# EDGAR Filing Document

**Accession Number:** 0001496323
**File Stem:** 0001140361-25-025957
**Filing Date:** 2025-7
**Character Count:** 435059
**Document Hash:** 1a826cb8ddf749cd6f94189e2ef688c4
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001140361-25-025957.hdr.sgml**: 20250722

**ACCESSION NUMBER**: 0001140361-25-025957

**CONFORMED SUBMISSION TYPE**: SC TO-T

**PUBLIC DOCUMENT COUNT**: 18

**FILED AS OF DATE**: 20250716

**DATE AS OF CHANGE**: 20250716

**GROUP MEMBERS**: CONCENTRA MERGER SUB V, INC.

**GROUP MEMBERS**: TANG CAPITAL MANAGEMENT, LLC

**GROUP MEMBERS**: TANG CAPITAL PARTNERS, LP

**SUBJECT COMPANY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** IGM Biosciences, Inc.
- **CENTRAL INDEX KEY:** 0001496323
- **STANDARD INDUSTRIAL CLASSIFICATION:** PHARMACEUTICAL PREPARATIONS [2834]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 770349194
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** SC TO-T
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 005-91132
- **FILM NUMBER:** 251126576

**BUSINESS ADDRESS:**
- **STREET 1:** 325 E MIDDLEFIELD ROAD
- **CITY:** MOUNTAIN VIEW
- **STATE:** CA
- **ZIP:** 94043
- **BUSINESS PHONE:** 650-965-7873

**MAIL ADDRESS:**
- **STREET 1:** 325 E MIDDLEFIELD ROAD
- **CITY:** MOUNTAIN VIEW
- **STATE:** CA
- **ZIP:** 94043

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** Palingen, Inc.
- **DATE OF NAME CHANGE:** 20100712
**FILED BY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Concentra Biosciences, LLC
- **CENTRAL INDEX KEY:** 0001970065

**ORGANIZATION NAME:**
- **EIN:** 922825109
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** SC TO-T

**BUSINESS ADDRESS:**
- **STREET 1:** 4747 EXECUTIVE DRIVE, SUITE 210
- **CITY:** SAN DIEGO
- **STATE:** CA
- **ZIP:** 92121
- **BUSINESS PHONE:** 8582003830

**MAIL ADDRESS:**
- **STREET 1:** 4747 EXECUTIVE DRIVE, SUITE 210
- **CITY:** SAN DIEGO
- **STATE:** CA
- **ZIP:** 92121

### UNITED STATES <br>

### SECURITIES AND EXCHANGE COMMISSION <br>

#### Washington, D.C. 20549

### SCHEDULE TO

#### TENDER OFFER STATEMENT UNDER SECTION 14(d)(1) OR 13(e)(1) <br>

#### OF THE SECURITIES EXCHANGE ACT OF 1934

### IGM BIOSCIENCES, INC. <br>

#### (Name of Subject Company (Issuer))

### CONCENTRA BIOSCIENCES, LLC <br>

#### (Name of Filing Persons (Co-Offeror 1))

### CONCENTRA MERGER SUB V, INC. <br>

#### (Name of Filing Persons (Co-Offeror 2))

### TANG CAPITAL PARTNERS, LP <br>

#### (Name of Filing Persons (Co-Offeror 3))

### TANG CAPITAL MANAGEMENT, LLC <br>

#### (Name of Filing Persons (Co-Offeror 4))

#### Common Stock, Par Value $0.01 Per Share <br>

#### (Title of Class of Securities) <br>

#### 449585108 <br>

#### (CUSIP Number of Class of Securities)

#### Kevin Tang <br>

#### Concentra Biosciences, LLC <br>

#### 4747 Executive Drive, Suite 210 <br>

#### San Diego, California 92121 <br>

#### Tel. (858) 281-5372 <br>

#### (Name, Address and Telephone Number of Person Authorized to Receive Notices <br>

#### and Communications on Behalf of Filing Persons)

#### Copies to: <br>

#### Ryan A. Murr <br>

#### Gibson, Dunn & Crutcher LLP <br>

#### One Embarcadero Center, Suite 2600 <br>

#### San Francisco, CA 94111
Check the box if the filing relates solely to preliminary communications made before the commencement of a tender offer. ☐

Check the appropriate boxes below to designate any transactions to which the statement relates:

☒<br> third-party tender offer subject to Rule 14d-1.

☐<br> issuer tender offer subject to Rule 13e-4.

☐<br> going-private transaction subject to Rule 13e-3.

☐<br> amendment to Schedule 13D under Rule 13d-2.

Check the following box if the filing is a final amendment reporting the results of the tender offer. ☐

If applicable, check the appropriate box(es) below to designate the appropriate rule provision(s) relied upon:

☐<br> Rule 13e-4(i) (Cross-Border Issuer Tender Offer)

☐<br> Rule 13d-1(d) (Cross-Border Third-Party Tender Offer)

------

This Tender Offer Statement on Schedule TO (this "<u>Schedule TO</u>") relates to the offer (the "<u>Offer</u>") by Concentra Biosciences, LLC, a Delaware limited liability company ("<u>Parent</u>" or "<u>Purchaser</u>"), to purchase all of the issued and outstanding shares of voting and non-voting common stock, par value $0.01 per share ("<u>Shares</u>"), of IGM Biosciences, Inc., a Delaware corporation ("<u>IGM</u>"), for: (i) $1.247 per Share in cash (the "<u>Cash</u> <u>Amount</u>"); plus (ii) one non-transferable contractual contingent value right for each Share (each, a "<u>CVR,</u>" and each CVR together with the Cash Amount, the "<u>Offer Price</u>"), all upon the terms and subject to the conditions described in the Offer to Purchase (together with any amendments or supplements hereto, the "<u>Offer to</u> <u>Purchase</u>") and in the related Letter of Transmittal (together with any amendments or supplements thereto, the "<u>Letter of Transmittal</u>"), copies of which are attached hereto as Exhibits (a)(1)(A) and (a)(1)(B), respectively. The Offer is being made pursuant to the Agreement and Plan of Merger, dated as of July 1, 2025 (together with any amendments or supplements thereto, the "<u>Merger Agreement</u>"), among IGM, Parent and Concentra Merger Sub V, Inc., a Delaware corporation ("<u>Merger Sub</u>") and a wholly owned subsidiary of Parent, a copy of which is filed as Exhibit (d)(1) hereto and incorporated herein by reference with respect to Items 4 through 11 of this Schedule TO. Capitalized terms used but not otherwise defined herein have the meanings ascribed thereto in the Merger Agreement.

All of the information set forth in the Offer to Purchase is incorporated by reference herein in response to Items 1 through 9 and Item 11 of this Schedule TO and is supplemented by the information specifically provided in this Schedule TO.

---

| | |
|:---|:---|
| **ITEM 1.**<br>| **SUMMARY TERM SHEET.**  |

---

The information set forth in the section of the Offer to Purchase titled "Summary Term Sheet" is incorporated herein by reference.

---

| | |
|:---|:---|
| **ITEM 2.**<br>| **SUBJECT COMPANY INFORMATION.**  |

---

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(a) The subject company and the issuer of the securities subject to the Offer is IGM. IGM terminated its lease agreements for office space and, accordingly, IGM does not maintain headquarters. For purposes of compliance with applicable requirements of the Securities Act of 1933, as amended, and Securities Exchange Act of 1934, as amended, any stockholder communication required to be sent to IGM's principal executive offices may be sent to IGM Biosciences, Inc., 3 East Third Avenue, Suite 200, San Mateo, California 94401. IGM's telephone number is (650) 965-7873.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(b) This Schedule TO relates to the Shares. According to IGM as of the close of business on June 27, 2025, there were: (i) 60,189,151 Shares issued and outstanding (34,802,168 shares of voting common stock and 25,386,983 shares of non-voting common stock); (ii) no Shares held by IGM in its treasury; (iii) 4,308,913 Shares subject to outstanding Company Stock Options with a weighted-average exercise price of approximately $16.27 per share, 96,328 of which were In-the-Money Options with a weighted-average exercise price of approximately $1.00 per share; (iv) 1,030,014 Shares subject to outstanding Company Restricted Stock Units; and (v) 1,334,332 Shares subject to Company Pre-Funded Warrants, with an exercise price of $0.01 per Share.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(c) The information concerning the principal market on which the Shares are traded, and certain high and low sales prices for the Shares in the principal market in which the Shares are traded set forth in "Special Factors—Section 4. Price Range of Shares; Dividends" of the Offer to Purchase, are incorporated herein by reference.

---

| | |
|:---|:---|
| **ITEM 3.**<br>| **IDENTITY AND BACKGROUND OF FILING PERSON.**  |

---

(a)–(c) The filing companies of this Schedule TO, Parent, Merger Sub, TCP (as defined below) and TCM (as defined below). Each of Parent's, Merger Sub's, TCP's and TCM's principal executive office is located at 4747 Executive Drive, Suite 210, San Diego, California 92121. Each of Parent's and Merger Sub's telephone number is (858) 281-5372. Each of TCP's and TCM's telephone number is (858) 200-3830.

Parent was formed under the laws of the State of Delaware on March 8, 2023 and its principal business is currently to consummate the Offer and effect the Merger pursuant to the Merger Agreement, and to perform its obligations under the contingent value rights agreement, which is in substantially the form attached as Exhibit D to the Merger Agreement (the "<u>CVR Agreement</u>"), following the Merger when IGM is a wholly owned subsidiary of Parent and the surviving entity from the Merger. The executive officers of Parent are: (i) Mr. Tang,

------

Chief Executive Officer; (ii) Michael Hearne, Chief Financial Officer; (iii) Ryan Cole, Chief Operating Officer; (iv) Stew Kroll, Chief Development Officer; and (v) Thomas Wei, Chief Business Officer. Each executive officer of Parent is a United States citizen and has a business address located at 4747 Executive Drive, Suite 210, San Diego, California 92121.

Merger Sub was incorporated under the laws of the State of Delaware on May 19, 2025 for the purpose of consummating and effecting the Merger pursuant to the Merger Agreement. Kevin Tang is the sole director of Merger Sub, and the executive officers of Merger Sub are: (i) Mr. Tang, Chief Executive Officer; (ii) Michael Hearne, Chief Financial Officer; (iii) Ryan Cole, Chief Operating Officer; (iv) Stew Kroll, Chief Development Officer; and (v) Thomas Wei, Chief Business Officer. Each executive officer of Merger Sub is a United States citizen and has a business address located at 4747 Executive Drive, Suite 210, San Diego, California 92121.

Tang Capital Partners, LP ("<u>TCP</u>") was formed under the laws of the State of Delaware on August 16, 2002, and is the sole member of Parent. Its principal business is a life sciences-focused investment company.

Tang Capital Management, LLC ("<u>TCM</u>") was formed under the laws of the State of Delaware on December 19, 2012. TCM is the sole manager of Parent and general partner of TCP. Its principal business is a life sciences-focused investment management company. Mr. Tang is the sole manager of TCM. The executive officers of TCM are: (i) Mr. Tang, President; (ii) Michael Hearne, Chief Financial Officer; and (iii) Ryan Cole, Chief Operating Officer. Each executive officer of TCM is a United States citizen and has a business address located at 4747 Executive Drive, Suite 210, San Diego, California 92121.

The information set forth in "The Tender Offer—Section 6. Certain Information Concerning Parent and Merger Sub" and Schedule A of the Offer to Purchase is incorporated herein by reference.

---

| | |
|:---|:---|
| **ITEM 4.**<br>| **TERMS OF THE TRANSACTION.**  |

---

(a)(1)(i)-(viii), (x), (xii), (a)(2)(i)-(v), (vii) The information set forth in the Offer to Purchase is incorporated herein by reference.

(a)(1)(ix), (xi), (a)(2)(vi) Not applicable.

