREEMENT This Consulting Agreement ("Agreement") is made as of the date of the last signature below (the “Effective Date”), by and between IGM Biosciences, Inc., a Delaware corporation having an address at 325 East Middlefield Road, Mountain View, CA 94043 (“IGM”), and William Strohl, an individual having an address at 1086 Tullo Farm Road, Bridgewater NJ 08807 ("Consultan

November 8, 2024 8-K/A

Costs Associated with Exit or Disposal Activities

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K/A (Amendment No.1) CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): September 27, 2024 IGM Biosciences, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-39045 77-0349194 (State or Other Jurisdiction of Incorp

November 8, 2024 EX-10.3

Transition and Consulting Agreement, by and between the Registrant and Bruce Keyt, dated October 1, 2024

Exhibit 10.3 TRANSITION AND CONSULTING AGREEMENT This Transition and Consulting Agreement (“Agreement”) is made effective as of October 1, 2024 (the “Effective Date”), by and between IGM Biosciences, Inc., a Delaware corporation having an address at 325 East Middlefield Road, Mountain View, CA 94043 (“IGM”), and Bruce Keyt, an individual having an address at 1180 Lakeview Drive, Hillsborough, CA 9

November 8, 2024 EX-99.1

IGM Biosciences Announces Third Quarter 2024 Financial Results and Provides Corporate Update – Imvotamab (CD20 x CD3) trials in rheumatoid arthritis, systemic lupus erythematosus and myositis ongoing; initial clinical data expected by mid-2025 – – IG

Exhibit 99.1 IGM Biosciences Announces Third Quarter 2024 Financial Results and Provides Corporate Update – Imvotamab (CD20 x CD3) trials in rheumatoid arthritis, systemic lupus erythematosus and myositis ongoing; initial clinical data expected by mid-2025 – – IGM-2644 (CD38 x CD3) expected to enter clinical study for generalized myasthenia gravis by year-end 2024 – – Cash runway expected to fund

October 3, 2024 EX-99.1

– Company to prioritize its pipeline of T cell engagers in autoimmune diseases, including ongoing clinical development of imvotamab in rheumatoid arthritis and systemic lupus erythematosus – – Mary Beth Harler, M.D., appointed as Chief Executive Offi

Exhibit 99.1 IGM Biosciences Announces Strategic Pivot to Focus Exclusively on Autoimmunity September 30, 2024 – Company to prioritize its pipeline of T cell engagers in autoimmune diseases, including ongoing clinical development of imvotamab in rheumatoid arthritis and systemic lupus erythematosus – – Mary Beth Harler, M.D., appointed as Chief Executive Officer and to Board of Directors – – Cash

October 3, 2024 8-K

Costs Associated with Exit or Disposal Activities

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): September 27, 2024 IGM Biosciences, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-39045 77-0349194 (State or Other Jurisdiction of Incorporation) (Commissio

August 14, 2024 EX-3.1

Amended and Restated Certificate of Incorporation of the Registrant, as amended

Exhibit 3.1 AMENDED AND RESTATED CERTIFICATE OF INCORPORATION OF IGM BIOSCIENCES, INC. IGM Biosciences, Inc., a corporation organized and existing under the laws of the State of Delaware (the “Corporation”), does hereby certify as follows: A. The name of the Corporation is IGM Biosciences, Inc. The Corporation was originally incorporated pursuant to the General Corporation Law of the State of Dela

August 14, 2024 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2024 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 00

August 14, 2024 8-K

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): August 14, 2024 IGM Biosciences, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-39045 77-0349194 (State or Other Jurisdiction of Incorporation) (Commission F

August 14, 2024 EX-99.1

IGM Biosciences Announces Second Quarter 2024 Financial Results and Provides Corporate Update – Enrollment complete in aplitabart randomized colorectal cancer clinical trial; top-line PFS results expected by the end of 1Q25 – – Second dose cohort cle

Exhibit 99.1 IGM Biosciences Announces Second Quarter 2024 Financial Results and Provides Corporate Update – Enrollment complete in aplitabart randomized colorectal cancer clinical trial; top-line PFS results expected by the end of 1Q25 – – Second dose cohort cleared in imvotamab rheumatoid arthritis clinical trial – – First dose cohort cleared in imvotamab systemic lupus erythematosus clinical tr

August 2, 2024 EX-99.1

JOINT FILING AGREEMENT

EX-99.1 2 d820351dex991.htm EX-99.1 EXHIBIT 1 JOINT FILING AGREEMENT The undersigned agree that the statement on Schedule 13G with respect to the securities of IGM Biosciences, Inc. is, and any amendments thereto signed by each or any of the undersigned shall be, filed on behalf of each of such person pursuant to and in accordance with the provisions of Rule 13d-1(k) under the Securities Exchange

August 2, 2024 SC 13G/A

IGMS / IGM Biosciences, Inc. / Invus Global Management, LLC - SC 13G/A Passive Investment

SC 13G/A 1 d820351dsc13ga.htm SC 13G/A UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934* (Amendment No. 4) IGM Biosciences, Inc. (Name of Issuer) Common Stock, par value $0.01 per share (Title of Class of Securities) 449585108 (CUSIP Number) July 25, 2024 (Date of Event Which Requires Filing of this Statement) Check the

July 22, 2024 SC TO-I/A

SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 AMENDMENT NO. 3 SCHEDULE TO Tender Offer Statement Under Section 14(d)(1) or 13(e)(1) of the Securities Exchange Act of 1934 IGM BIOSCIENCES, INC. (Name of Subject Company (Issuer) and Filing

SC TO-I/A SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 AMENDMENT NO. 3 TO SCHEDULE TO Tender Offer Statement Under Section 14(d)(1) or 13(e)(1) of the Securities Exchange Act of 1934 IGM BIOSCIENCES, INC. (Name of Subject Company (Issuer) and Filing Person (Offeror)) Options to Purchase Common Stock Covering Common Stock, $0.01 par value (Title of Class of Securities) 449585108 (CUSIP

July 5, 2024 8-K

Regulation FD Disclosure, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): July 05, 2024 IGM Biosciences, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-39045 77-0349194 (State or Other Jurisdiction of Incorporation) (Commission Fil

July 3, 2024 SC TO-I/A

SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 AMENDMENT NO. 2 SCHEDULE TO Tender Offer Statement Under Section 14(d)(1) or 13(e)(1) of the Securities Exchange Act of 1934 IGM BIOSCIENCES, INC. (Name of Subject Company (Issuer) and Filing

SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 AMENDMENT NO. 2 TO SCHEDULE TO Tender Offer Statement Under Section 14(d)(1) or 13(e)(1) of the Securities Exchange Act of 1934 IGM BIOSCIENCES, INC. (Name of Subject Company (Issuer) and Filing Person (Offeror)) Options to Purchase Common Stock Covering Common Stock, $0.01 par value (Title of Class of Securities) 449585108 (CUSIP Number of

July 1, 2024 CORRESP

July 1, 2024

Wilson Sonsini Goodrich & Rosati Professional Corporation 139 Townsend Street, Suite 150 San Francisco, CA 94107 O: 415.

July 1, 2024 SC TO-I/A

SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 AMENDMENT NO. 1 SCHEDULE TO Tender Offer Statement Under Section 14(d)(1) or 13(e)(1) of the Securities Exchange Act of 1934 IGM BIOSCIENCES, INC. (Name of Subject Company (Issuer) and Filing

SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 AMENDMENT NO. 1 TO SCHEDULE TO Tender Offer Statement Under Section 14(d)(1) or 13(e)(1) of the Securities Exchange Act of 1934 IGM BIOSCIENCES, INC. (Name of Subject Company (Issuer) and Filing Person (Offeror)) Options to Purchase Common Stock Covering Common Stock, $0.01 par value (Title of Class of Securities) 449585108 (CUSIP Number of

June 20, 2024 EX-99.(A)(1)(C)

Election Terms and Conditions.

Exhibit (a)(1)(C) IGM BIOSCIENCES, INC. OFFER TO EXCHANGE CERTAIN OUTSTANDING OPTIONS FOR RESTRICTED STOCK UNITS ELECTION TERMS AND CONDITIONS THE OFFER EXPIRES AT 9:00 P.M., PACIFIC TIME, ON JULY 18, 2024, UNLESS THE OFFER IS EXTENDED Terms used in this Election Terms & Conditions and Election Instructions attached hereto, that are defined in the Offer to Exchange have the same meaning as those d

June 20, 2024 EX-99.(A)(1)(A)

Offer to Exchange Certain Outstanding Awards for New RSUs, dated June 20, 2024.

Table of Contents Exhibit (a)(1)(A) IGM BIOSCIENCES, INC. OFFER TO EXCHANGE CERTAIN OUTSTANDING OPTIONS FOR RESTRICTED STOCK UNITS This document constitutes part of the prospectus relating to the securities that have been registered under the Securities Act of 1933, as amended. The prospectus relates to the IGM Biosciences, Inc. Amended and Restated 2018 Omnibus Incentive Plan, as amended. June 20

June 20, 2024 EX-FILING FEES

Filing Fee Table

Exhibit 107 Calculation of Filing Fee Tables Schedule TO (Form Type) IGM Biosciences, Inc.

June 20, 2024 EX-99.(A)(1)(D)

Form of Confirmation Email.

Exhibit (a)(1)(D) Form of Confirmation to Eligible Employees To: All Eligible Employees From: info@mail.

June 20, 2024 EX-99.(A)(1)(H)

Employee Script.

Exhibit (a)(1)(H) SLIDE 2 Please take a moment to review the disclaimer on this slide as it relates to the offer to exchange.

June 20, 2024 EX-99.(A)(1)(E)

Form of Reminder Email.

Exhibit (a)(1)(E) FORM OF REMINDER EMAIL To: All Eligible Employees From: info@mail.