---

| | |
|:---|:---|
| **ITEM 5.**<br>| **PAST CONTACTS, TRANSACTIONS, NEGOTIATIONS AND AGREEMENTS.**  |

---

(a), (b) The information set forth in "Special Factors—Section 1. Background of the Offer; Contacts with IGM," "Special Factors—Section 2. Purpose of the Offer and Plans for IGM" "The Tender Offer—Section 5. Certain Information Concerning IGM" "The Tender Offer—Section 6. Certain Information Concerning Parent and Merger Sub" and Schedule A of the Offer to Purchase is incorporated herein by reference.

---

| | |
|:---|:---|
| **ITEM 6.**<br>| **PURPOSES OF THE TRANSACTION AND PLANS OR PROPOSALS.**  |

---

(a), (c)(1)–(7) The information set forth in the sections of the Offer to Purchase titled "Summary Term Sheet" and "Introduction" and in "Special Factors—Section 2. Purpose of the Offer and Plans for IGM" "Special Factors—Section 5. Price Range of Shares; Dividends," "Special Factors—Section 5. Possible Effects of the Offer on the Market for the Shares; Nasdaq Listing; Exchange Act Registration and Margin Regulations," "The Tender Offer—Section 1. Terms of the Offer" and "The Tender Offer—Section 7. Summary of the Merger Agreement and Certain Other Agreements" of the Offer to Purchase is incorporated herein by reference.

---

| | |
|:---|:---|
| **ITEM 7.**<br>| **SOURCE AND AMOUNT OF FUNDS OR OTHER CONSIDERATION.**  |

---

(a), (d) The information set forth in the section of the Offer to Purchase titled "Summary Term Sheet" and in "The Tender Offer—Section 8. Source and Amount of Funds" of the Offer to Purchase is incorporated herein by reference.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(b) The Offer is not subject to a financing condition.

---

| | |
|:---|:---|
| **ITEM 8.**<br>| **INTEREST IN SECURITIES OF THE SUBJECT COMPANY.**  |

---

The information set forth in "Special Factors—Section 2. Purpose of the Offer and Plans for IGM" "The Tender Offer—Section 6. Certain Information Concerning Parent and Merger Sub" and Schedule A—"Information Concerning Members of the Boards of Directors and the Executive Officers of Parent, Merger Sub and the Guarantor" of the Offer to Purchase and Item 3—"Identity and Background of the Filing Person" hereof is incorporated herein by reference.

------

---

| | |
|:---|:---|
| **ITEM 9.**<br>| **PERSONS/ASSETS RETAINED, EMPLOYED, COMPENSATED OR USED.**  |

---

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(a) The information set forth in the section of the Offer to Purchase titled "Introduction" and in "Special Factors—Section 1. Background of the Offer; Contacts with IGM" "The Tender Offer—Section 3. Procedures for Tendering Shares" and "The Tender Offer—Section 12. Fees and Expenses" of the Offer to Purchase is incorporated herein by reference.

---

| | |
|:---|:---|
| **ITEM 10.**<br>| **FINANCIAL STATEMENTS.**  |

---

Not applicable. The consideration offered to security holders: (i) consists solely of cash; (ii) any payments of CVR Proceeds will be self-funded (as more fully described in the Offer to Purchase); (iii) the Offer is not subject to any financing condition; and (iv) the offer is for all outstanding securities of the subject class.

---

| | |
|:---|:---|
| **ITEM 11.**<br>| **ADDITIONAL INFORMATION.**  |

---

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(a) The information set forth in "Special Factors—Section 1. Background of the Offer; Contacts with IGM" "Special Factors—Section 2. Purpose of the Offer and Plans for IGM" "Special Factors—Section 5. Possible Effects of the Offer on the Market for the Shares; Nasdaq Listing; Exchange Act Registration and Margin Regulations," "The Tender Offer—Section 6. Certain Information Concerning Parent and Merger Sub," "The Tender Offer—Section 7. Summary of the Merger Agreement and Certain Other Agreements" and "The Tender Offer—Section 11. Certain Legal Matters; Regulatory Approvals" of the Offer to Purchase is incorporated herein by reference.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(c) The information set forth in the Offer to Purchase is incorporated herein by reference.

---

| | |
|:---|:---|
| **ITEM 12.**<br>| **EXHIBITS.**  |

---

---

| | |
|:---|:---|
| **Index No.** |  |
| [(a)(1)(A)\*](ny20051934x1_exa1a.htm) | Offer to Purchase, dated July 16, 2025  |
| [(a)(1)(B)\*](ny20051934x1_exa1b.htm) | Form of Letter of Transmittal  |
| [(a)(1)(C)\*](ny20051934x1_exa1c.htm) | Form of Letter to Brokers, Dealers, Commercial Banks, Trust Companies and Other Nominees  |
| [(a)(1)(D)\*](ny20051934x1_exa1d.htm) | Form of Letter to Clients for Use by Brokers, Dealers, Commercial Banks, Trust Companies and Other Nominees  |
| [(a)(5)(A)](https://www.sec.gov/Archives/edgar/data/1496323/000119312525153576/d82329dex991.htm) | Press Release of IGM issued on July 1, 2025 (incorporated by reference to Exhibit 99.1 to IGM's Current Report on Form 8-K (File No. 001-39045) filed with the SEC on July 1, 2025)  |
| (b) | Not applicable  |
| [(d)(1)](https://www.sec.gov/Archives/edgar/data/1496323/000119312525153576/d82329dex21.htm) | Agreement and Plan of Merger, dated July 1, 2025, by and among Concentra Biosciences, LLC, Concentra Merger Sub V, Inc. and IGM Biosciences, Inc. (incorporated by reference to Exhibit 2.1 to IGM's Current Report on Form 8-K (File No. 001-39045) filed with the SEC on July 1, 2025)  |
| [(d)(2)\*](ny20051934x1_exd2.htm) | Confidentiality Agreement dated May 27, 2025 between IGM and Parent  |
| [(d)(3)\*](ny20051934x1_exd3.htm) | Limited Guaranty, dated July 1, 2025  |
| [(d)(4)](https://www.sec.gov/Archives/edgar/data/1496323/000119312525153576/d82329dex101.htm) | Form of Contingent Value Rights Agreement (incorporated by reference to Exhibit 10.1 to IGM's Current Report on Form 8-K (File No. 001-39045) filed with the SEC on July 1, 2025)  |
| (g) | Not applicable  |
| (h) | Not applicable  |
| [107\*](ny20051934x1_ex107.htm) | Filing Fee Table |

---

\*<br> Filed herewith.

---

| | |
|:---|:---|
| **ITEM 13.**<br>| **INFORMATION REQUIRED BY SCHEDULE 13E-3.**  |

---

Not applicable.

------

#### SIGNATURE
After due inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Dated: July 16, 2025

---

| | | |
|:---|:---|:---|
| **CONCENTRA BIOSCIENCES, LLC**  | **CONCENTRA BIOSCIENCES, LLC**  | **CONCENTRA BIOSCIENCES, LLC**  |
| By: | /s/ Kevin Tang | /s/ Kevin Tang |
|  | Name: | Kevin Tang  |
|  | Title: | *Chief Executive Officer*  |
| **CONCENTRA MERGER SUB V, INC.**  | **CONCENTRA MERGER SUB V, INC.**  | **CONCENTRA MERGER SUB V, INC.**  |
| By: | /s/ Kevin Tang | /s/ Kevin Tang |
|  | Name: | Kevin Tang  |
|  | Title: | *Chief Executive Officer*  |
| **TANG CAPITAL PARTNERS, LP**  | **TANG CAPITAL PARTNERS, LP**  | **TANG CAPITAL PARTNERS, LP**  |
| By: | /s/ Kevin Tang | /s/ Kevin Tang |
|  | Name: | Kevin Tang  |
|  | Title: | *Manager of Tang Capital Management, LLC,*<br>*General Partner of Tang Capital Partners, LP*  |
| **TANG CAPITAL MANAGEMENT, LLC**  | **TANG CAPITAL MANAGEMENT, LLC**  | **TANG CAPITAL MANAGEMENT, LLC**  |
| By: | /s/ Kevin Tang | /s/ Kevin Tang |
|  | Name: | Kevin Tang  |
|  | Title: | *Manager* |

---

## Ex-99.(A)(1)(A)

#### **TABLE OF CONTENTS**

#### Exhibit (a)(1)(A)

#### Offer to Purchase <br>

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>

#### All Outstanding Shares of Common Stock <br>

#### of <br>

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>

### IGM BIOSCIENCES, INC. <br>

### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>

#### at <br>
**A Cash Amount of $1.247 per Share, Plus One Non-Transferable Contractual Contingent Value Right for Each Share ("<u>CVR</u>"), Which Represents the Right to Receive One or More Potential Cash Payments, Contingent upon: (i) the Receipt of Proceeds from Any CVR Product or Company Patent Disposition that Occurs Within One (1) Year Following the Merger Closing Date and Such Proceeds Are Received by or Otherwise Due to Parent or Any of Its Affiliates by the First (1st) Anniversary Following the Merger Closing Date; and (ii) Closing Net Cash in Excess of $82,000,000, As Determined Five (5) Business Days Prior to the Merger Closing Date, as Described in the CVR Agreement.** 

<br> #### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>

#### by <br>

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>

#### CONCENTRA BIOSCIENCES, LLC <br>

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>

#### and <br>

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>

#### CONCENTRA MERGER SUB V, INC. <br>

#### a wholly owned subsidiary of Purchaser <br>

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>

#### and <br>

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>

#### TANG CAPITAL PARTNERS, LP <br>

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>

#### and <br>

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>

#### TANG CAPITAL MANAGEMENT, LLC <br>

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>

#### THE OFFER AND WITHDRAWAL RIGHTS WILL EXPIRE ONE MINUTE AFTER <br>

#### 11:59 P.M. EASTERN TIME ON AUGUST 13, 2025 (THE " EXPIRATION DATE "), <br>

#### UNLESS THE OFFER IS EXTENDED OR EARLIER TERMINATED.
Concentra Biosciences, LLC, a Delaware limited liability company ("<u>Parent</u>" or "<u>Purchaser</u>"), is offering to purchase (the "<u>Offer</u>") all outstanding shares of voting and non-voting common stock, par value $0.01 per share ("<u>Shares</u>"), of IGM Biosciences, Inc., a Delaware corporation ("<u>IGM</u>"), for: (i) $1.247 per Share in cash (the "<u>Cash</u> <u>Amount</u>"); and (ii) one non-transferable contractual contingent value right for each Share (each, a "<u>CVR,</u>" and each CVR together with the Cash Amount, the "<u>Offer Price</u>"), all upon the terms and subject to the conditions described in this Offer to Purchase (together with any amendments or supplements hereto, this "<u>Offer to Purchase</u>") and in the related Letter of Transmittal (together with any amendments or supplements thereto, the "<u>Letter of Transmittal</u>"). Subject to the terms of the Merger Agreement (as defined below) and the CVR Agreement (as defined below), the Offer Price will be paid net of any applicable tax withholding and without interest.

The Offer is being made pursuant to the Agreement and Plan of Merger, dated as of July 1, 2025 (together with any amendments or supplements thereto, the "<u>Merger Agreement</u>"), among IGM, Parent and Concentra Merger Sub V, Inc., a Delaware corporation ("<u>Merger Sub</u>") and a wholly owned subsidiary of Parent, pursuant to which, after the completion of the Offer and the satisfaction or waiver of certain conditions, Merger Sub will be merged with and into IGM, without a meeting or any further action of the IGM stockholders in accordance with Section 251(h) of the General Corporation Law of the State of Delaware (the "<u>DGCL</u>"), and IGM will be the surviving corporation and a wholly owned subsidiary of Parent (such corporation, the "<u>Surviving</u> <u>Corporation</u>" and such merger, the "<u>Merger</u>"). Accordingly, Merger Sub is considered a co-offeror in the Offer. The time at which the Merger becomes effective is referred to as the "<u>Effective Time</u>" and the date upon which the Merger becomes effective is the "<u>Closing Date</u>." Upon the terms and subject to the satisfaction or waiver of the conditions of the Offer and the Merger Agreement, including the Minimum Tender Condition (as defined below), Purchaser will accept for payment (the date and time of such acceptance, the "<u>Offer Closing Time</u>") and thereafter pay for all Shares validly tendered and not properly withdrawn pursuant to the Offer promptly after the Expiration Date.