June 20, 2024 EX-99.(A)(1)(B)

Launch Announcement.

Exhibit (a)(1)(B) EMAIL TO ALL ELIGIBLE EMPLOYEES From: [email protected] To: All Eligible Employees Date: June 20, 2024 Subject: LAUNCH OF STOCK OPTION EXCHANGE PROGRAM IGM Employees, As previewed by Fred Schwarzer in his email on June 18, 2024, IGM Biosciences, Inc.’s (“IGM”) Board of Directors and stockholders recently approved a voluntary, one-time stock option exchange offer for em

June 20, 2024 EX-99.(A)(1)(G)

Employee Presentation.

Option Exchange Program Education & Information Session Global Leaders in IgM Antibodies TM Begins: Thursday, June 20, 2024 Ends: Thursday, July 18, 2024 at 9pm (PT) Exhibit EXA1G Disclaimer The statements in this presentation concerning the Option Exchange, Eligible Options, the equity incentive plans, and the replacement RSUs are summaries and are not complete descriptions thereof.

June 20, 2024 EX-99.(A)(1)(F)

Screenshots from Offer Website.

Exhibit (a)(1)(F) IGM BIOSCIENCES My Option Exchange Welcome election value calculator resources admin logout infinite equity Welcome Option Exchange Program Commencement Date: June 20, 2024 Expiration Time: July 18, 2024 at 9:00 PM Pacific Time We are offering you the opportunity to exchange some or all of your eligible options, as described in the Offer to Exchange Certain Outstanding Options for Restricted Stock Units (the “Offer to Exchange”), for a number of new restricted stock units (“RSUs”).

June 20, 2024 SC TO-I

SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE TO Tender Offer Statement Under Section 14(d)(1) or 13(e)(1) of the Securities Exchange Act of 1934 IGM BIOSCIENCES, INC. (Name of Subject Company (Issuer) and Filing Person (Offeror)

SC TO-I SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE TO Tender Offer Statement Under Section 14(d)(1) or 13(e)(1) of the Securities Exchange Act of 1934 IGM BIOSCIENCES, INC. (Name of Subject Company (Issuer) and Filing Person (Offeror)) Options to Purchase Common Stock Covering Common Stock, $0.01 par value (Title of Class of Securities) 449585108 (CUSIP Number of Class of S

June 18, 2024 SC TO-C

SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE TO Tender Offer Statement Under Section 14(d)(1) or 13(e)(1) of the Securities Exchange Act of 1934 IGM BIOSCIENCES, INC. (Name of Subject Company (Issuer) and Filing Person (Offeror)

SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE TO Tender Offer Statement Under Section 14(d)(1) or 13(e)(1) of the Securities Exchange Act of 1934 IGM BIOSCIENCES, INC. (Name of Subject Company (Issuer) and Filing Person (Offeror)) Options to Purchase Common Stock Covering Common Stock, $0.01 par value (Title of Class of Securities) 449585108 (CUSIP Number of Class of Securitie

June 18, 2024 EX-99.1

Dear IGM,

Exhibit 99.1 Dear IGM, I am very pleased to be able to pass along some exciting news. Our stockholders and our board of directors have both approved a voluntary Option Exchange Program, which will provide eligible employees a one-time opportunity to exchange certain eligible stock options on a grant-by-grant basis for a lesser amount of restricted stock units (RSUs). Over 96% of the shares present

June 14, 2024 8-K

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits, Submission of Matters to a Vote of Security Holders

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): June 11, 2024 IGM Biosciences, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-39045 77-0349194 (State or Other Jurisdiction of Incorporation) (Commission Fil

June 14, 2024 EX-3.1

Certificate of Amendment to the IGM Biosciences, Inc. Amended and Restated Certificate of Incorporation, as filed with the Secretary of State of the State of Delaware on June 11, 2024

Exhibit 3.1 CERTIFICATE OF AMENDMENT TO THE AMENDED AND RESTATED CERTIFICATE OF INCORPORATION OF IGM BIOSCIENCES, INC. IGM Biosciences, Inc., a corporation organized and existing under the laws of the State of Delaware (the “Corporation”), hereby certifies as follows: 1. The name of the Corporation is IGM Biosciences, Inc. The Corporation was originally incorporated pursuant to the General Corpora

May 8, 2024 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2024 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 0

May 8, 2024 8-K

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): May 08, 2024 IGM Biosciences, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-39045 77-0349194 (State or Other Jurisdiction of Incorporation) (Commission File

May 8, 2024 EX-99.1

IGM Biosciences Announces First Quarter 2024 Financial Results and Provides Corporate Update – Enrollment target exceeded in aplitabart randomized colorectal cancer clinical trial – – Enrollment completed in first dose cohort in imvotamab rheumatoid

Exhibit 99.1 IGM Biosciences Announces First Quarter 2024 Financial Results and Provides Corporate Update – Enrollment target exceeded in aplitabart randomized colorectal cancer clinical trial – – Enrollment completed in first dose cohort in imvotamab rheumatoid arthritis clinical trial – MOUNTAIN VIEW, Calif., May 8, 2024 – IGM Biosciences, Inc. (Nasdaq: IGMS), a clinical-stage biotechnology comp

April 26, 2024 DEFA14A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A PROXY STATEMENT PURSUANT TO SECTION 14(a) OF THE SECURITIES EXCHANGE ACT OF 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A PROXY STATEMENT PURSUANT TO SECTION 14(a) OF THE SECURITIES EXCHANGE ACT OF 1934 Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ☐ Definitive Proxy State

April 26, 2024 DEF 14A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A PROXY STATEMENT PURSUANT TO SECTION 14(a) OF THE SECURITIES EXCHANGE ACT OF 1934

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A PROXY STATEMENT PURSUANT TO SECTION 14(a) OF THE SECURITIES EXCHANGE ACT OF 1934 Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ☒ Defi

April 17, 2024 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): April 17, 2024 IGM Biosciences, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-39045 77-0349194 (State or Other Jurisdiction of Incorporation) (Commission Fi

April 17, 2024 EX-99.1

IGM Biosciences Announces Refocusing of Sanofi Collaboration – Agreement focuses on immunology/inflammation, aligning with Sanofi's ongoing commitment to advancing therapies for patients across multiple inflammatory diseases –

Exhibit 99.1 IGM Biosciences Announces Refocusing of Sanofi Collaboration – Agreement focuses on immunology/inflammation, aligning with Sanofi's ongoing commitment to advancing therapies for patients across multiple inflammatory diseases – MOUNTAIN VIEW, Calif., April 17, 2024 – IGM Biosciences, Inc. (Nasdaq: IGMS), a clinical-stage biotechnology company creating and developing engineered IgM anti

April 15, 2024 PRE 14A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A PROXY STATEMENT PURSUANT TO SECTION 14(a) OF THE SECURITIES EXCHANGE ACT OF 1934

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A PROXY STATEMENT PURSUANT TO SECTION 14(a) OF THE SECURITIES EXCHANGE ACT OF 1934 Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☒ Preliminary Proxy Statement ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ☐ Defi

March 28, 2024 SC 13D/A

IGMS / IGM Biosciences, Inc. / BAKER BROS. ADVISORS LP - SC 13D/A Activist Investment

SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 SCHEDULE 13D (Rule 13d-102) INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT TO RULE 13d-l(a) AND AMENDMENTS THERETO FILED PURSUANT TO RULE 13d-2(a) (Amendment No.

March 7, 2024 S-8

As filed with the Securities and Exchange Commission on March 7, 2024

As filed with the Securities and Exchange Commission on March 7, 2024 Registration No.

March 7, 2024 10-K

Form 10-K

Table of Contents Index to Financial Statements UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.

March 7, 2024 EX-21.1

Subsidiaries of the Registrant

Exhibit 21.1 SUBSIDIARIES OF IGM BIOSCIENCES, INC. Name of Subsidiary Jurisdiction IGM Infectious Diseases, Inc. Delaware IGM Autoimmunity and Inflammation, Inc. Delaware

March 7, 2024 EX-10.12

Outside Director Compensation Policy (as amended and restated on February 26, 2024).

Exhibit 10.12 IGM BIOSCIENCES, INC. OUTSIDE DIRECTOR COMPENSATION POLICY (as Amended and Restated Effective February 26, 2024) IGM Biosciences, Inc. (the “Company”) believes that providing cash and equity compensation to members of the Company’s Board of Directors (the “Board,” and members of the Board, the “Directors”) represents an effective tool to attract, retain and reward Directors who are n

March 7, 2024 EX-97.1

Compensation Recovery Policy.

Exhibit 97.1 IGM BIOSCIENCES, INC. COMPENSATION RECOVERY POLICY As adopted on August 30, 2023 IGM Biosciences, Inc. (the “Company”) is committed to strong corporate governance. As part of this commitment, the Compensation Committee of the Company’s Board of Directors (the “Board”) has adopted this clawback policy called the Compensation Recovery Policy (the “Policy”). The Policy is intended to fur

March 7, 2024 EX-FILING FEES

Filing Fee Table

Exhibit 107 Calculation of Filing Fee Tables Form S-8 (Form Type) IGM BIOSCIENCES, Inc.

March 7, 2024 EX-99.1

IGM Biosciences Announces Fourth Quarter and Full Year 2023 Financial Results and Provides Corporate Update

Exhibit 99.1 IGM Biosciences Announces Fourth Quarter and Full Year 2023 Financial Results and Provides Corporate Update MOUNTAIN VIEW, Calif., Mar. 7, 2024 – IGM Biosciences, Inc. (Nasdaq: IGMS), a clinical-stage biotechnology company creating and developing engineered IgM antibodies, today announced its financial results for the fourth quarter and full year ended December 31, 2023 and provided a

March 7, 2024 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): March 07, 2024 IGM Biosciences, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-39045 77-0349194 (State or Other Jurisdiction of Incorporation) (Commission Fi

March 7, 2024 EX-10.4

Amended and Restated 2019 Employee Stock Purchase Plan, amended October 30, 2023, and forms of agreements thereunder.

Exhibit 10.4 IGM Biosciences, Inc. 2019 EMPLOYEE STOCK PURCHASE PLAN (as amended and restated effective October 30, 2023) 1.Purpose. The purpose of the Plan is to provide employees of the Company and its Designated Companies with an opportunity to purchase Common Stock through accumulated Contributions. The Company intends for the Plan to have two components: a component that is intended to qualif

February 9, 2024 SC 13G/A

IGMS / IGM Biosciences, Inc. / Artal International S.C.A. - SC 13G/A Passive Investment

SC 13G/A 1 d688799dsc13ga.htm SC 13G/A UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934* (Amendment No. 3) IGM Biosciences, Inc. (Name of Issuer) Common Stock, par value $0.01 per share (Title of Class of Securities) 449585108 (CUSIP Number) December 31, 2023 (Date of Event Which Requires Filing of this Statement) Check

January 8, 2024 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): January 08, 2024 IGM Biosciences, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-39045 77-0349194 (State or Other Jurisdiction of Incorporation) (Commission

December 15, 2023 SC 13D/A

IGMS / IGM Biosciences Inc / BAKER BROS. ADVISORS LP - SC 13D/A Activist Investment

SC 13D/A 1 tm2333070d1sc13da.htm SC 13D/A SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 SCHEDULE 13D (Rule 13d-102) INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT TO RULE 13d-l(a) AND AMENDMENTS THERETO FILED PURSUANT TO RULE 13d-2(a) (Amendment No. 6)* IGM Biosciences, Inc. (Name of Issuer) Common stock, par value $0.01 per share (Title of Class of Securities) 449585108 (CUSIP

December 8, 2023 EX-99.1

IGM Biosciences Announces Strategic Pipeline Prioritization and Cash Runway Extension – Priorities: clinical development of DR5 agonist in colorectal cancer and T cell engagers in autoimmune disease – – Plans to file IND for IGM-2644 (CD38 x CD3) to

Exhibit 99.1 IGM Biosciences Announces Strategic Pipeline Prioritization and Cash Runway Extension – Priorities: clinical development of DR5 agonist in colorectal cancer and T cell engagers in autoimmune disease – – Plans to file IND for IGM-2644 (CD38 x CD3) to treat autoimmune disease – – All clinical development in hematologic oncology indications halted – – Cash runway expected to extend into

December 8, 2023 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): December 05, 2023 IGM Biosciences, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-39045 77-0349194 (State or Other Jurisdiction of Incorporation) (Commission

November 15, 2023 CORRESP

IGM Biosciences, Inc. 325 E. Middlefield Road Mountain View, CA 94043

IGM Biosciences, Inc. 325 E. Middlefield Road Mountain View, CA 94043 November 15, 2023 VIA EDGAR U.S. Securities and Exchange Commission Division of Corporation Finance 100 F Street, N.E. Washington, D.C. 20549 Attention: Joshua Gorsky Re: IGM Biosciences, Inc. Registration Statement on Form S-3 File No. 333-275519 Acceleration Request Requested Date: November 17, 2023 Requested Time: 4:00 p.m. L

November 13, 2023 EX-10.1

Amended and Restated 2019 Employee Stock Purchase Plan, amended October 30, 2023, and forms of agreements thereunder

Exhibit 10.1 IGM Biosciences, Inc. 2019 EMPLOYEE STOCK PURCHASE PLAN (as amended and restated effective October 30, 2023) 1.Purpose. The purpose of the Plan is to provide employees of the Company and its Designated Companies with an opportunity to purchase Common Stock through accumulated Contributions. The Company intends for the Plan to have two components: a component that is intended to qualif

November 13, 2023 EX-99.1

IGM Biosciences Announces Third Quarter 2023 Financial Results – Third IND cleared for imvotamab in autoimmune diseases – – International sites opened for aplitabart randomized clinical trial –

Exhibit 99.1 IGM Biosciences Announces Third Quarter 2023 Financial Results – Third IND cleared for imvotamab in autoimmune diseases – – International sites opened for aplitabart randomized clinical trial – MOUNTAIN VIEW, Calif., Nov. 13, 2023 – IGM Biosciences, Inc. (Nasdaq: IGMS), a clinical-stage biotechnology company focused on creating and developing engineered IgM antibodies, today announced

November 13, 2023 EX-FILING FEES

Filing Fee Table

EX-FILING FEES Exhibit 107 CALCULATION OF FILING FEE TABLES Form S-3 (Form Type) IGM Biosciences, Inc.

November 13, 2023 EX-4.3

Form of Indenture

EX-4.3 Exhibit 4.3 IGM BIOSCIENCES, INC. INDENTURE Dated as of , 20 [] Trustee TABLE OF CONTENTS Page ARTICLE I DEFINITIONS AND INCORPORATION BY REFERENCE 1 Section 1.1 Definitions 1 Section 1.2 Other Definitions 4 Section 1.3 Incorporation by Reference of Trust Indenture Act 4 Section 1.4 Rules of Construction 5 ARTICLE II THE SECURITIES 5 Section 2.1 Issuable in Series 5 Section 2.2 Establishmen

November 13, 2023 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): November 13, 2023 IGM Biosciences, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-39045 77-0349194 (State or Other Jurisdiction of Incorporation) (Commission

November 13, 2023 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Numbe

November 13, 2023 S-3

As filed with the Securities and Exchange Commission on November 13, 2023

S-3 Table of Contents As filed with the Securities and Exchange Commission on November 13, 2023 Registration No.

October 3, 2023 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): October 03, 2023 IGM Biosciences, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-39045 77-0349194 (State or Other Jurisdiction of Incorporation) (Commission

October 3, 2023 EX-99.1

IGM Biosciences Announces Retirement of Chairman Michael Loberg, Ph.D. from Board of Directors and Appointment of Elizabeth H.Z. Thompson, Ph.D. to Board of Directors

Exhibit 99.1 IGM Biosciences Announces Retirement of Chairman Michael Loberg, Ph.D. from Board of Directors and Appointment of Elizabeth H.Z. Thompson, Ph.D. to Board of Directors MOUNTAIN VIEW, Calif., Oct. 03, 2023 – IGM Biosciences, Inc. (Nasdaq: IGMS), a clinical-stage biotechnology company focused on creating and developing engineered IgM antibodies, today announced that Michael Loberg, Ph.D.

August 3, 2023 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-39045 IGM Biosci

August 3, 2023 8-K

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): August 03, 2023 IGM Biosciences, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-39045 77-0349194 (State or Other Jurisdiction of Incorporation) (Commission F

August 3, 2023 EX-99.1

IGM Biosciences Announces Second Quarter 2023 Financial Results – Continued progress in clinical development across portfolio – – Public equity offering and concurrent private placement with gross proceeds of $120.0 million –

Exhibit 99.1 IGM Biosciences Announces Second Quarter 2023 Financial Results – Continued progress in clinical development across portfolio – – Public equity offering and concurrent private placement with gross proceeds of $120.0 million – MOUNTAIN VIEW, Calif., August 3, 2023 – IGM Biosciences, Inc. (Nasdaq: IGMS), a clinical-stage biotechnology company focused on creating and developing engineere

August 3, 2023 EX-10.3

Amended and Restated Change in Control and Severance Policy.

Exhibit 10.3 IGM BIOSCIENCES, Inc. Amended and restated Change in Control and Severance Policy (Adopted on August 7, 2019, Amended and Restated on April 24, 2023) This Amended and Restated Change in Control and Severance Policy (the “Policy”) is designed to provide certain protections to a select group of designated key employees of IGM Biosciences, Inc. (“IGM” or the “Company”) or any of its subs

July 19, 2023 EX-99.1

JOINT FILING AGREEMENT

EX-99.1 Exhibit 99.1 JOINT FILING AGREEMENT In accordance with Rule 13d-1(k) under the Securities Exchange Act of 1934, as amended, the undersigned agree to the joint filing with the Securities and Exchange Commission on behalf of each of them of a statement on Schedule 13D (including amendments thereto) with respect to certain shares of the Common Stock of IGM Biosciences, Inc. and further agree

July 19, 2023 SC 13D/A

IGMS / IGM Biosciences Inc / Haldor Topsoe Holding A/S - SC 13D/A Activist Investment

SC 13D/A UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13D Under the Securities Exchange Act of 1934 (Amendment No. 2)* IGM Biosciences, Inc. (Name of Issuer) Common Stock, par value $0.01 per share (Title of Class of Securities) 449585108 (CUSIP Number) Topsøe Holding A/S Haldor Topsøes Allé 1 DK-2800 Kgs. Lyngby Denmark +45 4527 2000 (Name, Address and Telephon

June 28, 2023 SC 13D/A

IGMS / IGM Biosciences Inc / BAKER BROS. ADVISORS LP - SC 13D/A Activist Investment

SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 SCHEDULE 13D (Rule 13d-102) INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT TO RULE 13d-l(a) AND AMENDMENTS THERETO FILED PURSUANT TO RULE 13d-2(a) (Amendment No.