------

#### **TABLE OF CONTENTS**
Concurrently with the execution of the Merger Agreement, and as a condition and inducement to IGM's willingness to enter into the Merger Agreement, Tang Capital Partners, LP, a Delaware limited partnership ("<u>TCP</u>" or "<u>Guarantor</u>") and sole member of Parent, delivered to IGM a duly executed limited guaranty (the "<u>Limited Guaranty</u>"), dated as of the date of the Merger Agreement, in favor of IGM, in respect of certain obligations of Parent and Merger Sub under the Merger Agreement and the CVR Agreement. Certain obligations under the Limited Guaranty are subject to a cap of $78,000,000, which includes certain Enforcement Costs under the Merger Agreement and an amount equivalent to the CVR Proceeds (as defined below) under the CVR Agreement. Tang Capital Management, LLC, a Delaware limited liability company ("<u>TCM</u>"), is the sole manager of Parent and the general partner of TCP. Accordingly, TCP and TCM are considered co-offerors in the Offer. As co-offerors, TCP and TCM accept joint responsibility for the accuracy of the disclosures made in this Offer to Purchase.

Pursuant to the terms of the Merger Agreement, at the Effective Time, by virtue of the Merger and without any action on the part of the holders of Shares, each outstanding Share, other than Shares held in the treasury by IGM, held by any stockholders, or owned by any beneficial owners, of IGM who are entitled to and who properly exercise appraisal rights under Delaware law or owned by Parent, Merger Sub or any other subsidiary of Parent at the commencement of the Offer and is owned by Parent, Merger Sub or any other subsidiary of Parent immediately prior to the Effective Time, will be converted into the right to receive the Offer Price, without interest and subject to any applicable tax withholding. As of immediately prior to the Effective Time, the vesting for each option to purchase Shares from IGM ("<u>Company Stock Options</u>," and each a "<u>Company Stock</u> <u>Option</u>") and, as of immediately prior to the Offer Closing Time, the vesting for each restricted stock units granted by IGM ("<u>Company Restricted Stock Units</u>," and each a "<u>Company Restricted Stock Unit</u>"), shall be accelerated and: (i) (A) each Company Stock Option that has an exercise price per share that is less than the Cash Amount (each, an "<u>In-the-Money Option</u>") that is then outstanding will be cancelled and, in exchange therefor, the holder of such cancelled In-the-Money Option will be entitled to receive in consideration of the cancellation of such In-the-Money Option (1) an amount in cash without interest, less any applicable tax withholding, equal to the product obtained by multiplying (x) the excess of the Cash Amount over the exercise price per share of Shares underlying such In-the-Money Option by (y) the number of Shares underlying such In-the-Money Option as of immediately prior to the Effective Time, and (2) one CVR for each Share underlying such In-the-Money Option, and (B) each Company Stock Option that has an exercise price per share that is equal to or greater than the Cash Amount that is then outstanding will be cancelled for no consideration; and (ii) each Company Restricted Stock Unit that is then outstanding will be cancelled and, in exchange therefor, the holder of such cancelled Company Restricted Stock Unit will be entitled to receive in consideration of the cancellation of such Company Restricted Stock Unit (A) an amount in cash without interest, less any applicable tax withholding, equal to the Cash Amount, and (B) one CVR.

Prior to the Effective Time, IGM shall satisfy all of its notification requirements under the terms of each outstanding and unexercised Company Pre-Funded Warrant, and, at the Effective Time, each Company Pre-Funded Warrant shall be canceled and holders of such warrants will be entitled to receive: (1) an amount in cash without interest, less any applicable tax withholding, equal to the product obtained by multiplying (x) the excess of the Cash Amount over the exercise price per share of such Company Pre-Funded Warrant by (y) the number of Shares underlying such Company Pre-Funded Warrant as of immediately prior to the Effective Time; and (2) one CVR for each Share underlying such Company Pre-Funded Warrant.

**As noted in the Summary Term Sheet, there is a risk that you may receive no payments under the CVRs. Therefore, in making a decision to tender your Shares, you should understand that if the CVR does not generate any payments, the only consideration that you would receive is the Cash Amount of $1.247 per Share that is being offered pursuant to the Offer. You should base your tender decision on the Cash Amount as it may be the only consideration you receive in the Offer. On July 15, 2025, the last full trading day prior to the date of this Offer to Purchase, the closing price of IGM's common stock as reported on Nasdaq was $1.35 per Share.** 

**On July 1, 2025, the IGM board of directors (the "<u>IGM Board</u>") at a duly called and held meeting, duly and by unanimous vote: (i) determined that the terms of the Merger Agreement, the Offer and the other transactions contemplated by the Merger Agreement and the CVR Agreement (collectively, the "<u>Transactions</u>") are advisable, fair to, and in the best interests of, IGM and IGM's stockholders; (ii) approved and declared advisable the Merger Agreement and the Transactions; (iii) authorized and** 

------

**approved the execution, delivery and performance by IGM of the Merger Agreement and the consummation by IGM of the Transactions; (iv) resolved to recommend that IGM's stockholders accept the Offer and tender their shares of IGM Common Stock in the Offer; and (v) resolved that the Merger Agreement and the Merger shall be governed by and effected under Section 251(h) of the DGCL and the Merger will be consummated as soon as practicable following the Offer Closing Time.** 

**The Offer is subject to various conditions. See "<u>The Tender Offer—Section 9. Conditions of the</u> <u>Offer</u>." A summary of the principal terms of the Offer appears on pages [45](#tCOT) through [46](#tDAD) of this Offer to Purchase. You should read this entire document carefully before deciding whether to tender your Shares.** 

**Neither the U.S. Securities and Exchange Commission nor any state securities commission has approved or disapproved of this transaction, passed upon the merits or fairness of such transaction or passed upon the adequacy or accuracy of the information contained in this document. Any representation to the contrary is a criminal offense.** 

Unless otherwise indicated in this Offer to Purchase or the context otherwise requires, all references in this Offer to Purchase to "we," "our," or "us" refer to Parent, Merger Sub, Guarantor or TCP as the context requires.

July 16, 2025

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#### IMPORTANT
If you desire to tender all or any portion of your Shares to us pursuant to the Offer, you should either: (i) if you hold your Shares directly as the registered owner, complete and sign the Letter of Transmittal for the Offer, which is enclosed with this Offer to Purchase, in accordance with the instructions contained in the Letter of Transmittal, mail or deliver the Letter of Transmittal and any other required documents to Broadridge Corporate Issuer Solutions, LLC (the "<u>Depositary and Paying Agent</u>"), and deliver the certificates (if any) for your Shares to the Depositary and Paying Agent along with the Letter of Transmittal of this Offer to Purchase prior to the expiration of the Offer; or (ii) if you hold your Shares in "street name," request that your broker, dealer, commercial bank, trust company or other nominee effect the transaction for you. **If you hold Shares registered in the name of a broker, dealer, commercial bank, trust company or other nominee you must contact that institution in order to tender your Shares to us pursuant to the Offer.**

#### \* \* \*
Questions and requests for assistance may be directed to MacKenzie Partners, Inc. (the "<u>Information</u> <u>Agent</u>") at its address and telephone number set forth on the back cover of this Offer to Purchase. Requests for additional copies of this Offer to Purchase, the Letter of Transmittal and other tender offer materials may be directed to the Information Agent. You may also contact your broker, dealer, commercial bank, trust company or other nominee for assistance.

This Offer to Purchase and the Letter of Transmittal contain important information, and you should read both carefully and in their entirety before making any decision with respect to the Offer.

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#### **TABLE OF CONTENTS**

---

| | | |
|:---|:---|:---|
|  |  | **Page**  |
| **[SUMMARY TERM SHEET](#tSUM)** | **[SUMMARY TERM SHEET](#tSUM)** | &nbsp;&nbsp;[1](#tSUM) |
| **[INTRODUCTION](#tINR)** | **[INTRODUCTION](#tINR)** | [12](#tINR) |
| **[SPECIAL FACTORS](#tSF)** | **[SPECIAL FACTORS](#tSF)** | [14](#tSF) |
| [1.](#tBOT) | [BACKGROUND OF THE OFFER; CONTACTS WITH IGM.](#tBOT) | [14](#tBOT) |
| [2.](#tPOT) | [PURPOSE OF THE OFFER AND PLANS FOR IGM.](#tPOT) | [16](#tPOT) |
| [3.](#tROA) | [REPORTS, OPINIONS, APPRAISALS AND NEGOTIATIONS.](#tROA) | [17](#tROA) |
| [4.](#tPRO) | [PRICE RANGE OF SHARES; DIVIDENDS.](#tPRO) | [17](#tPRO) |
| [5.](#tPEO) | &nbsp;&nbsp;[POSSIBLE EFFECTS OF THE OFFER ON THE MARKET FOR THE SHARES; NASDAQ LISTING; EXCHANGE ACT REGISTRATION AND MARGIN REGULATIONS.](#tPEO) | [18](#tPEO) |
| [6.](#tUS) | [MATERIAL U.S. FEDERAL INCOME TAX CONSEQUENCES OF THE OFFER AND THE MERGER.](#tUS) | [19](#tUS) |
| &nbsp;&nbsp;**[THE TENDER OFFER](#tTTR)** | &nbsp;&nbsp;**[THE TENDER OFFER](#tTTR)** | [25](#tTTR) |
| [1.](#tTOT) | [TERMS OF THE OFFER.](#tTOT) | [25](#tTOT) |
| [2.](#tAFP) | [ACCEPTANCE FOR PAYMENT AND PAYMENT FOR SHARES.](#tAFP) | [27](#tAFP) |
| [3.](#tPFT) | [PROCEDURES FOR TENDERING SHARES.](#tPFT) | [27](#tPFT) |
| [4.](#tWR) | [WITHDRAWAL RIGHTS.](#tWR) | [29](#tWR) |
| [5.](#tCIC) | [CERTAIN INFORMATION CONCERNING IGM.](#tCIC) | [30](#tCIC) |
| [6.](#tCICP) | [CERTAIN INFORMATION CONCERNING PARENT AND MERGER SUB.](#tCICP) | [31](#tCICP) |
| [7.](#tSOTM) | [SUMMARY OF THE MERGER AGREEMENT AND CERTAIN OTHER AGREEMENTS.](#tSOTM) | [32](#tSOTM) |
| [8.](#tSAA) | [SOURCE AND AMOUNT OF FUNDS.](#tSAA) | [44](#tSAA) |
| [9.](#tCOT) | [CONDITIONS OF THE OFFER.](#tCOT) | [45](#tCOT) |
| [10.](#tDAD) | &nbsp;&nbsp;[DIVIDENDS AND DISTRIBUTIONS.](#tDAD) | [46](#tDAD) |
| [11.](#tCLM) | &nbsp;&nbsp;[CERTAIN LEGAL MATTERS; REGULATORY APPROVALS.](#tCLM) | [46](#tCLM) |
| [12.](#tFAE) | [FEES AND EXPENSES.](#tFAE) | [50](#tFAE) |
| [13.](#tMIS) | [MISCELLANEOUS.](#tMIS) | [50](#tMIS) |

---

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#### SUMMARY TERM SHEET
Concentra Biosciences, LLC, a Delaware limited liability company ("<u>Parent</u>" or "<u>Purchaser</u>"), is offering to purchase (the "<u>Offer</u>") all outstanding shares of voting and non-voting common stock, par value $0.01 per share ("<u>Shares</u>"), of IGM Biosciences, Inc., a Delaware corporation ("<u>IGM</u>"), for: (i) $1.247 per Share in cash (the "<u>Cash</u> <u>Amount</u>"); and (ii) one non-transferable contractual contingent value right for each Share (each, a "<u>CVR,</u>" and each CVR together with the Cash Amount, the "Offer Price"), all upon the terms and subject to the conditions described in this Offer to Purchase (together with any amendments or supplements hereto, this "<u>Offer to Purchase</u>") and in the related Letter of Transmittal (together with any amendments or supplements thereto, the "<u>Letter of Transmittal</u>"). Subject to the terms of the Merger Agreement (as defined below) and the CVR Agreement (as defined below), the Offer Price will be paid net of any applicable tax withholding and without interest.