June 28, 2023 SC 13D/A

IGMS / IGM Biosciences Inc / Redmile Group, LLC - SC 13D/A Activist Investment

UNITED STATES SECURITIES & EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13D Under the Securities Exchange Act of 1934 (Amendment No. 6)* IGM Biosciences, Inc. (Name of Issuer) Common Stock, $0.01 par value per share (Title of Class of Securities) 449585108 (CUSIP Number) Redmile Group, LLC Attn: Jennifer Ciresi One Letterman Drive, Bldg D, Ste D3-300 San Francisco, CA 94129 (415) 489-9980 (

June 27, 2023 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): June 23, 2023 IGM Biosciences, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-39045 77-0349194 (State or Other Jurisdiction of Incorporation) (Commission Fil

June 27, 2023 EX-10.1

Amended and Restated 2018 Omnibus Incentive Plan of IGM Biosciences, Inc. and forms of agreements thereunder (incorporated by reference from Exhibit10.1 to IGM’s Current Report on Form 8-K filed with the Securities and Exchange Commission on June 27, 2023).

Exhibit 10.1 IGM BIOSCIENCES, INC. AMENDED AND RESTATED 2018 OMNIBUS INCENTIVE PLAN (as amended and restated effective June 23, 2023) 1. Purposes of the Plan. The purposes of this Plan are: • to attract and retain the best available personnel for positions of substantial responsibility, • to provide additional incentive to Employees, Directors and Consultants, and • to promote the success of the C

June 23, 2023 EX-1.1

Underwriting Agreement, dated as of June 22, 2023, among IGM Biosciences, Inc. and the Representatives

EX-1.1 Exhibit 1.1 1,597,827 Shares of Common Stock 9,000,000 Shares of Non-Voting Common Stock IGM Biosciences, Inc. UNDERWRITING AGREEMENT June 22, 2023 BOFA SECURITIES, INC. JEFFERIES LLC STIFEL, NICOLAUS & COMPANY, INCORPORATED GUGGENHEIM SECURITIES, LLC As Representatives of the several Underwriters c/o BOFA SECURITIES, INC. One Bryant Park New York, New York 10036 c/o JEFFERIES LLC 520 Madis

June 23, 2023 EX-10.1

Common Stock Purchase Agreement, dated as of June 22, 2023, between the Registrant and RedCo II Master Fund, L.P.

EX-10.1 Exhibit 10.1 COMMON STOCK PURCHASE AGREEMENT This COMMON STOCK PURCHASE AGREEMENT (the “Agreement”), dated as of June 22, 2023, is entered into by and between IGM Biosciences, Inc., a Delaware corporation (the “Company”), and the buyers listed on the Schedule of Buyers attached hereto as Exhibit A, as may be updated in accordance with Section 9(g) (individually, together with its permitted

June 23, 2023 424B5

1,597,827 Shares of Common Stock 9,000,000 Shares of Non-Voting Common Stock

424B5 Table of Contents Filed Pursuant to Rule 424(b)(5) Registration No. 333-268136 Prospectus Supplement (To Prospectus Dated November 14, 2022) 1,597,827 Shares of Common Stock 9,000,000 Shares of Non-Voting Common Stock We are offering 1,597,827 shares of our common stock and 9,000,000 shares of our non-voting common stock in this offering. This prospectus supplement also relates to the offeri

June 23, 2023 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) June 22, 2023 IGM Biosciences, Inc

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) June 22, 2023 IGM Biosciences, Inc. (Exact name of registrant as specified in its charter) Delaware 001-39045 77-0349194 (State or other jurisdiction of incorporation) (Commission File

June 22, 2023 424B5

Subject to completion, dated June 21, 2023

424B5 Table of Contents Filed Pursuant to Rule 424(b)(5) Registration No. 333-268136 The information in this preliminary prospectus supplement and the accompanying prospectus is not complete and may be changed. A registration statement relating to these securities has been declared effective by the Securities and Exchange Commission. This preliminary prospectus supplement and the accompanying pros

June 22, 2023 FWP

IGM Announces Pricing of $107.3 Million Upsized Public Offering and Concurrent Private Placement

FWP Free Writing Prospectus pursuant to Rule 433 dated June 22, 2023 Relating to the Preliminary Prospectus Supplement dated June 21, 2023 Registration Statement No.

June 22, 2023 FWP

IGM Announces Proposed Public Offering and Concurrent Private Placement

FWP Free Writing Prospectus pursuant to Rule 433 dated June 21, 2023 Registration Statement No.

June 21, 2023 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): June 2, 2023 IGM Biosciences, Inc

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): June 2, 2023 IGM Biosciences, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-39045 77-0349194 (State or Other Jurisdiction of Incorporation) (Commission File

June 21, 2023 EX-99.1

– Additional data from Phase 1 combination with FOLFIRI continues to show encouraging activity in median third-line metastatic colorectal cancer patients – – Progression-free survival of 5.6 months in median third-line colorectal cancer patients with

EX-99.1 Exhibit 99.1 IGM Biosciences Announces Update on IGM-8444 Phase 1 Trial and Future Clinical Development June 2, 2023 – Additional data from Phase 1 combination with FOLFIRI continues to show encouraging activity in median third-line metastatic colorectal cancer patients – – Progression-free survival of 5.6 months in median third-line colorectal cancer patients without bevacizumab – – Promi

June 13, 2023 SC 13D/A

IGMS / IGM Biosciences Inc / Redmile Group, LLC - SC 13D/A Activist Investment

UNITED STATES SECURITIES & EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13D Under the Securities Exchange Act of 1934 (Amendment No. 5)* IGM Biosciences, Inc. (Name of Issuer) Common Stock, $0.01 par value per share (Title of Class of Securities) 449585108 (CUSIP Number) Redmile Group, LLC Attn: Jennifer Ciresi One Letterman Drive, Bldg D, Ste D3-300 San Francisco, CA 94129 (415) 489-9980 (

May 12, 2023 EX-99.1

IGM Biosciences Announces First Quarter 2023 Financial Results and Provides Corporate Update – Randomized clinical trial of IGM-8444 plus FOLFIRI and bevacizumab in second line metastatic colorectal cancer underway – – Plans to present additional non

Exhibit 99.1 IGM Biosciences Announces First Quarter 2023 Financial Results and Provides Corporate Update – Randomized clinical trial of IGM-8444 plus FOLFIRI and bevacizumab in second line metastatic colorectal cancer underway – – Plans to present additional non-randomized clinical data for 3 mg/kg of IGM-8444 plus FOLFIRI, with and without bevacizumab, in the middle of 2023 – – Plans to begin cl

May 12, 2023 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-39045 IGM Biosc

May 12, 2023 8-K

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): May 12, 2023 IGM Biosciences, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-39045 77-0349194 (State or Other Jurisdiction of Incorporation) (Commission File

April 27, 2023 DEF 14A

Schedule 14A

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A PROXY STATEMENT PURSUANT TO SECTION 14(a) OF THE SECURITIES EXCHANGE ACT OF 1934 Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ☒ Defi

April 27, 2023 DEFA14A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A PROXY STATEMENT PURSUANT TO SECTION 14(a) OF THE SECURITIES EXCHANGE ACT OF 1934

DEFA14A 1 noticeandaccessmateri.htm DEFA14A UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A PROXY STATEMENT PURSUANT TO SECTION 14(a) OF THE SECURITIES EXCHANGE ACT OF 1934 Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement ☐ Confidential, for Use of the Commission Only (as permitted b

March 30, 2023 S-8

As filed with the Securities and Exchange Commission on March 30, 2023

As filed with the Securities and Exchange Commission on March 30, 2023 Registration No.

March 30, 2023 8-K

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): March 30, 2023 IGM Biosciences, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-39045 77-0349194 (State or Other Jurisdiction of Incorporation) (Commission Fi

March 30, 2023 EX-21

Subsidiaries of the Registrant

Exhibit 21.1 SUBSIDIARIES OF IGM BIOSCIENCES, INC. Name of Subsidiary Jurisdiction IGM Infectious Diseases, Inc. Delaware IGM Autoimmunity and Inflammation, Inc. Delaware

March 30, 2023 EX-FILING FEES

Filing Fee Table

Exhibit 107 Calculation of Filing Fee Tables Form S-8 (Form Type) IGM BIOSCIENCES, Inc.

March 30, 2023 EX-99

IGM Biosciences Announces Fourth Quarter and Full Year 2022 Financial Results and Provides Corporate Update – Encouraging initial data from IGM-8444 combination with FOLFIRI; first patient dosed in randomized trial – – Imvotamab to move forward into

Exhibit 99.1 IGM Biosciences Announces Fourth Quarter and Full Year 2022 Financial Results and Provides Corporate Update – Encouraging initial data from IGM-8444 combination with FOLFIRI; first patient dosed in randomized trial – – Imvotamab to move forward into clinical studies in multiple autoimmune diseases – – Initiation of Phase 1 clinical trial for targeted immunostimulatory IL-15 cytokine I

March 30, 2023 EX-10

Outside Director Compensation Policy (as amended and restated on March 16, 2023)

Exhibit 10.13 IGM BIOSCIENCES, INC. OUTSIDE DIRECTOR COMPENSATION POLICY (as Amended and Restated Effective March 16, 2023) IGM Biosciences, Inc. (the “Company”) believes that providing cash and equity compensation to members of the Company’s Board of Directors (the “Board,” and members of the Board, the “Directors”) represents an effective tool to attract, retain and reward Directors who are not

March 30, 2023 10-K

Form 10-K

Table of Contents Index to Financial Statements UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.

March 30, 2023 EX-10

Amended and Restated 2019 Employee Stock Purchase Plan, amended May 1, 2022, and forms of agreements thereunder.