The Offer is being made pursuant to the Agreement and Plan of Merger, dated as of July 1, 2025 (together with any amendments or supplements thereto, the "<u>Merger Agreement</u>"), among IGM, Parent and Concentra Merger Sub V, Inc., a Delaware corporation ("<u>Merger Sub</u>") and a wholly owned subsidiary of Parent, pursuant to which, after the completion of the Offer and the satisfaction or waiver of certain conditions, Merger Sub will be merged with and into IGM, without a meeting or any further action of IGM stockholders in accordance with Section 251(h) of the General Corporation Law of the State of Delaware (the "<u>DGCL</u>"), and IGM will be the surviving corporation and a wholly owned subsidiary of Parent (such corporation, the "<u>Surviving Corporation</u>," and such merger, the "<u>Merger</u>"). Accordingly, Merger Sub is considered a co-offeror in the Offer. The time at which the Merger becomes effective is referred to as the "<u>Effective Time</u>" and the date upon which the Merger becomes effective is the "<u>Closing Date</u>." Upon the terms and subject to the satisfaction or waiver of the conditions of the Offer and the Merger Agreement, including the Minimum Tender Condition (as defined below), Purchaser will accept for payment (the date and time of such acceptance, the "<u>Offer Closing Time</u>") and thereafter pay for all Shares validly tendered and not properly withdrawn pursuant to the Offer promptly after the Expiration Date.

Concurrently with the execution of the Merger Agreement, and as a condition and inducement to IGM's willingness to enter into the Merger Agreement, Tang Capital Partners, LP, a Delaware limited partnership ("<u>TCP</u>" or "<u>Guarantor</u>") and sole member of Parent, delivered to IGM a duly executed limited guaranty (the "<u>Limited Guaranty</u>"), dated as of the date of the Merger Agreement, in favor of IGM, in respect of certain obligations of Parent and Merger Sub under the Merger Agreement and the CVR Agreement. Certain obligations under the Limited Guaranty are subject to a cap of $78,000,000, which includes certain Enforcement Costs, under the Merger Agreement and an amount equivalent to the CVR Proceeds (as defined below) under the CVR Agreement. Tang Capital Management, LLC, a Delaware limited liability company ("<u>TCM</u>"), is the sole manager of Parent and the general partner of TCP. Accordingly, TCP and TCM are considered co-offerors in the Offer. As co-offerors, TCP and TCM accept joint responsibility for the accuracy of the disclosures made in this Offer to Purchase.

The following are some questions you, as a stockholder of IGM, may have, and answers to those questions. This Summary Term Sheet highlights selected information from this Offer to Purchase and may not contain all of the information that is important to you; this Summary Term Sheet is qualified in its entirety by the more detailed descriptions and explanations contained in the Merger Agreement, the CVR Agreement, the Limited Guaranty, this Offer to Purchase and the related Letter of Transmittal. To better understand the Offer and for a complete description of the legal terms of the Offer, you should read the Merger Agreement, the CVR Agreement, the Limited Guaranty, this Offer to Purchase and the related Letter of Transmittal carefully and in their entirety. Questions or requests for assistance may be directed to MacKenzie Partners, Inc. (the "<u>Information</u> <u>Agent</u>") at its address and telephone number, as set forth on the back cover of this Offer to Purchase. Unless otherwise indicated in this Offer to Purchase or the context otherwise requires, all references in this Offer to Purchase to "we," "our," or "us" refer to Parent, Merger Sub, Guarantor or TCP as the context requires.

#### WHO IS OFFERING TO BUY MY SECURITIES?
&nbsp;&nbsp;&nbsp;&nbsp;• Parent is offering to buy your securities. See " <u>The Tender Offer—Section 6. Certain Information</u> <u>Concerning Parent and Merger Sub</u>." Certain obligations of Parent and Merger Sub under the Merger Agreement have been guaranteed by Tang Capital Partners, LP, pursuant to the Limited Guaranty.

&nbsp;&nbsp;&nbsp;&nbsp;• Parent is Concentra Biosciences, LLC. See " <u>The Tender Offer—Section 6. Certain Information</u> <u>Concerning Parent and Merger Sub</u>."

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&nbsp;&nbsp;&nbsp;&nbsp;• Merger Sub is Concentra Merger Sub V, Inc. See " <u>The Tender Offer—Section 6. Certain Information</u> <u>Concerning Parent and Merger Sub</u>." Merger Sub has been organized in connection with the Merger and has not carried on any activities other than entering into the Merger Agreement and activities in connection with the Offer.

&nbsp;&nbsp;&nbsp;&nbsp;• Guarantor is Tang Capital Partners, LP. See " <u>The Tender Offer—Section 6. Certain Information</u> <u>Concerning Parent and Merger Sub</u>."

&nbsp;&nbsp;&nbsp;&nbsp;• The sole manager of Parent and the general partner of Guarantor is Tang Capital Management, LLC. See " <u>The Tender Offer—Section 6. Certain Information Concerning Parent and Merger Sub</u>."

#### WHAT ARE THE CLASSES AND AMOUNTS OF SECURITIES SOUGHT IN THE OFFER?
&nbsp;&nbsp;&nbsp;&nbsp;• Purchaser is seeking to purchase all of the outstanding Shares of IGM. See the Introduction and " <u>The Tender Offer—Section 1. Terms of the Offer</u>."

#### HOW MUCH IS PURCHASER OFFERING TO PAY AND WHAT IS THE FORM OF PAYMENT?
&nbsp;&nbsp;&nbsp;&nbsp;• Purchaser is offering to pay: (i) $1.247 per Share in cash (the " <u>Cash Amount</u> "); and (ii) one non-transferable CVR for each Share, which represents the right to receive certain contingent cash payments equal to a pro rata share of the following, each pursuant to the CVR Agreement and collectively, the " <u>CVR Proceeds</u> ":

(i) "<u>Disposition Proceeds</u>": 80% of the Net Proceeds (as defined in the CVR Agreement), if any, from any sale, transfer, license or other disposition or grant of rights (each, a "<u>Disposition</u>") by Parent or any of its affiliates, including IGM after the Merger, of all or any part of: (a) IGM's product candidates known as: (A) imvotamab, an IgM-based CD20 X CD3 bispecific antibody T cell engager; (B) IGM-2644, an IgM-based CD38 X CD3 bispecific T cell engager; (C) aplitabart (or IGM-8444), a Death Receptor 5 agonist; (D) IGM-7354, a targeted IL-15/IL-15R IgM antibody; (E) IGM-8447, an IgM-based Death Receptor 5 agonist; and (F) IGM-2537, an IgM-based CD123 X CD3 bispecific antibody T cell engager (the "<u>CVR Products</u>"); or (b) patents and patent applications owned or controlled by the Company immediately prior to the closing of the Merger and set forth on Schedule 1 of the CVR Agreement, together with all patents issuing thereon or claiming priority thereto (the "Company Patents"), that occurs within the period beginning on the Merger Closing Date (as defined in the Merger Agreement) and ending on the first (1<sup>st</sup>) anniversary following the Merger Closing Date, and such Gross Proceeds (as defined in the CVR Agreement) are received by or otherwise due to Parent or any of its Affiliates by the first (1<sup>st</sup>) anniversary following the Merger Closing Date; and 

(ii) "<u>Additional Closing Net Cash Proceeds</u>": 100% of the amount by which the Closing Net Cash as finally determined pursuant to the Merger Agreement exceeds $82,000,000, adjusted for any claims Parent reasonably determines to be valid five (5) business days prior to the Merger Closing Date that are not accounted for in such Closing Net Cash (the "<u>Additional Closing Net Cash Period</u>"). 

&nbsp;&nbsp;&nbsp;&nbsp;• **There is a risk that you may receive no payments under the CVR Agreement. Therefore, in making a decision to tender your Shares, you should understand that if the CVR does not generate any payments, the only consideration that you would receive is the Cash Amount of $1.247 per Share that is being offered pursuant to the Offer. You should base your tender decision on the Cash Amount as it may be the only consideration you receive in the Offer.** See the Introduction and " <u>The Tender Offer—Section 1. Terms of the Offer</u>."

#### WILL I HAVE TO PAY ANY FEES OR COMMISSIONS?
&nbsp;&nbsp;&nbsp;&nbsp;• If your Shares are registered in your name and you tender your Shares, you will not be obligated to pay brokerage fees or commissions or similar expenses. If you hold your Shares through a broker, dealer, commercial bank, trust company or other nominee and your broker, dealer, commercial bank, trust company or other nominee tenders your Shares on your behalf, your broker, dealer, commercial bank, trust company or other nominee may charge a fee for doing so. You should consult your broker, dealer, commercial bank, trust company or other nominee to determine whether any charges will apply. See the Introduction and " <u>The Tender Offer—Section 3. Procedures for Tendering Shares</u>."

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#### WHAT IS THE CVR AND HOW DOES IT WORK?
&nbsp;&nbsp;&nbsp;&nbsp;• At or prior to the Offer Closing Time, Parent, Merger Sub, the rights agent (the " <u>Rights Agent</u> ") and the representative of the holders of the CVRs (the " <u>Representative</u> ") will enter into the CVR Agreement governing the terms of the CVRs. Each CVR will represent a contractual right to receive contingent cash payments equal to a pro rata share of any Disposition Proceeds and Additional Closing Net Cash Proceeds, each as described above and pursuant to the CVR Agreement.

&nbsp;&nbsp;&nbsp;&nbsp;• Any Disposition Proceeds would be calculated and payable based on the distribution of Net Proceeds from Dispositions. We cannot predict whether any Dispositions will occur at all, or at what price they may be effected. Net Proceeds would depend upon various unknown factors, including market conditions, the identification of potential acquirers, the conclusions reached by potential acquirers after conducting due diligence with respect to the CVR Products or the Company Patents, and Parent and Merger Sub's ability to negotiate and consummate Dispositions with such third parties.

&nbsp;&nbsp;&nbsp;&nbsp;• Any Additional Closing Net Cash Proceeds would be calculated and payable based on the realization of any net savings equal to the amount by which the Closing Net Cash as finally determined pursuant to the Merger Agreement exceeds $82,000,000, adjusted for any claims Parent reasonably determines to be valid five (5) business days prior to the Merger Closing Date that are not accounted for in such Closing Net Cash. We cannot predict whether any net savings will be realized at all, or to what extent. Net savings would depend upon various unknown factors, including unforeseen claims and costs that IGM may incur.

&nbsp;&nbsp;&nbsp;&nbsp;• In connection with the Offer, none of the co-offerors engaged any independent valuation firm to conduct an analysis of the potential value of the CVR Products or received any material non-public information assessing the value of the CVR Products.

**Accordingly, in making a decision to tender your Shares in the Offer, you should understand that there can be no assurance that: (i) we will be able to consummate a sale, transfer, license or other disposition or grant of rights by Parent or any of its affiliates, including IGM after the Merger, of all or any part of the CVR Products or the Company Patents, or that such dispositions, if any, will generate Disposition Proceeds; or (ii) IGM will be able to realize any net savings versus the Closing Net Cash to generate any Additional Closing Net Cash Proceeds. You should also understand that, as discussed below, the co-offerors estimate that the amount that will be payable under the CVRs is most likely between $0.00–$0.02 per CVR, consisting of: (i) $0.00 per CVR in Disposition Proceeds; and (ii) $0.00–$0.02 per CVR in Additional Closing Net Cash Proceeds. However, this range of values is based on estimates and assumptions regarding future events, as more fully described below, and there is no guarantee that any payment will be made to holders of the CVRs, and, thus, for purposes of determining whether to tender your Shares in the Offer you should assume that no payment will be made under the CVR Agreement and the only consideration paid by the co-offerors will be the Cash Amount of $1.247 per Share.** 

&nbsp;&nbsp;&nbsp;&nbsp;• During the Disposition Period, Parent shall, and shall cause Merger Sub, licensees and rights transferees to use commercially reasonable efforts to: (i) enter into one or more agreements providing for a sale, transfer, license or other disposition or grant of rights of all or any part of the CVR Products or the Company Patents (each a " <u>Disposition Agreement</u> ") as soon as practicable following the Effective Time; (ii) retain an employee or consultant of Parent or Merger Sub for the purpose of maintaining and preserving the CVR Products and Company Patents (as defined in the CVR Agreement) and seeking, negotiating and executing Disposition Agreements; (iii) maintain the CVRs (including fees and expenses related to the Rights Agent and the Representative); (iv) maintain and prosecute the intellectual property relating to the CVR Products and Company Patents; and (v) continue the CMC Activities (as defined in the Merger Agreement) of the CVR Products to the extent the costs associated with such CMC Activities were included in the Closing Net Cash Schedule. For the avoidance of doubt, Parent and Merger Sub are not obligated to pursue new clinical, manufacturing or enabling work with respect to the CVR Products.