Exhibit 10.4 IGM Biosciences, Inc. 2019 EMPLOYEE STOCK PURCHASE PLAN (as amended and restated effective May 1, 2022) 1.Purpose. The purpose of the Plan is to provide employees of the Company and its Designated Companies with an opportunity to purchase Common Stock through accumulated Contributions. The Company intends for the Plan to have two components: a component that is intended to qualify as

March 21, 2023 8-K

Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): March 16, 2023 IGM Biosciences, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-39045 77-0349194 (State or Other Jurisdiction of Incorporation) (Commission Fi

March 21, 2023 EX-3

Amended and Restated Bylaws of the Registrant

Exhibit 3.1 AMENDED AND RESTATED BYLAWS OF IGM BIOSCIENCES, INC. (As amended and restated on March 16, 2023) TABLE OF CONTENTS (continued) Page TABLE OF CONTENTS Page ARTICLE I - CORPORATE OFFICES 1 1.1 REGISTERED OFFICE 1 1.2 OTHER OFFICES 1 ARTICLE II - MEETINGS OF STOCKHOLDERS 1 2.1 PLACE OF MEETINGS 1 2.2 ANNUAL MEETING 1 2.3 SPECIAL MEETING 1 2.4 ADVANCE NOTICE PROCEDURES 2 2.5 NOTICE OF STOC

March 10, 2023 8-K

Regulation FD Disclosure

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): March 10, 2023 IGM Biosciences, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-39045 77-0349194 (State or Other Jurisdiction of Incorporation) (Commission Fi

February 13, 2023 SC 13G/A

IGMS / IGM Biosciences Inc / Artal International S.C.A. - SC 13G/A Passive Investment

SC 13G/A 1 d374452dsc13ga.htm SC 13G/A UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934* (Amendment No. 2) IGM Biosciences, Inc. (Name of Issuer) Common Stock, par value $0.01 per share (Title of Class of Securities) 449585108 (CUSIP Number) December 31. 2022 (Date of Event Which Requires Filing of this Statement) Check

January 6, 2023 8-K

Financial Statements and Exhibits, Results of Operations and Financial Condition, Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): January 06, 2023 IGM Biosciences, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-39045 77-0349194 (State or Other Jurisdiction of Incorporation) (Commission

January 6, 2023 EX-99.1

Forward-looking statements . This presentation contains “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995. These forward-looking statements reflect the current views of the management of IGM Biosc

Corporate Overview January 6, 2023 Global Leaders in IgM Antibodies Exhibit 99.1 Igm biosciences? REIMAGINING antibody medicines Forward-looking statements . This presentation contains ?forward-looking statements? within the meaning of the Private Securities Litigation Reform Act of 1995. These forward-looking statements reflect the current views of the management of IGM Biosciences, Inc. (the ?Co

November 9, 2022 CORRESP

November 9, 2022

CORRESP 1 filename1.htm 325 E Middlefield Road Mountain View, CA 94043 (650) 965-7873 November 9, 2022 VIA EDGAR U.S. Securities and Exchange Commission Division of Corporation Finance Office of Healthcare & Insurance 100 F Street, N.E. Washington, D.C. 20549-3720 Attention: Jimmy McNamara Re: IGM Biosciences, Inc. Registration Statement on Form S-3 File No. 333-268136 Acceleration Request Request

November 3, 2022 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2022 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-39045 IGM Biosciences, Inc.

November 3, 2022 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): November 03, 2022 IGM Biosciences, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-39045 77-0349194 (State or Other Jurisdiction of Incorporation) (Commission

November 3, 2022 EX-4.3

Form of Indenture

EX-4.3 Exhibit 4.3 IGM BIOSCIENCES, INC. INDENTURE Dated as of , 20 [ ] Trustee TABLE OF CONTENTS Page ARTICLE I DEFINITIONS AND INCORPORATION BY REFERENCE 1 Section 1.1 Definitions 1 Section 1.2 Other Definitions 4 Section 1.3 Incorporation by Reference of Trust Indenture Act 5 Section 1.4 Rules of Construction 5 ARTICLE II THE SECURITIES 5 Section 2.1 Issuable in Series 5 Section 2.2 Establishme

November 3, 2022 S-3

Power of Attorney (included on the signature page to this Registration Statement)

S-3 1 d412010ds3.htm S-3 Table of Contents As filed with the Securities and Exchange Commission on November 3, 2022 Registration No. 333- UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM S-3 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 IGM Biosciences, Inc. (Exact name of registrant as specified in its charter) Delaware 77-0349194 (State or other jurisdiction

November 3, 2022 EX-FILING FEES

Filing Fee Table

Exhibit 107 Calculation of Filing Fee Tables Form S-3 (Form Type) IGM BIOSCIENCES, Inc.

November 3, 2022 EX-99.1

IGM Biosciences Announces Third Quarter 2022 Financial Results and Provides Corporate Update – Data from T cell Engager Portfolio for Hematologic Malignancies, Including First Preclinical Data for IGM-2644 and IGM-2537, Selected for Poster Presentati

Exhibit 99.1 IGM Biosciences Announces Third Quarter 2022 Financial Results and Provides Corporate Update – Data from T cell Engager Portfolio for Hematologic Malignancies, Including First Preclinical Data for IGM-2644 and IGM-2537, Selected for Poster Presentations at 2022 ASH Annual Meeting – – Data Update from Phase 1 Trial of Imvotamab Demonstrates Durable Benefit for R/R NHL Patients, with 7/

October 5, 2022 SC 13D/A

IGMS / IGM Biosciences Inc / Redmile Group, LLC - SC 13D/A Activist Investment

UNITED STATES SECURITIES& EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13D Under the Securities Exchange Act of 1934 (Amendment No. 4)* IGM Biosciences, Inc. (Name of Issuer) Common Stock, $0.01 par value per share (Title of Class of Securities) 449585108 (CUSIP Number) Redmile Group, LLC Attn: Jennifer Ciresi One Letterman Drive, Bldg D, Ste D3-300 San Francisco, CA 94129 (415) 489-9980 (N

August 8, 2022 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 FORM 10-Q (Mark One) ? QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2022 OR ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-39045 IGM Biosciences, Inc.

August 8, 2022 8-K

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): August 08, 2022 IGM Biosciences, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-39045 77-0349194 (State or Other Jurisdiction of Incorporation) (Commission F

August 8, 2022 EX-99.1

IGM Biosciences Announces Second Quarter 2022 Financial Results and Provides Corporate Update – Continued Advancement in Clinical Development of Imvotamab (IGM-2323) and IGM-8444 – – Received $150 Million Upfront Payment in Connection with Closing of

Exhibit 99.1 IGM Biosciences Announces Second Quarter 2022 Financial Results and Provides Corporate Update ? Continued Advancement in Clinical Development of Imvotamab (IGM-2323) and IGM-8444 ? ? Received $150 Million Upfront Payment in Connection with Closing of Collaboration Agreement with Sanofi ? MOUNTAIN VIEW, Calif., August 08, 2022 ? IGM Biosciences, Inc. (Nasdaq: IGMS), a clinical-stage bi

August 8, 2022 424B3

24,747,658 SHARES IGM Biosciences, Inc. Common Stock

Table of Contents Filed Pursuant to Rule 424(b)(3) Registration No. 333-258641 PROSPECTUS 24,747,658 SHARES IGM Biosciences, Inc. Common Stock This prospectus relates to the sale or other disposition from time to time by the selling stockholders named in this prospectus of up to an aggregate of 24,747,658 shares of the common stock of IGM Biosciences, Inc., which includes 6,431,205 shares of our c

June 24, 2022 8-K

Submission of Matters to a Vote of Security Holders

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) June 21, 2022 IGM Biosciences, Inc. (Exact name of registrant as specified in its charter) Delaware 001-39045 77-0349194 (State or other jurisdiction of incorporation) (Commission File

June 1, 2022 8-K

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) May 25, 2022 IGM Biosciences, Inc. (Exact name of registrant as specified in its charter) Delaware 001-39045 77-0349194 (State or other jurisdiction of incorporation) (Commission File

May 9, 2022 EX-10.2

Amended and Restated 2019 Employee Stock Purchase Plan, amended May 1, 2022, and forms of agreements thereunder.

Exhibit 10.2 IGM Biosciences, Inc. 2019 EMPLOYEE STOCK PURCHASE PLAN (as amended and restated effective May 1, 2022) 1.Purpose. The purpose of the Plan is to provide employees of the Company and its Designated Companies with an opportunity to purchase Common Stock through accumulated Contributions. The Company intends for the Plan to have two components: a component that is intended to qualify as

May 9, 2022 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 FORM 10-Q (Mark One) ? QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2022 OR ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-39045 IGM Biosciences, Inc.

May 9, 2022 EX-99.1

IGM Biosciences Announces First Quarter 2022 Financial Results and Provides Corporate Update – Closing of Global Collaboration Agreement with Sanofi; $150 Million Upfront Payment to IGM – – Completed Public Equity Offering with Gross Proceeds of $230

Exhibit 99.1 IGM Biosciences Announces First Quarter 2022 Financial Results and Provides Corporate Update ? Closing of Global Collaboration Agreement with Sanofi; $150 Million Upfront Payment to IGM ? ? Completed Public Equity Offering with Gross Proceeds of $230 Million ? ? Continued Advancement in Clinical Development of IGM-2323 and IGM-8444 ? MOUNTAIN VIEW, Calif., May 09, 2022 ? IGM Bioscienc

May 9, 2022 8-K

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) May 9, 2022 IGM Biosciences, Inc. (Exact name of registrant as specified in its charter) Delaware 001-39045 77-0349194 (State or other jurisdiction of incorporation) (Commission File N

April 27, 2022 DEF 14A

Schedule 14A,

DEF 14A 1 d297791ddef14a.htm DEFINITIVE PROXY STATEMENT Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A PROXY STATEMENT PURSUANT TO SECTION 14(a) OF THE SECURITIES EXCHANGE ACT OF 1934 Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement ☐ Confidential, for Use of the C

April 27, 2022 DEFA14A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A PROXY STATEMENT PURSUANT TO SECTION 14(a) OF THE SECURITIES EXCHANGE ACT OF 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A PROXY STATEMENT PURSUANT TO SECTION 14(a) OF THE SECURITIES EXCHANGE ACT OF 1934 Filed by the Registrant ? Filed by a Party other than the Registrant ? Check the appropriate box: ? Preliminary Proxy Statement ? Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ? Definitive Proxy State

April 5, 2022 SC 13D/A

IGMS / IGM Biosciences Inc / Redmile Group, LLC - SC 13D/A Activist Investment

UNITED STATES SECURITIES & EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13D Under the Securities Exchange Act of 1934 (Amendment No. 3)* IGM Biosciences, Inc. (Name of Issuer) Common Stock, $0.01 par value per share (Title of Class of Securities) 449585108 (CUSIP Number) Redmile Group, LLC Jeremy C. Green One Letterman Drive, Bldg D, Ste D3-300 San Francisco, CA 94129 Attention: Legal Depar

April 5, 2022 EX-99.2

IGM BIOSCIENCES, INC. registration rights waiver

Exhibit 99.2 IGM BIOSCIENCES, INC. registration rights waiver WHEREAS, pursuant to that certain Amended and Restated Investor Rights Agreement, by and between IGM Biosciences, Inc. (the “Company”) and the parties thereto, dated as of June 28, 2019 (the “IRA”), the Investors (as defined in the IRA) have certain registration rights. WHEREAS, pursuant to certain Registration Rights Agreements, by and

April 5, 2022 SC 13D/A

IGMS / IGM Biosciences Inc / BAKER BROS. ADVISORS LP - SC 13D/A Activist Investment

SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 SCHEDULE 13D (Rule 13d-102) INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT TO RULE 13d-l(a) AND AMENDMENTS THERETO FILED PURSUANT TO RULE 13d-2(a) (Amendment No.

March 30, 2022 8-K

Entry into a Material Definitive Agreement, Financial Statements and Exhibits, Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) March 29, 2022 IGM Biosciences, Inc. (Exact name of registrant as specified in its charter) Delaware 001-39045 77-0349194 (State or other jurisdiction of incorporation) (Commission Fil

March 30, 2022 EX-99.1

IGM Announces Proposed Public Offering

Exhibit 99.1 IGM Announces Proposed Public Offering March 29, 2022 MOUNTAIN VIEW, Calif., March 29, 2022 (GLOBE NEWSWIRE) ? IGM Biosciences, Inc. (NASDAQ: IGMS) today announced that it intends to offer and sell $200.0 million of shares of its common stock and, in lieu of common stock to certain investors that so choose, non-voting common stock, in an underwritten public offering. In addition, IGM

March 30, 2022 EX-1.1

Director Lock-Up Agreement, by and among Felix Baker, J.P. Morgan Securities LLC, BofA Securities, Inc., Stifel, Nicolaus & Company, Incorporated, and Guggenheim Securities, LLC (incorporated by reference to Exhibit A to Exhibit 1.1 to the Issuer’s Current Report on Form 8-K (SEC File No. 001-39045), filed with the SEC on March 30, 2022).

Exhibit 1.1 EXECUTION VERSION 8,695,653 Shares of Non-Voting Common Stock IGM Biosciences, Inc. UNDERWRITING AGREEMENT March 29, 2022 J.P. MORGAN SECURITIES LLC BOFA SECURITIES, INC. STIFEL, NICOLAUS & COMPANY, INCORPORATED GUGGENHEIM SECURITIES, LLC As Representatives of the several Underwriters c/o J.P. MORGAN SECURITIES LLC 383 Madison Avenue New York, New York 10179 c/o BOFA SECURITIES, INC. O

March 30, 2022 424B5

8,695,653 Shares of Non-Voting Common Stock

424B5 1 d336902d424b5.htm 424B5 Table of Contents Filed Pursuant to Rule 424(b)(5) Registration No. 333-258644 Prospectus Supplement (To Prospectus Dated August 19, 2021) 8,695,653 Shares of Non-Voting Common Stock We are offering 8,695,653 shares of our non-voting common stock in this offering. This prospectus supplement also relates to the offering of the shares of our voting common stock issuab

March 30, 2022 EX-99.2

IGM Announces Pricing of $200.0 Million Public Offering

Exhibit 99.2 IGM Announces Pricing of $200.0 Million Public Offering March 30, 2022 MOUNTAIN VIEW, Calif., March 30, 2022 (GLOBE NEWSWIRE) ? IGM Biosciences, Inc. (NASDAQ: IGMS) today announced the pricing of its underwritten public offering of 8,695,653 shares of its non-voting common stock at a price to the public of $23.00 per share. IGM expects to receive total gross proceeds of approximately

March 29, 2022 EX-10.1

Collaboration and License Agreement by and between IGM Biosciences, Inc. and Genzyme Corporation, dated March 28, 2022.

Exhibit 10.1 Execution Version Confidential CERTAIN INFORMATION HAS BEEN EXCLUDED FROM THIS EXHIBIT BECAUSE IT IS BOTH NOT MATERIAL AND WOULD LIKELY CAUSE COMPETITIVE HARM TO THE REGISTRANT IF PUBLICLY DISCLOSED. OMISSIONS ARE DESIGNATED AS [***]. COLLABORATION AND LICENSE AGREEMENT by and between IGM BIOSCIENCES, INC. and GENZYME CORPORATION dated as of March 28, 2022 TABLE OF CONTENTS ARTICLE 1

March 29, 2022 8-K

Entry into a Material Definitive Agreement, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): March 28, 2022 IGM Biosciences, Inc. (Exact name of registrant as specified in its charter) Delaware 001-39045 77-0349194 (State or other jurisdiction of incorporation) (Commission Fi

March 29, 2022 FWP

-2-

FWP 1 d341937dfwp.htm FWP Free Writing Prospectus dated March 29, 2022 Filed pursuant to Rule 433 under the Securities Act of 1933, as amended Relating to the Preliminary Prospectus Supplement dated March 29, 2022 Registration Statement No. 333-258644 IGM Biosciences, Inc. has filed a registration statement (including a prospectus) and a preliminary prospectus supplement dated March 29, 2022 (the

March 29, 2022 EX-99.1

IGM Biosciences Announces Fourth Quarter and Full Year 2021 Financial Results and Provides Corporate Update – Announced Global Collaboration Agreement with Sanofi for Oncology, Autoimmune and Inflammation Targets; IGM to Receive $150 Million Upfront

EX-99.1 Exhibit 99.1 IGM Biosciences Announces Fourth Quarter and Full Year 2021 Financial Results and Provides Corporate Update – Announced Global Collaboration Agreement with Sanofi for Oncology, Autoimmune and Inflammation Targets; IGM to Receive $150 Million Upfront Payment and potentially more than $6 Billion in Aggregate Development, Regulatory and Commercial Milestones – – Ongoing Progress

March 29, 2022 8-K

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) March 29, 2022 IGM Biosciences, Inc. (Exact name of registrant as specified in its charter) Delaware 001-39045 77-0349194 (State or other jurisdiction of incorporation) (Commission Fil

March 29, 2022 EX-10.15

Outside Director Compensation Policy (as amended and restated on February 7, 2022).

Exhibit 10.15 IGM BIOSCIENCES, INC. OUTSIDE DIRECTOR COMPENSATION POLICY (as Amended and Restated Effective February 7, 2022) IGM Biosciences, Inc. (the ?Company?) believes that providing cash and equity compensation to members of the Company?s Board of Directors (the ?Board,? and members of the Board, the ?Directors?) represents an effective tool to attract, retain and reward Directors who are no

March 29, 2022 S-8

As filed with the Securities and Exchange Commission on March 29, 2022

As filed with the Securities and Exchange Commission on March 29, 2022 Registration No.

March 29, 2022 EX-4.3

Description of Securities

Exhibit 4.3 DESCRIPTION OF SECURITIES Description of Capital Stock The following descriptions of our capital stock and certain provisions of our amended and restated certificate of incorporation and amended and restated bylaws are summaries and are qualified by reference to our amended and restated certificate of incorporation and amended and restated bylaws. Copies of these documents were filed w

March 29, 2022 EX-FILING FEES

Filing Fee Table

Exhibit 107 Calculation of Filing Fee Tables Form S-8 (Form Type) IGM BIOSCIENCES, Inc.

March 29, 2022 10-K

mar UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K

Table of Contents Index to Financial Statements mar UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.

March 29, 2022 EX-21.1

Subsidiaries of the Registrant

Exhibit 21.1 SUBSIDIARIES OF IGM BIOSCIENCES, INC. Name of Subsidiary Jurisdiction IGM Infectious Diseases, Inc. Delaware IGM Autoimmunity and Inflammation, Inc. Delaware

March 29, 2022 424B5

Subject to completion, dated March 29, 2022

Table of Contents Filed Pursuant to Rule 424(b)(5) Registration No. 333-258644 The information in this preliminary prospectus supplement and the accompanying prospectus is not complete and may be changed. A registration statement relating to these securities has been declared effective by the Securities and Exchange Commission. This preliminary prospectus supplement and the accompanying prospectus

February 11, 2022 SC 13G/A

IGMS / IGM Biosciences Inc / Artal International S.C.A. - SC 13G/A Passive Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934* (Amendment No. 1) IGM Biosciences, Inc. (Name of Issuer) Common Stock, par value $0.01 per share (Title of Class of Securities) 449585108 (CUSIP Number) December 31. 2021 (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the ru

January 12, 2022 EX-99.1

IGM Biosciences, Inc. Financial Information

Exhibit 99.1 IGM Biosciences, Inc. Financial Information $230 million cash and investments balance, December 31, 2021 (unaudited)

January 12, 2022 8-K

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) January 12, 2022 IGM Biosciences, Inc. (Exact name of registrant as specified in its charter) Delaware 001-39045 77-0349194 (State or other jurisdiction of incorporation) (Commission F

November 4, 2021 8-K

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) November 4, 2021 IGM Biosciences, Inc. (Exact name of registrant as specified in its charter) Delaware 001-39045 77-0349194 (State or other jurisdiction of incorporation) (Commission F

November 4, 2021 EX-99.1

IGM Biosciences Announces Third Quarter 2021 Financial Results and Provides Corporate Update – Plans to Initiate Phase 2 Studies of IGM-2323 in Diffuse Large B-cell Lymphoma and Follicular Lymphoma – – Data from IGM-2323 Selected for Oral Presentatio

Exhibit 99.1 IGM Biosciences Announces Third Quarter 2021 Financial Results and Provides Corporate Update ? Plans to Initiate Phase 2 Studies of IGM-2323 in Diffuse Large B-cell Lymphoma and Follicular Lymphoma ? ? Data from IGM-2323 Selected for Oral Presentation at 2021 ASH Annual Meeting ? ? IGM-8444 Successfully Completes Phase 1 Monotherapy Dose Escalation ? ? IGM-8444 Showed No Clinically Si

November 4, 2021 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2021 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-39045 IGM Biosciences, Inc.