&nbsp;&nbsp;&nbsp;&nbsp;• The CVR holders will have no greater rights against Parent under the CVR Agreement, or the Guarantor under the Limited Guaranty, than those of general unsecured creditors of Parent or the Guarantor, as applicable, including in the event of any bankruptcy. The CVRs would be effectively

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junior in right of payment to all of Parent's and the Guarantor's secured obligations to the extent of the collateral securing such obligations, and the CVRs would be pari passu with all of Parent's and the Guarantor's unsecured obligations, including trade payables, pursuant to the CVR Agreement and the Limited Guaranty, as applicable. The Guarantor's obligation with respect to the CVRs under the Limited Guaranty is subject to a cap of an amount equivalent to the CVR Proceeds under the CVR Agreement.

&nbsp;&nbsp;&nbsp;&nbsp;• It is currently anticipated that up to an aggregate of 62,655,883 CVRs will be issued, representing CVRs to be issued as part of the consideration for each of the issued and outstanding Shares, as well as Shares underlying each outstanding In-the-Money Option, Company Restricted Stock Unit and Company Pre-Funded Warrant immediately prior to the Effective Time. For more information regarding the CVR Agreement, see " <u>The Tender Offer—Section 7. Summary of the Merger Agreement and</u> <u>Certain Other Agreements</u>."

#### IS IT POSSIBLE THAT NO PAYMENTS WILL BE PAYABLE TO THE HOLDERS OF CONTINGENT VALUE RIGHTS IN RESPECT OF SUCH CONTINGENT VALUE RIGHTS?
&nbsp;&nbsp;&nbsp;&nbsp;• Yes. You will only receive payments with respect to your CVRs upon:

(i) the receipt of Net Proceeds by Parent or any of its affiliates, including IGM after the Merger, from any sale, transfer, license or other disposition or grant of rights of all or any part of the CVR Products or the Company Patents by Parent or any of its affiliates, including IGM after the Merger, that occurs within the period beginning on the Merger Closing Date (as defined in the Merger Agreement) and ending on the first (1st) anniversary following the Merger Closing Date, and such Gross Proceeds are received by or otherwise due to Parent or any of its Affiliates by the first (1<sup>st</sup>) anniversary following the Merger Closing Date; and 

(ii) the realization of any net savings equal to the amount by which the Closing Net Cash as finally determined pursuant to the Merger Agreement exceeds $82,000,000, adjusted for any claims Parent reasonably determines to be valid five (5) business days prior to the Merger Closing Date that are not accounted for in such Closing Net Cash. 

&nbsp;&nbsp;&nbsp;&nbsp;• **The co-offerors estimate that the amount that will be payable under the CVRs is most likely between $0.00–$0.02 per CVR, consisting of: (i) $0.00 per CVR in Disposition Proceeds; and (ii) $0.00–$0.02 per CVR in Additional Closing Net Cash Proceeds. However, this range of values is based on estimates and assumptions regarding future events, as more fully described below, and there is no guarantee that any payment will be made to holders of the CVRs, and, thus, for purposes of determining whether to tender your Shares in the Offer you should assume that no payment will be made under the CVR Agreement and the only consideration paid by the co-offerors will be the Cash Amount of $1.247 per Share.** 

&nbsp;&nbsp;&nbsp;&nbsp;• *Disposition Proceeds*: The co-offerors' estimate of the amount that will be payable under the CVRs with respect to the Disposition Proceeds is based on the co-offerors' assessment of the CVR Products and their experience operating and investing in biotechnology companies and co-offerors' independent research. The CVR Products are early-stage product candidates for which there are no current plans to further advance in development. Further, there is uncertainty regarding co-offerors' ability to attract a potential acquirer for the CVR Products. Even if co-offerors were to be successful in negotiating transaction terms with a potential acquirer of the CVR Products, the transaction may include future development, regulatory or commercial milestone payments, thus, there is uncertainty regarding whether any potential acquirer of the CVR Products would be able to: (i) initiate and complete successful nonclinical studies and clinical trials for any product related to or based upon the CVR Products; (ii) conduct sufficient clinical trials or other studies to support the approval and commercialization of any product related to the CVR Products; (iii) demonstrate to the satisfaction of the U.S. Food and Drug Administration and similar foreign regulatory authorities the safety and efficacy and acceptable risk-to-benefit profile of any product related to the CVR Products; (iv) seek and obtain regulatory marketing approvals for any product related to the CVR Products; (v) establish and maintain supply and manufacturing relationships with third parties to ensure adequate and legally compliant manufacturing of bulk drug substances and drug products to maintain that supply, (vi) launch and commercialize any product candidates that were to obtain marketing approval and, if launched,

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successfully establish a sales, marketing and distribution infrastructure; (vii) demonstrate the necessary safety data post-approval to ensure continued regulatory approval; (viii) demonstrate the actual and perceived benefits of any product related to the CVR Products, if approved, relative to existing and future alternative therapies based upon availability, cost, risk and safety profile, drug-drug interactions, ease of administration, side effects and efficacy; (ix) obtain coverage and adequate product reimbursement from third-party payors, including government payors; (x) achieve market acceptance for any approved products; (xi) address any competing technological and market developments; (xii) negotiate favorable terms in any collaboration, licensing or other arrangements into which such acquirer may enter in the future and perform its obligations under such collaborations; (xiii) establish, maintain, protect and enforce intellectual property rights related to the CVR Products; or (xiv) attract, hire and retain qualified personnel, among other unknowns.

&nbsp;&nbsp;&nbsp;&nbsp;• *Additional Closing Net Cash Proceeds*: The co-offerors' estimate of the amount that will be payable under the CVRs with respect to the Additional Closing Net Cash Proceeds is based on co-offerors' current assessment of projected Closing Net Cash as of the Merger Closing Date, adjusted for any claims reasonably determined to be valid by Parent five (5) business days prior to the Merger Closing Date that are not accounted for in such Closing Net Cash. For example, and for illustrative purposes only, if the Closing Net Cash as finally determined in accordance with the Merger Agreement is estimated to be $83,250,000, and there are no adjustments for claims that are reasonably determined to be valid five (5) business days prior to the Merger Closing Date, then the Closing Net Cash in excess of $82,000,000 would be $1,250,000, or approximately $0.02 per CVR.

&nbsp;&nbsp;&nbsp;&nbsp;• **In considering whether to tender your Shares in the Offer, you should consider that it is entirely possible that no cash will be distributed to the holders of the CVRs under the terms of the CVR Agreement**.

&nbsp;&nbsp;&nbsp;&nbsp;• **For more information regarding the CVR Agreement, see "The Tender Offer—Section 7. Summary of the Merger Agreement and Certain Other Agreements."** 

#### MAY I TRANSFER MY CONTINGENT VALUE RIGHT?
&nbsp;&nbsp;&nbsp;&nbsp;• The CVRs will not be transferable except: (a) upon death of the holder by will or intestacy; (b) pursuant to a court order; (c) by operation of law (including by consolidation or merger) or without consideration in connection with the dissolution, liquidation or termination of any corporation, limited liability company, partnership or other entity; (d) in the case of CVRs held in book-entry or other similar nominee form, from a nominee to a beneficial owner and, if applicable, through an intermediary, to the extent allowable by the Depository Trust Company (" <u>DTC</u> "); or (e) that CVRs may be abandoned, as provided under Section 2.7 of the CVR Agreement. For more information regarding the CVR Agreement, see " <u>The Tender Offer—Section 7. Summary of the Merger Agreement</u> <u>and Certain Other Agreements</u>."

#### ARE THERE OTHER MATERIAL TERMS OF THE CONTINGENT VALUE RIGHTS?
&nbsp;&nbsp;&nbsp;&nbsp;• In addition to the terms and conditions described above, the CVRs will not have any voting or dividend rights and will not represent any equity or ownership in Parent, any constituent corporation party to the Merger or any of its affiliates. No interest will accrue or become payable in respect of any of the amounts that may become payable on the CVRs. For more information regarding the CVR Agreement, see " <u>The</u> <u>Tender Offer—Section 7. Summary of the Merger Agreement and Certain Other Agreements</u>."

#### WHY IS PURCHASER MAKING THE OFFER?
&nbsp;&nbsp;&nbsp;&nbsp;• Purchaser has undertaken to acquire control of, and the entire equity interest in, IGM because it believes it is a good investment. See " <u>Special Factors—Section 2. Purpose of the Offer and Plans for</u> <u>IGM</u> " and " <u>The Tender Offer—Section 1. Terms of the Offer</u>."

#### WHAT ARE THE MOST SIGNIFICANT CONDITIONS OF THE OFFER?
&nbsp;&nbsp;&nbsp;&nbsp;• Pursuant to the Merger Agreement, Purchaser's obligation to accept Shares tendered in the Offer is subject to the satisfaction or waiver of certain conditions. Purchaser will not be required to accept for payment or,

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subject to any applicable rules and regulations of the Securities and Exchange Commission ("SEC"), including Rule 14e-1(c) under the Securities Exchange Act of 1934, as amended (the "<u>Exchange Act</u>") (relating to Purchaser's obligation to pay for or return tendered Shares promptly after the termination or withdrawal of the Offer), pay for any Shares tendered pursuant to the Offer and, subject to the terms of the Merger Agreement, may delay the acceptance for payment of or payment for Shares or may terminate or amend the Offer, if:

(a) prior to the Expiration Date, there shall not have been validly tendered (and not properly withdrawn) at least one voting Share more than 50% of the number of voting Shares that are then issued and outstanding as of the expiration of the Offer (the "<u>Minimum Tender Condition</u>"); or 

(b)<br> any of the following conditions exist or shall have occurred and be continuing at the Expiration Date:

(i)<br> there shall be any Legal Restraint (as defined in the Merger Agreement) in effect preventing or prohibiting the consummation of the Offer, the Merger or any of the other transactions contemplated by the Merger Agreement or CVR Agreement;

(ii) (A) (1) any representation or warranty of IGM set forth in Article IV of the Merger Agreement (other than those set forth in Section 4.01 (Organization, Standing and Power) (but only with respect to the first and second sentences thereof), Section 4.02 (Capital Structure), Section 4.04 (Authority; Execution and Delivery; Enforceability), Section 4.05(a)(i) (No Conflicts; Consents), Section 4.08(a) (No Material Adverse Effect), Section 4.20 (Brokers and Other Advisors), Section 4.22 (Opinion of Financial Advisors) and Section 4.23 (No Vote Required)) shall not be true and correct as of the Agreement Date and at and as of the Offer Closing Time as if made on and as of the Offer Closing Time, except to the extent such representation or warranty expressly relates to a specified date (in which case on and as of such specified date), other than for such failures to be true and correct that have not had or would not reasonably be expected to have, individually or in the aggregate, a Company Material Adverse Effect (as defined below) (for purposes of determining the satisfaction of this condition, without regard to any qualifications or exceptions contained therein as to "materiality" or "Company Material Adverse Effect"), (2) any representation or warranty of IGM set forth in Section 4.01 (Organization, Standing and Power) (but only with respect to the first and second sentences thereof), Section 4.02<u>(a)</u>, <u>(b)</u>, <u>(c)</u>, <u>(d)</u>, <u>(e)</u>, (f) and (g) (Capital Structure), Section 4.04 (Authority; Execution and Delivery; Enforceability), Section 4.05(a)(i) (No Conflicts), Section 4.20 (Brokers and other Advisors), Section 4.22 (Opinion of Financial Advisors), Section 4.23 (No Vote Required), and the Closing Net Cash Schedule (as defined in the Merger Agreement) shall not be true and correct in all material respects as of the Agreement Date and at and as of the Offer Closing Time as if made on and as of the Offer Closing Time, except to the extent such representation or warranty expressly relates to a specified date (in which case on and as of such specified date), (3) any representation or warranty of IGM set forth in Section 4.02(a) (Capital Structure) of the Merger Agreement shall not be true and correct other than in de minimis respects at and as of such time, except to the extent such representation or warranty expressly relates to a specified date (in which case on and as of such specified date) and (4) any representation or warranty of IGM set forth in Section 4.08(a) (No Material Adverse Effect) of the Merger Agreement shall not be true and correct in all respects as of such time; 