November 4, 2021 EX-10.1

Outside Director Compensation Policy (as amended and restated on September 24, 2021)

Exhibit 10.1 IGM BIOSCIENCES, INC. OUTSIDE DIRECTOR COMPENSATION POLICY (as Amended and Restated Effective September 24, 2021) IGM Biosciences, Inc. (the ?Company?) believes that providing cash and equity compensation to members of the Company?s Board of Directors (the ?Board,? and members of the Board, the ?Directors?) represents an effective tool to attract, retain and reward Directors who are n

September 27, 2021 SC 13G

IGMS / IGM Biosciences Inc / Artal International S.C.A. - SC 13G Passive Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934* (Amendment No. ) IGM Biosciences, Inc. (Name of Issuer) Common Stock, par value $0.01 per share (Title of Class of Securities) 449585108 (CUSIP Number) September 16, 2021 (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the ru

September 27, 2021 EX-99.1

JOINT FILING AGREEMENT

EXHIBIT 1 JOINT FILING AGREEMENT The undersigned agree that the statement on Schedule 13G with respect to the common stock, $0.

August 17, 2021 CORRESP

August 17, 2021

Wilson Sonsini Goodrich & Rosati Professional Corporation 650 Page Mill Road Palo Alto, California 94304-1050 O: 650.

August 17, 2021 CORRESP

August 17, 2021

CORRESP 1 filename1.htm Wilson Sonsini Goodrich & Rosati Professional Corporation 650 Page Mill Road Palo Alto, California 94304-1050 O: 650.493.9300 F: 650.493.6811 August 17, 2021 VIA EDGAR U.S. Securities and Exchange Commission Division of Corporation Finance Office of Healthcare & Insurance 100 F Street, N.E. Washington, D.C. 20549-3720 Attention: Alan Campbell Re: IGM Biosciences, Inc. Regis

August 9, 2021 EX-99.1

IGM Biosciences Announces Second Quarter 2021 Financial Results and Provides Corporate Update – Recommended Phase 2 Dose of IGM-2323 Expected in 2021 – – Initial Data from Phase 1 Trial of IGM-8444 in Solid Cancers Expected in 2021 – – Expansion of I

EX-99.1 Exhibit 99.1 IGM Biosciences Announces Second Quarter 2021 Financial Results and Provides Corporate Update – Recommended Phase 2 Dose of IGM-2323 Expected in 2021 – – Initial Data from Phase 1 Trial of IGM-8444 in Solid Cancers Expected in 2021 – – Expansion of IgM Platform into Infectious Diseases – MOUNTAIN VIEW, Calif., August 9, 2021 – IGM Biosciences, Inc. (Nasdaq: IGMS), a clinical-s

August 9, 2021 EX-4.2

Form of Indenture, to be entered into between the Registrant and the trustee designated therein.

Exhibit 4.2 IGM BIOSCIENCES, INC. [TRUSTEE], AS TRUSTEE TO INDENTURE DATED AS OF [?] DEBT SECURITIES TABLE OF CONTENTS Page ARTICLE 1 DEFINITIONS AND OTHER PROVISIONS OF GENERAL APPLICATION 1 Section 1.1 Definitions 1 Section 1.2 Compliance Certificates and Opinions 6 Section 1.3 Form of Documents Delivered to Trustee 7 Section 1.4 Acts of Holders; Record Dates 7 Section 1.5 Notices, etc., to Trus

August 9, 2021 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 FORM 10-Q (Mark One) ? QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2021 OR ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-39045 IGM Biosciences, Inc.

August 9, 2021 8-K

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) August 9, 2021 IGM Biosciences, Inc. (Exact name of registrant as specified in its charter) Delaware 001-39045 77-0349194 (State or other jurisdiction of incorporation) (Commission Fil

August 9, 2021 S-3

As filed with the Securities and Exchange Commission on August 9, 2021

Table of Contents As filed with the Securities and Exchange Commission on August 9, 2021 Registration No.

August 9, 2021 S-3

As filed with the Securities and Exchange Commission on August 9, 2021

Table of Contents As filed with the Securities and Exchange Commission on August 9, 2021 Registration No.

August 9, 2021 EX-10.2

Employment Agreement by and between Chris Takimoto and the Registrant, dated as of July 29, 2021

Exhibit 10.2 EMPLOYMENT AGREEMENT This EMPLOYMENT AGREEMENT, dated as of July 29, 2021 is between IGM Biosciences, Inc., a Delaware corporation (the ?Company?) and Chris H. Takimoto (?Executive?). In consideration of the mutual covenants contained herein, the parties agree as follows: 1.Employment; Term of Employment. The Company hereby employs Executive on a date to be confirmed by the Company an

August 9, 2021 EX-3.1

Amended and Restated Certificate of Incorporation of the Registrant, as amended

Exhibit 3.1 AMENDED AND RESTATED CERTIFICATE OF INCORPORATION OF IGM BIOSCIENCES, INC. IGM Biosciences, Inc., a corporation organized and existing under the laws of the State of Delaware (the ?Corporation?), does hereby certify as follows: A. The name of the Corporation is IGM Biosciences, Inc. The Corporation was originally incorporated pursuant to the General Corporation Law of the State of Dela

August 4, 2021 8-K

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) July 29, 2021 IGM Biosciences, Inc. (Exact name of registrant as specified in its charter) Delaware 001-39045 77-0349194 (State or other jurisdiction of incorporation) (Commission File

July 13, 2021 EX-10.1

First Amendment to Lease between IGM Biosciences, Inc. and Real Property Investments, LLC effective July 1, 2021.

Exhibit 10.1 FIRST AMENDMENT TO LEASE This First Amendment to Lease (?First Amendment?), effective as of July 1, 2021, is entered into by and between Real Property Investments, LLC, a Colorado limited liability company (?Landlord?), and IGM Biosciences, Inc., a Delaware corporation (?Tenant?). Any capitalized terms that are used in this First Amendment but not defined herein shall have the meaning

July 13, 2021 8-K

Entry into a Material Definitive Agreement, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) July 7, 2021 IGM Biosciences, Inc. (Exact name of registrant as specified in its charter) Delaware 001-39045 77-0349194 (State or other jurisdiction of incorporation) (Commission File

June 30, 2021 EX-3.1

Certificate of Amendment to Amended and Restated Certificate of Incorporation of IGM Biosciences, Inc.

Exhibit 3.1 CERTIFICATE OF AMENDMENT TO AMENDED AND RESTATED CERTIFICATE OF INCORPORATION OF IGM BIOSCIENCES, INC. IGM Biosciences, Inc., a corporation organized and existing under the laws of the State of Delaware (the ?Corporation?), hereby certifies as follows: A. The name of the Corporation is IGM Biosciences, Inc. The Corporation was originally incorporated pursuant to the General Corporation

June 30, 2021 8-K

Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year, Financial Statements and Exhibits, Submission of Matters to a Vote of Security Holders

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) June 24, 2021 IGM Biosciences, Inc. (Exact name of registrant as specified in its charter) Delaware 001-39045 77-0349194 (State or other jurisdiction of incorporation) (Commission File

May 6, 2021 EX-10.1

Employment Agreement, by and between Lisa Decker and the Registrant, dated as of February 25, 2021.

Exhibit 10.1 EMPLOYMENT AGREEMENT This EMPLOYMENT AGREEMENT, dated as of February 25, 2021 is between IGM Biosciences, Inc., a Delaware corporation (the ?Company?) and Lisa L. Decker (?Executive?). In consideration of the mutual covenants contained herein, the parties agree as follows: 1.Employment; Term of Employment. The Company hereby employs Executive effective as of March 15, 2021 (the ?Effec

May 6, 2021 10-Q

Quarterly Report - 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 FORM 10-Q (Mark One) ? QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2021 OR ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-39045 IGM Biosciences, Inc.

May 6, 2021 EX-10.2

Employment Agreement by and between George Gauthier and the Registrant, dated as of February 10, 2021.

EX-10.2 3 igms-ex102219.htm EX-10.2 Exhibit 10.2 EMPLOYMENT AGREEMENT This EMPLOYMENT AGREEMENT, dated as of February 10, 2021 is between IGM Biosciences, Inc., a Delaware corporation (the “Company”) and George Gauthier (“Executive”). In consideration of the mutual covenants contained herein, the parties agree as follows: 1.Employment; Term of Employment. The Company hereby employs Executive effec

May 6, 2021 8-K

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) May 6, 2021 IGM Biosciences, Inc. (Exact name of registrant as specified in its charter) Delaware 001-39045 77-0349194 (State or other jurisdiction of incorporation) (Commission File N

May 6, 2021 EX-99.1

IGM Biosciences Announces First Quarter 2021 Financial Results and Provides Corporate Update – Recommended Phase 2 Dose of IGM-2323 Expected in 2021 – – Initial Data from Phase 1 Trial of IGM-8444 in Solid Cancers Expected in 2021 – – IND Filing for

EX-99.1 2 d940389dex991.htm EX-99.1 Exhibit 99.1 IGM Biosciences Announces First Quarter 2021 Financial Results and Provides Corporate Update – Recommended Phase 2 Dose of IGM-2323 Expected in 2021 – – Initial Data from Phase 1 Trial of IGM-8444 in Solid Cancers Expected in 2021 – – IND Filing for IGM-7354 Planned in 2021 – MOUNTAIN VIEW, Calif., May 6, 2021 – IGM Biosciences, Inc. (Nasdaq: IGMS),

April 29, 2021 DEFA14A

- DEFINITIVE ADDITIONAL MATERIALS

DEFA14A 1 d147563ddefa14a.htm DEFINITIVE ADDITIONAL MATERIALS UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A PROXY STATEMENT PURSUANT TO SECTION 14(a) OF THE SECURITIES EXCHANGE ACT OF 1934 Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement ☐ Confidential, for Use of the Commission On

April 29, 2021 DEF 14A

Schedule 14A

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A PROXY STATEMENT PURSUANT TO SECTION 14(a) OF THE SECURITIES EXCHANGE ACT OF 1934 Filed by the Registrant ? Filed by a Party other than the Registrant ? Check the appropriate box: ? Preliminary Proxy Statement ? Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ? Defi

April 16, 2021 PRE 14A

- PRELIMINARY PROXY STATEMENT

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A PROXY STATEMENT PURSUANT TO SECTION 14(a) OF THE SECURITIES EXCHANGE ACT OF 1934 Filed by the Registrant ? Filed by a Party other than the Registrant ? Check the appropriate box: ? Preliminary Proxy Statement ? Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ? Defi

March 30, 2021 8-K

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) March 30, 2021 IGM Biosciences, Inc. (Exact name of registrant as specified in its charter) Delaware 001-39045 77-0349194 (State or other jurisdiction of incorporation) (Commission Fil

March 30, 2021 S-8

- REGISTRATION STATEMENT ON FORM S-8

As filed with the Securities and Exchange Commission on March 30, 2021 Registration No.

March 30, 2021 10-K

Annual Report - 10-K

Table of Contents Index to Financial Statements UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.

March 30, 2021 EX-10.12

Outside Director Compensation Policy (as amended and restated on February 19, 2021).

EX-10.12 3 igms-ex1012591.htm EX-10.12 Exhibit 10.12 IGM BIOSCIENCES, INC. OUTSIDE DIRECTOR COMPENSATION POLICY (as Amended and Restated Effective February 19, 2021) IGM Biosciences, Inc. (the “Company”) believes that providing cash and equity compensation to members of the Company’s Board of Directors (the “Board,” and members of the Board, the “Directors”) represents an effective tool to attract

March 30, 2021 EX-4.3

Description of Securities

EX-4.3 2 igms-ex4312.htm EX-4.3 Exhibit 4.3 DESCRIPTION OF SECURITIES Description of Capital Stock The following descriptions of our capital stock and certain provisions of our amended and restated certificate of incorporation and amended and restated bylaws are summaries and are qualified by reference to our amended and restated certificate of incorporation and amended and restated bylaws. Copies

March 30, 2021 EX-99.1

IGM Biosciences Announces Fourth Quarter and Full Year 2020 Financial Results and Provides Corporate Update – Recommended Phase 2 Dose for IGM-2323 Expected in 2021 – – Initial Data from Phase 1 Trial of IGM-8444 in Solid Cancers Expected in 2021 – –

EX-99.1 2 d150404dex991.htm EX-99.1 Exhibit 99.1 IGM Biosciences Announces Fourth Quarter and Full Year 2020 Financial Results and Provides Corporate Update – Recommended Phase 2 Dose for IGM-2323 Expected in 2021 – – Initial Data from Phase 1 Trial of IGM-8444 in Solid Cancers Expected in 2021 – – IND Filing for IGM-7354 Planned in 2021 – – Company to Host Conference Call Today at 4:30 p.m. ET –

January 29, 2021 SC 13D/A

SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 SCHEDULE 13D (Rule 13d-102) INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT TO RULE 13d-l(a) AND AMENDMENTS THERETO FILED PURSUANT TO RULE 13d-2(a) (Amendment No. 3)* IGM Biosciences, In

SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 SCHEDULE 13D (Rule 13d-102) INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT TO RULE 13d-l(a) AND AMENDMENTS THERETO FILED PURSUANT TO RULE 13d-2(a) (Amendment No.

January 28, 2021 8-K

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers - FORM 8-K

Form 8-K UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) January 23, 2021 IGM Biosciences, Inc. (Exact name of registrant as specified in its charter) Delaware 001-39045 77-0349194 (State or other jurisdiction of incorporation) (Com

January 13, 2021 EX-99.1

IGM Biosciences, Inc. Financial Information.

EX-99.1 2 d47680dex991.htm EX-99.1 Exhibit 99.1 IGM Overview Global leaders in the development of engineered IgM antibodies for therapeutic use Lead Programs CD20 x CD3 | Non-Hodgkin’s Lymphoma | Phase 1 in R/R B cell NHL underway DR5 | Solid and Heme Malignancies | Phase 1 in solid tumors & NHL underway IL-15 x PD-L1 | Solid and Heme Malignancies | IND filing: 2021 (anticipated) Proprietary IgM a

January 13, 2021 8-K

Financial Statements and Exhibits, Results of Operations and Financial Condition - 8-K

8-K UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) January 12, 2021 IGM Biosciences, Inc. (Exact name of registrant as specified in its charter) Delaware 001-39045 77-0349194 (State or other jurisdiction of incorporation) (Commissi

January 5, 2021 SC 13D/A

SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 SCHEDULE 13D (Rule 13d-102) INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT TO RULE 13d-l(a) AND AMENDMENTS THERETO FILED PURSUANT TO RULE 13d-2(a) (Amendment No. 2)* IGM Biosciences, In

SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 SCHEDULE 13D (Rule 13d-102) INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT TO RULE 13d-l(a) AND AMENDMENTS THERETO FILED PURSUANT TO RULE 13d-2(a) (Amendment No.

December 16, 2020 EX-99.1

JOINT FILING AGREEMENT

EX-99.1 2 d23170dex991.htm EX-99.1 Exhibit 99.1 JOINT FILING AGREEMENT In accordance with Rule 13d-1(k) under the Securities Exchange Act of 1934, as amended, the undersigned agree to the joint filing with the Securities and Exchange Commission on behalf of each of them of a statement on Schedule 13D (including amendments thereto) with respect to certain shares of the Common Stock of IGM Bioscienc

December 16, 2020 SC 13D/A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13D Under the Securities Exchange Act of 1934 (Amendment No. 1)* IGM Biosciences, Inc. (Name of Issuer) Common Stock, par value $0.01 per share (Title of Class of Securi

SC 13D/A (AMENDMENT NO. 1) UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13D Under the Securities Exchange Act of 1934 (Amendment No. 1)* IGM Biosciences, Inc. (Name of Issuer) Common Stock, par value $0.01 per share (Title of Class of Securities) 449585108 (CUSIP Number) Haldor Topsøe Holding A/S Haldor Topsøes Allé 1 DK-2800 Kgs. Lyngby Denmark +45 4527 2000 (N

December 15, 2020 EX-99.8

Joint Filing Agreement, dated as of December 15, 2020, among Redmile Group, LLC, Jeremy C. Green and Redmile Capital Offshore Master Fund, Ltd.

EX-99.8 2 tm2038546d1ex99-8.htm EXHIBIT 99.8 Exhibit 99.8 Joint Filing Agreement In accordance with Rule 13d-1(k)(1) under the Securities Exchange Act of 1934, as amended (the “Exchange Act”), the undersigned hereby agree to the joint filing on behalf of each of them of a Statement on Schedule 13D (including any and all amendments thereto, the “Schedule 13D”) relating to the common stock, $0.01 pa

December 15, 2020 SC 13D/A

UNITED STATES SECURITIES & EXCHANGE COMMISSION Washington, D.C. 20549

UNITED STATES SECURITIES & EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13D Under the Securities Exchange Act of 1934 (Amendment No. 2)* IGM Biosciences, Inc. (Name of Issuer) Common Stock, $0.01 par value per share (Title of Class of Securities) 449585108 (CUSIP Number) Redmile Group, LLC Jeremy C. Green One Letterman Drive, Bldg D, Ste D3-300 San Francisco, CA 94129 Attention: Legal Depar

December 11, 2020 SC 13D/A

IGMS / IGM Biosciences, Inc. / BAKER BROS. ADVISORS LP - SCHEDULE 13D/A Activist Investment

SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 SCHEDULE 13D (Rule 13d-102) INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT TO RULE 13d-l(a) AND AMENDMENTS THERETO FILED PURSUANT TO RULE 13d-2(a) (Amendment No.

December 9, 2020 EX-4.1

Form of Pre-Funded Warrant

EX-4.1 Exhibit 4.1 FORM OF PRE-FUNDED WARRANT TO PURCHASE COMMON STOCK Number of Shares: [ ] (subject to adjustment) Warrant No. Original Issue Date: [ ], 2020 IGM Biosciences, Inc., a Delaware corporation (the “Company”), hereby certifies that, for good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, [ ] or its registered assigns (the “Holder”), is entitl

December 9, 2020 8-K

Entry into a Material Definitive Agreement, Financial Statements and Exhibits

8-K 1 d62530d8k.htm 8-K UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) December 8, 2020 IGM Biosciences, Inc. (Exact name of registrant as specified in its charter) Delaware 001-39045 77-0349194 (State or other jurisdiction of inco

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