(iii)<br> IGM shall have failed to perform in all material respects the obligations to be performed by it as of such time under the Merger Agreement, including without limitation IGM's obligations under Section 6.02 of the Merger Agreement;

(iv) Parent shall have failed to receive from IGM a certificate, dated as of the date on which the Offer expires and signed by an executive officer of IGM, certifying to the effect that the Offer Conditions set forth in clauses (ii) and (iii) have been satisfied as of immediately prior to the expiration of the Offer; 

(v)<br> the Merger Agreement shall have been validly terminated in accordance with its terms (the "<u>Termination Condition</u>"); or

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(vi) the Closing Net Cash (as defined in the Merger Agreement) as finally determined pursuant to <u>Section 2.01(d)</u> of the Merger Agreement is less than $82,000,000 (the "<u>Minimum Cash</u> <u>Condition</u>"). 

Purchaser reserves the right to waive certain of the conditions to the Offer in their sole discretion (including the Minimum Cash Condition); provided that they may not waive the Minimum Tender Condition or the Termination Condition. The Minimum Cash Condition is subject to Closing Net Cash equal to or greater than $82,000,000.

A more detailed discussion of the conditions to consummation of the Offer is contained in the Introduction, "<u>The Tender Offer—Section 1. Terms of the Offer</u>" and "<u>The Tender Offer—Section 9. Conditions of the</u> <u>Offer</u>."

#### IS THERE AN AGREEMENT GOVERNING THE OFFER?
&nbsp;&nbsp;&nbsp;&nbsp;• Yes. IGM, Parent and Merger Sub have entered into the Merger Agreement. The Merger Agreement provides, among other things, for the terms and conditions of the Offer and, following consummation of the Offer, the Merger. See " <u>The Tender Offer—Section 7. Summary of the Merger Agreement and</u> <u>Certain Other Agreements</u>." Additionally, the obligations of Parent and Merger Sub under the Merger Agreement have been guaranteed by the Guarantor pursuant to the Limited Guaranty, subject to the terms and conditions set forth therein.

#### DOES PARENT HAVE FINANCIAL RESOURCES TO MAKE PAYMENTS IN THE OFFER AND, IF REQUIRED, IN RESPECT OF THE CVRS?
&nbsp;&nbsp;&nbsp;&nbsp;• Yes. Purchaser expects: (i) to pay cash consideration for all Shares accepted for payment in the Offer, and (ii) any payments of CVR Proceeds, if any, will be self-funded with: (a) 80% of the Net Proceeds, if any, from any sale, transfer, license or other disposition or grant of rights by Parent or any of its affiliates, including IGM after the Merger, of all or any part of the CVR Products or the Company Patents (described above) that occurs within the period beginning on the Merger Closing Date (as defined in the Merger Agreement) and ending on the first (1<sup>st</sup>) anniversary following the Merger Closing Date, and such Gross Proceeds are received by or otherwise due to Parent or any of its Affiliates by the first (1<sup>st</sup>) anniversary following the Merger Closing Date; and (b) 100% of the Closing Net Cash in excess $82,000,000, adjusted for any claims Parent reasonably determines to be valid five (5) business days prior to the Merger Closing Date that are not accounted for in such Closing Net Cash, each pursuant to the CVR Agreement.

&nbsp;&nbsp;&nbsp;&nbsp;• In addition, in connection with the execution of the Merger Agreement, the Guarantor agreed to guarantee certain of Parent's and Merger Sub's obligations under the Merger Agreement and certain Parent's obligations under the CVR Agreement, subject to the terms and conditions set forth in the Limited Guaranty. The Guarantor's obligations under the Limited Guaranty are subject to a cap of $78,000,000, which includes certain Enforcement Costs, under the Merger Agreement and an amount equivalent to the CVR Proceeds under the CVR Agreement. See " <u>Special Factors—Section 2. Purpose</u> <u>of the Offer and Plans for IGM</u> " " <u>The Tender Offer—Section 7. Summary of the Merger Agreement</u> <u>and Certain Other Agreements</u> " and " <u>The Tender Offer—Section 8. Source and Amount of Funds</u>."

#### SHOULD PURCHASER'S FINANCIAL CONDITION BE RELEVANT TO MY DECISION TO TENDER IN THE OFFER?
&nbsp;&nbsp;&nbsp;&nbsp;• No. Purchaser's financial condition is not relevant to your decision to tender in the Offer because: (i) the form of payment consists solely of cash; (ii) any payments of CVR Proceeds will be self-funded (as described above); (iii) the Offer is not subject to any financing conditions; (iv) the Offer is for all outstanding Shares of IGM; and (v) the Purchaser does not have any relevant historical information. See " <u>The Tender Offer—Section 8. Source and Amount of Funds</u>."

&nbsp;&nbsp;&nbsp;&nbsp;• In addition, in connection with the execution of the Merger Agreement, the Guarantor agreed to guarantee certain of Parent's and Merger Sub's obligations under the Merger Agreement and certain of Parent's obligations under the CVR Agreement, subject to the terms and conditions set forth in the Limited Guaranty. The Guarantor's obligations under the Limited Guaranty are subject to a cap of $78,000,000, which includes certain Enforcement Costs, under the Merger Agreement and an amount equivalent to the CVR Proceeds under the CVR Agreement.

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#### HOW LONG DO I HAVE TO DECIDE WHETHER TO TENDER IN THE OFFER?
&nbsp;&nbsp;&nbsp;&nbsp;• You will have until one minute after 11:59 p.m. Eastern Time on August 13, 2025, to tender your Shares in the Offer, unless Purchaser extends the Offer, in which event you will have until the Expiration Date of the Offer as so extended. See also " <u>The Tender Offer—Section 1. Terms of the Offer</u>."

#### CAN THE OFFER BE FURTHER EXTENDED, AND UNDER WHAT CIRCUMSTANCES?
&nbsp;&nbsp;&nbsp;&nbsp;• Yes, the Offer can be extended. We have agreed in the Merger Agreement, subject to our rights to terminate the Merger Agreement in accordance with its terms, if on any then-scheduled expiration of the Offer the Minimum Tender Condition has not been satisfied or any Offer Condition (as defined in the Merger Agreement) has not been satisfied or waived by Purchaser (set forth in " <u>The Tender</u> <u>Offer—Section 9. Conditions of the Offer</u> "), Purchaser may, in its discretion, or at the request of IGM, Purchaser shall, extend the Offer: (i) for periods of up to 10 business days per extension to permit such Offer Condition to be satisfied; or (ii) for any period required by any rule, regulation, interpretation or position of the SEC or the staff thereof or the rules of The Nasdaq Global Select Market (" <u>Nasdaq</u> ") applicable to the Offer; provided, that, Purchaser shall not, and shall not be required to, extend the Offer beyond September 29, 2025 (the " <u>Outside Date</u> ").

#### HOW WILL I BE NOTIFIED IF THE OFFER IS FURTHER EXTENDED?
&nbsp;&nbsp;&nbsp;&nbsp;• If Purchaser further extends the Offer, we will inform Broadridge Corporate Issuer Solutions, LLC, the depositary and paying agent for this Offer (the " <u>Depositary and Paying Agent</u> "), of that fact and will file with the SEC and disseminate to the holders of Shares, as and to the extent required by law, a supplement or amendment to this Offer to Purchase giving the new Expiration Date no later than 9:00 a.m. Eastern Time on the next business day after the day on which the Offer was previously scheduled to expire. See " <u>The Tender Offer—Section 1. Terms of the Offer</u>."

#### HOW DO I TENDER MY SHARES?
&nbsp;&nbsp;&nbsp;&nbsp;• If you hold your Shares directly as the registered owner, you can tender your Shares in the Offer by delivering the certificates (if any) representing your Shares, together with a completed Letter of Transmittal and any other documents required by the Letter of Transmittal, to the Depositary and Paying Agent not later than the expiration of the Offer. See " <u>The Tender Offer—Section 3. Procedures</u> <u>for Tendering Shares</u>." The Letter of Transmittal is enclosed with this Offer to Purchase.

&nbsp;&nbsp;&nbsp;&nbsp;• If you hold your Shares in street name (*i.e.*, through a broker, dealer, commercial bank, trust company or other nominee), you must contact the institution that holds your Shares and give instructions that your Shares be tendered. You should contact the institution that holds your Shares for more details.

&nbsp;&nbsp;&nbsp;&nbsp;• In all cases, payment for tendered Shares will be made only after timely receipt by the Depositary and Paying Agent of certificates (if any) for such Shares and a properly completed and duly executed Letter of Transmittal and any other required documents for such Shares (or an Agent's Message in lieu of the Letter of Transmittal in the case of a book-entry transfer of such Shares as described in " <u>The Tender</u> <u>Offer—Section 3. Procedures for Tendering Shares</u> "). See also " <u>The Tender Offer—Section 2.</u> <u>Acceptance for Payment and Payment for Shares</u>."

#### UNTIL WHAT TIME CAN I WITHDRAW PREVIOUSLY TENDERED SHARES?
&nbsp;&nbsp;&nbsp;&nbsp;• You may withdraw previously tendered Shares any time prior to one minute after 11:59 p.m. Eastern Time on August 13, 2025, unless Purchaser extends the Offer. See " <u>The Tender Offer—Section 4.</u> <u>Withdrawal Rights</u>."

&nbsp;&nbsp;&nbsp;&nbsp;• In addition, pursuant to Section 14(d)(5) of the Securities Exchange Act of 1934, as amended, Shares may be withdrawn at any time after September 14, 2025, which is the 60<sup>th</sup> day after the date of the commencement of the Offer, unless such Shares have already been accepted for payment by Purchaser pursuant to the Offer.

#### HOW DO I WITHDRAW PREVIOUSLY TENDERED SHARES?
&nbsp;&nbsp;&nbsp;&nbsp;• To withdraw previously tendered Shares, you must deliver a written notice of withdrawal with the required information to the Depositary and Paying Agent while you still have the right to withdraw.

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If you tendered Shares by giving instructions to a broker, dealer, commercial bank, trust company or other nominee, you must instruct the broker, dealer, commercial bank, trust company or other nominee to arrange for the withdrawal of your Shares. See "<u>The Tender Offer—Section 4. Withdrawal Rights</u>."

#### WHAT DOES IGM'S BOARD OF DIRECTORS THINK OF THE OFFER?
&nbsp;&nbsp;&nbsp;&nbsp;• After careful consideration, the IGM board of directors (the " <u>IGM Board</u> "), duly recommended that you accept the Offer. IGM's full statement on the Offer is set forth in its Solicitation/Recommendation Statement on Schedule 14D-9, which it will file with the SEC on July 16, 2025. See also the " <u>Introduction</u> " below.

#### WILL THE TENDER OFFER BE FOLLOWED BY A MERGER IF ALL THE SHARES ARE NOT TENDERED?
&nbsp;&nbsp;&nbsp;&nbsp;• If we accept Shares for payment pursuant to the Offer, then the Minimum Tender Condition will have been satisfied and we will hold a sufficient number of Shares to effect the Merger without a vote by IGM stockholders under the General Corporation Law of the State of Delaware (the " <u>DGCL</u> "). If the Merger occurs, then IGM will become a wholly owned subsidiary of Parent and each issued and then outstanding Share, other than Shares held in the treasury by IGM, held by any stockholders, or owned by any beneficial owners, of IGM who are entitled to and who properly exercise appraisal rights under Delaware law or owned by Parent, Merger Sub or any other subsidiary of Parent at the commencement of the Offer and is owned by Parent, Merger Sub or any other subsidiary of Parent immediately prior to the Effective Time, will be converted into the right to receive the Offer Price, without interest and subject to any applicable tax withholding. For more information, see the " <u>Introduction</u> " below.

&nbsp;&nbsp;&nbsp;&nbsp;• Because the Merger will be governed by Section 251(h) of the DGCL, no stockholder vote will be required to consummate the Merger. As required by Section 251(h) of the DGCL, the Merger Agreement provides that the Merger shall be effected as soon as practicable following the time Purchaser first irrevocably accepts for purchase the Shares tendered in the Offer (the " <u>Offer Closing</u> <u>Time</u> "). See " <u>Special Factors—Section 2. Purpose of the Offer and Plans for IGM</u> " and " <u>The Tender</u> <u>Offer—Section 7. Summary of the Merger Agreement and Certain Other Agreements</u>."

#### IF THE OFFER IS COMPLETED, WILL IGM CONTINUE AS A PUBLIC COMPANY?
&nbsp;&nbsp;&nbsp;&nbsp;• No. Immediately following the Offer Closing Time and satisfaction or waiver (to the extent permitted by applicable law) of the conditions to the Merger, we expect to complete the Merger pursuant to applicable provisions of the DGCL, after which the Surviving Corporation will be a wholly owned subsidiary of Parent, and the Shares will be delisted from Nasdaq, and IGM's obligations to file periodic reports under the Exchange Act will be suspended, and IGM will be privately held. See " <u>Special Factors—Section 5. Possible Effects of the Offer on the Market for the Shares; Nasdaq</u> <u>Listing; Exchange Act Registration and Margin Regulations</u>."

#### IF I DECIDE NOT TO TENDER, HOW WILL THE OFFER AFFECT MY SHARES?
&nbsp;&nbsp;&nbsp;&nbsp;• If you decide not to tender your Shares in the Offer and the Merger occurs as described above, you will receive in the Merger the right to receive the Offer Price as if you had tendered your Shares in the Offer, unless an appraisal demand is made with respect to your Shares.

&nbsp;&nbsp;&nbsp;&nbsp;• If you decide not to tender your Shares in the Offer and the Merger does not occur, you will remain a stockholder of IGM. Subject to limited conditions, if we purchase Shares in the Offer, we are obligated under the Merger Agreement to cause the Merger to occur. See " <u>Special Factors—Section 5. Possible</u> <u>Effects of the Offer on the Market for the Shares; Nasdaq Listing; Exchange Act Registration and</u> <u>Margin Regulations</u>."

&nbsp;&nbsp;&nbsp;&nbsp;• Following the Offer Closing Time, the Shares may no longer constitute "margin securities" for purposes of the margin regulations of the Federal Reserve Board, in which case your Shares may no longer be used as collateral for loans made by brokers. See " <u>Special Factors—Section 5. Possible</u> <u>Effects of the Offer on the Market for the Shares; Nasdaq Listing; Exchange Act Registration and</u> <u>Margin Regulations</u>."

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#### WHAT IS THE MARKET VALUE OF MY SHARES AS OF A RECENT DATE?
&nbsp;&nbsp;&nbsp;&nbsp;• On July 15, 2025, the last full trading day prior to the date of this Offer to Purchase, the last reported closing price per Share reported on Nasdaq was $1.35. See " <u>Special Factors—Section 4. Price Range</u> <u>of Shares; Dividends</u>."

#### IF I ACCEPT THE OFFER, WHEN AND HOW WILL I GET PAID?
&nbsp;&nbsp;&nbsp;&nbsp;• If the conditions to the Offer as set forth in the Introduction and " <u>The Tender Offer—Section 9.</u> <u>Conditions of the Offer</u> " are satisfied or waived and Purchaser consummates the Offer and accepts your Shares for payment, we will pay you a dollar amount in cash equal to the number of Shares you tendered multiplied by the Cash Amount, plus one CVR for each Share, in each case, without interest and subject to any applicable tax withholding, promptly following the time at which Purchaser accepts for payment Shares tendered in the Offer (and in any event within three business days). See " <u>The</u> <u>Tender Offer—Section 1. Terms of the Offer</u> " and " <u>The Tender Offer—Section 2. Acceptance for</u> <u>Payment and Payment for Shares</u>."

&nbsp;&nbsp;&nbsp;&nbsp;• We will pay to the holders of CVRs: (a) with respect to Disposition Proceeds payable to Holders, no later than thirty (30) days following the receipt of Gross Proceeds by Parent or any of its affiliates; and (b) with respect to any Additional Closing Net Cash Proceeds payable to Holders, no later than five (5) days following the Merger Closing Date.

&nbsp;&nbsp;&nbsp;&nbsp;• For more information regarding the CVR Agreement, see " <u>The Tender Offer—Section 7. Summary of</u> <u>the Merger Agreement and Certain Other Agreements</u>."

#### IF I AM AN EMPLOYEE OF IGM, HOW WILL MY OUTSTANDING EQUITY AWARDS BE TREATED IN THE OFFER AND THE MERGER?
&nbsp;&nbsp;&nbsp;&nbsp;• As of immediately prior to the Effective Time, the vesting for each Company Stock Option and, as of immediately prior to the Offer Closing Time, the vesting for each Company Restricted Stock Unit, shall be accelerated and: (i) (A) each Company Stock Option that has an exercise price per share that is less than the Cash Amount (each, an " <u>In-the-Money Option</u> ") that is then outstanding will be cancelled and, in exchange therefor, the holder of such cancelled In-the-Money Option will be entitled to receive in consideration of the cancellation of such In-the-Money Option (1) an amount in cash without interest, less any applicable tax withholding, equal to the product obtained by multiplying (x) the excess of the Cash Amount over the exercise price per share of Shares underlying such In-the-Money Option by (y) the number of Shares underlying such In-the-Money Option as of immediately prior to the Effective Time, and (2) one CVR for each Share subject thereto, and (B) each Company Stock Option that has an exercise price per share that is equal to or greater than the Cash Amount that is then outstanding will be cancelled for no consideration; and (ii) each Company Restricted Stock Unit that is then outstanding will be cancelled and, in exchange therefor, the holder of such cancelled Company Restricted Stock Unit will be entitled to receive in consideration of the cancellation of such Company Restricted Stock Unit (A) an amount in cash without interest, less any applicable tax withholding, equal to the Cash Amount, and (B) one CVR.

**WHAT ARE THE PRINCIPAL U.S. FEDERAL INCOME TAX CONSEQUENCES OF TENDERING MY SHARES IN THE OFFER OR HAVING MY SHARES EXCHANGED FOR THE OFFER PRICE PURSUANT TO THE MERGER?** 

&nbsp;&nbsp;&nbsp;&nbsp;• The receipt of cash and CVRs in exchange for Shares pursuant to the Offer or the Merger will generally be treated for U.S. federal income tax purposes as consideration received in a "sale or exchange" of the Shares that you exchange in the Offer or the Merger. The amount of income, gain or loss a holder recognizes, and the timing and character of such income, gain or loss will depend on the U.S. federal income tax treatment of the CVRs, with respect to which there is uncertainty. We intend to treat the receipt of the CVRs as part of a "closed transaction" for U.S. federal income tax purposes and to treat payments received pursuant to the CVRs as amounts realized on the disposition (or partial disposition) of the CVRs. Assuming such treatment is respected by the Internal Revenue Service (" <u>IRS</u> "), a U.S. Holder (as defined below in " <u>Special</u> <u>Factors—Section</u> <u>6. Material</u> <u>U.S. Federal Income Tax Consequences of the Offer and the Merger</u> ") is expected to recognize gain or loss equal to the difference, if any, between: (i) the sum of the Cash Amount received plus the fair market value (determined as of the closing of the Offer or the Effective Time, as the

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case may be) of any CVRs received; and (ii) the U.S. Holder's adjusted tax basis in the Shares sold or exchanged. The tax treatment of the receipt of the payments pursuant to the CVRs is also uncertain. We urge you to consult your own tax advisor as to the particular tax consequences to you of the Offer and the Merger (including the application and effect of any state, local or non-U.S. income and other tax laws). See "<u>Special Factors—Section</u> <u>6</u><u>. Material U.S. Federal Income Tax Consequences of the Offer and the Merger</u>" for a more detailed discussion of material U.S. federal income tax consequences of the Offer and the Merger.

The U.S. federal, state, local and non-U.S. income and other tax consequences to holders or beneficial owners of Company Stock Options or Company Restricted Stock Units participating in the Merger with respect to such Company Stock Options or Company Restricted Stock Units are not discussed herein, and such holders or beneficial owners are strongly encouraged to consult with their own tax advisors.

#### WILL I HAVE THE RIGHT TO HAVE MY SHARES APPRAISED?
&nbsp;&nbsp;&nbsp;&nbsp;• No appraisal rights are available to the holders of record and beneficial owners of Shares in connection with the Offer, and stockholders who tender their Shares in the Offer will not have appraisal rights in connection with the Merger. However, if Purchaser purchases Shares in the Offer and the Merger is consummated, holders of record and beneficial owners of Shares outstanding as of immediately prior to the Effective Time who: (i) did not tender their Shares in the Offer (or, if tendered, validly and subsequently withdrew such Shares prior to the time Parent accepts properly tendered Shares for purchase); (ii) otherwise comply with the applicable procedures under Section 262 of the DGCL; and (iii) do not thereafter withdraw their demand for appraisal of such Shares or otherwise lose their appraisal rights, in each case in accordance with the DGCL, will be entitled to demand appraisal of their Shares and may be entitled to receive in lieu of the consideration payable in the Merger a cash payment equal to the "fair value" of their Shares, as determined by the Delaware Court of Chancery, in accordance with Section 262 of the DGCL plus interest, if any, on the amount determined to be the fair value.

&nbsp;&nbsp;&nbsp;&nbsp;• The "fair value" of the Shares as determined by the Delaware Court of Chancery could be based upon considerations other than, or in addition to, the price paid in the Offer and the Merger and the market value of such Shares. Persons considering appraisal should recognize that the value determined in an appraisal proceeding of the Delaware Court of Chancery could be higher or lower than, or the same as, the Offer Price and that an investment banking opinion as to the fairness, from a financial point of view, of the consideration payable in a sale transaction, such as the Offer and the Merger, is not an opinion as to, and does not otherwise address, fair value under the DGCL. Moreover, Parent and IGM may argue in an appraisal proceeding that, for purposes of such proceeding, the "fair value" of such Shares is less than the Offer Price.

&nbsp;&nbsp;&nbsp;&nbsp;• **Any person who desires to exercise appraisal rights in connection with the Merger should carefully review Section 262 of the DGCL and is urged to consult his, her or its legal advisor before electing or attempting to exercise such rights.** 

&nbsp;&nbsp;&nbsp;&nbsp;• The foregoing summary of appraisal rights under the DGCL does not purport to be a statement of the procedures to be followed by persons desiring to exercise any appraisal rights under Delaware law. The preservation and exercise of appraisal rights require strict and timely adherence to the applicable provisions of Delaware law, which are contained in Section 262 of the DGCL and will be further summarized in a notice of the availability of appraisal rights to be sent by IGM to each stockholder who is entitled to appraisal rights. The foregoing discussion is not a complete statement of law pertaining to appraisal rights under Delaware law and is qualified in its entirety by reference to Delaware law, including without limitation, Section 262 of the DGCL, a copy of which may be accessed without subscription or cost at the following publicly available website: https://delcode.delaware.gov/title8/c001/sc09/index.html#262. For more information regarding appraisal rights, see " <u>The Tender Offer—Section 11. Certain Legal Matters;</u> <u>Regulatory Approvals</u>."

&nbsp;&nbsp;&nbsp;&nbsp;• If you tender your Shares in the Offer, you will not be entitled to exercise appraisal rights with respect to your Shares but, instead, subject to the conditions of the Offer, you will receive the Offer Price for your Shares.

#### WITH WHOM MAY I TALK IF I HAVE QUESTIONS ABOUT THE OFFER?
&nbsp;&nbsp;&nbsp;&nbsp;• You may call MacKenzie Partners, Inc., the Information Agent for the Offer, toll-free at (800) 322-2885 or email them at tenderoffer@mackenziepartners.com. See the back cover of this Offer to Purchase.

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#### To All Holders of Shares of <br>

#### IGM Biosciences, Inc.

#### INTRODUCTION
Purchaser is making the Offer to acquire all outstanding Shares of IGM for: (i) $1.247 per Share in cash (the "<u>Cash Amount</u>"); and (ii) one non-transferable contractual contingent value right for each Share (each, a "<u>CVR</u>", and each CVR together with the Cash Amount, the "<u>Offer Price</u>") which represents the right to receive one or more contingent cash payments equal to a pro rata share of: (i) 80% of the net proceeds from a disposition of: (a) IGM's product candidates known as: (A) imvotamab, an IgM-based CD20 X CD3 bispecific antibody T cell engager; (B) IGM-2644, an IgM-based CD38 X CD3 bispecific T cell engager; (C) aplitabart (or IGM-8444), a Death Receptor 5 agonist; (D) IGM-7354, a targeted IL-15/IL-15R IgM antibody; (E) IGM-8447, an IgM-based Death Receptor 5 agonist; and (F) IGM-2537, an IgM-based CD123 X CD3 bispecific antibody T cell engager; or (b) patents and patent applications owned or controlled by the Company immediately prior to the closing of the Merger and set forth on Schedule 1 of the CVR Agreement, together with all patents issuing thereon or claiming priority thereto, in each case, that occurs within one (1) year following the Merger Closing Date, and such proceeds are received by or otherwise due to Parent or any of its Affiliates within one (1) year following the Merger Closing Date; and (ii) 100% of the Closing Net Cash in excess of $82,000,000, as determined five (5) business days prior to the Merger Closing Date, each pursuant to the CVR Agreement, in each case, all upon the terms and subject to the conditions described in this Offer to Purchase and in the related Letter of Transmittal. Subject to the terms of the Merger Agreement and the CVR Agreement, the Offer Price will be paid net of any applicable tax withholding and without interest.

The Offer is being made pursuant to the Merger Agreement among IGM, Parent and Merger Sub, pursuant to which, after the completion of the Offer and the satisfaction or waiver of certain conditions, Merger Sub will be merged with and into IGM, without a meeting or any further action of IGM stockholders in accordance with Section 251(h) of the DGCL, assuming the conditions set forth in Section 251(h) of the DGCL are met, and IGM will be the Surviving Corporation and a wholly owned subsidiary of Parent. Accordingly, Merger Sub is considered a co-offeror in the Offer. Upon the terms and subject to the satisfaction or waiver of the conditions of the Offer and the Merger Agreement, including the satisfaction of the Minimum Tender Condition, Purchaser will accept for payment and thereafter pay for all Shares validly tendered and not properly withdrawn pursuant to the Offer at the Offer Closing Time.

Concurrently with the execution of the Merger Agreement, and as a condition and inducement to IGM's willingness to enter into the Merger Agreement and the CVR Agreement, the Guarantor has duly executed and delivered to IGM the Limited Guaranty in favor of IGM and the holders of CVRs, in respect of certain obligations of Parent and Merger Sub under the Merger Agreement and certain obligations of IGM as the Surviving Corporation under the CVR Agreement. The Guarantor's obligations under the Limited Guaranty are subject to a cap of $78,000,000, which includes certain Enforcement Costs, under the Merger Agreement and an amount equivalent to the CVR Proceeds (as defined below) under the CVR Agreement. The Guarantor and TCM are considered co-offerors in the Offer. As co-offerors, TCP and TCM accept joint responsibility for the accuracy of the disclosures made in this Offer to Purchase.

**As noted in the Summary Term Sheet, there is a risk that you may receive no payments under the CVRs. Therefore, in making a decision to tender your Shares, you should understand that if the CVR does not generate any payments, the only consideration that you would receive is the Cash Amount of $1.247 per Share that is being offered pursuant to the Offer. You should base your tender decision on the Cash Amount as it may be the only consideration you receive in the Offer. On July 15, 2025, the last full trading day prior to the date of this Offer to Purchase, the closing price of IGM's common stock as reported on Nasdaq was $1.35 per Share.** 

If your Shares are registered in your name and you tender directly to the Depositary and Paying Agent, you will not be obligated to pay brokerage fees or commissions or, except as otherwise provided in Instruction 6 of the Letter of Transmittal, transfer taxes on the purchase of Shares by Purchaser pursuant to the Offer. If you hold your Shares through a broker, dealer, commercial bank, trust company or other nominee you should check with such institution as to whether they charge any service fees or commissions.

We will pay all charges and expenses of the Depositary and Paying Agent and the Information Agent.

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#### **TABLE OF CONTENTS**
**Purchaser shall not be required to accept for payment or, subject to any applicable rules and regulations of the SEC, including Rule 14e-1(c) under the Exchange Act (relating to Purchaser's obligation to pay for or return tendered Shares promptly after the termination or withdrawal of the Offer), to pay for any Shares tendered pursuant to the Offer and, subject to the terms of the Merger Agreement, may delay the acceptance for payment of or payment for Shares or may terminate or amend the Offer, if:** 

(i)<br> prior to the Expiration Date, the Minimum Tender Condition shall have not been satisfied; or

(ii)<br> any of the conditions set forth in "<u>The Tender Offer—Section 9. Conditions of the Offer</u>" shall exist or shall have occurred and be continuing at the Expiration Date of the Offer.

**Purchaser reserves the right to waive certain of the conditions to the Offer in their sole discretion (including the Minimum Cash Condition); provided that they may not waive the Minimum Tender Condition or the Termination Condition. See "<u>The Tender Offer—Section 9. Conditions of the Offer</u>."** 

**Pursuant to the terms of the Merger Agreement, the Offer and withdrawal rights will expire at one minute past 11:59 p.m. Eastern Time on August 13, 2025 (the "<u>Expiration Date</u>"). See "<u>The Tender Offer</u> <u>—Section 1. Terms of the Offer</u>," "<u>The Tender Offer—Section 9. Conditions of the Offer</u>" and "<u>The</u> <u>Tender Offer—Section 11. Certain Legal Matters; Regulatory Approvals</u>."** 

**On July 1, 2025, the IGM board of directors (the "<u>IGM Board</u>") at a duly called and held meeting, duly and by unanimous vote: (i) determined that the terms of the Merger Agreement, the Offer and the other transactions contemplated by the Merger Agreement and the CVR Agreement (collectively, the "<u>Transactions</u>") are advisable, fair to, and in the best interests of, IGM and IGM's stockholders; (ii) approved and declared advisable the Merger Agreement and the Transactions; (iii) authorized and approved the execution, delivery and performance by IGM of the Merger Agreement and the consummation by IGM of the Transactions; (iv) resolved to recommend that IGM's stockholders accept the Offer and tender their shares of IGM Common Stock in the Offer; and (v) resolved that the Merger Agreement and the Merger shall be governed by and effected under Section 251(h) of the DGCL and the Merger will be consummated as soon as practicable following the Offer Closing Time.** 

For reasons considered by the IGM Board, see IGM's Solicitation/Recommendation Statement on Schedule 14D-9 (the "<u>Schedule 14D-9</u>") filed with the SEC on July 16, 2025 in connection with the Offer, a copy of which (without certain exhibits) is being furnished to stockholders concurrently herewith.

The Offer is being made in connection with the Merger Agreement, pursuant to which, after the completion of the Offer and the satisfaction or waiver of certain conditions, the Merger will be effected. The Merger shall become effective when a certificate of merger is filed with the Secretary of State of the State of Delaware (or at such subsequent date and time as may be agreed by Parent, IGM and Merger Sub and specified in the certificate of merger).

Pursuant to the terms of the Merger Agreement, at the Effective Time, by virtue of the Merger and without any action on the part of the holders of Shares, each outstanding Share, other than Shares held in the treasury by IGM, held by any stockholders, or owned by any beneficial owners, of IGM who are entitled to and who properly exercise appraisal rights under Delaware law or owned by Parent, Merger Sub or any other subsidiary of Parent at the commencement of the Offer and is owned by Parent, Merger Sub or any other subsidiary of Parent immediately prior to the Effective Time, will be converted into the right to receive the Offer Price, without interest and subject to any applicable tax withholding. As of immediately prior to the Effective Time, the vesting for each option to purchase Shares from IGM ("<u>Company Stock Options</u>," and each a "<u>Company Stock</u> <u>Option</u>") and, as of immediately prior to the Offer Closing Time, the vesting for each restricted stock units granted by IGM ("<u>Company Restricted Stock Units</u>," and each a "<u>Company Restricted Stock Unit</u>"), shall be accelerated and: (i) (A) each Company Stock Option that has an exercise price per share that is less than the Cash Amount (each, an "<u>In-the-Money Option</u>") that is then outstanding will be cancelled and, in exchange therefor, the holder of such cancelled In-the-Money Option will be entitled to receive in consideration of the cancellation of such In-the-Money Option (1) an amount in cash without interest, less any applicable tax withholding, equal to the product obtained by multiplying (x) the excess of the Cash Amount over the exercise price per share of Shares underlying such In-the-Money Option by (y) the number of Shares underlying such In-the-Money Option as of immediately prior to the Effective Time, and (2) one CVR for each Share underlying such In-the-Money Option, and (B) each Company Stock Option that has an exercise price per share that is equal

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to or greater than the Cash Amount that is then outstanding will be cancelled for no consideration; and (ii) each Company Restricted Stock Unit that is then outstanding will be cancelled and, in exchange therefor, the holder of such cancelled Company Restricted Stock Unit will be entitled to receive in consideration of the cancellation of such Company Restricted Stock Unit (A) an amount in cash without interest, less any applicable tax withholding, equal to the Cash Amount, and (B) one CVR.

Prior to the Effective Time, IGM shall satisfy all of its notification requirements under the terms of each outstanding and unexercised Company Pre-Funded Warrant, and, at the Effective Time, each Company Pre-Funded Warrant shall be canceled and holders of such warrants will be entitled to receive: (1) an amount in cash without interest, less any applicable tax withholding, equal to the product obtained by multiplying (x) the excess of the Cash Amount over the exercise price per share of such Company Pre-Funded Warrant by (y) the number of Shares underlying such Company Pre-Funded Warrant as of immediately prior to the Effective Time; and (2) one CVR for each Share underlying such Company Pre-Funded Warrant.

The Merger Agreement is more fully described in "<u>The Tender Offer—Section 7. Summary of the Merger</u> <u>Agreement and Certain Other Agreements</u>," which also contains a discussion of the treatment of Company Restricted Stock Units and Company Stock Options in the Merger. "<u>Special Factors—Section 6. Material</u> <u>U.S. Federal Income Tax Consequences of the Offer and the Merger</u>" below describes the material U.S. federal income tax consequences generally applicable to Holders (as defined below) whose Shares are tendered and accepted for purchase pursuant to the Offer or whose Shares are exchanged in the Merger.

Because the Merger will be consummated in accordance with Section 251(h) of the DGCL, approval of the Merger will not require a vote of IGM stockholders. Section 251(h) of the DGCL provides that stockholder approval of a merger is not required if certain requirements are met, including that: (i) the acquiring company consummates a tender offer for any and all of the outstanding stock of IGM that, absent Section 251(h) of the DGCL, would be entitled to vote on the merger; (ii) following the consummation of such tender offer, the stock irrevocably accepted for purchase pursuant to such offer and received by the depositary prior to expiration of such offer, together with the stock otherwise owned by the consummating corporation or its affiliates and any "rollover stock" (as defined in Section 251(h) of the DGCL), equals at least such percentage of the stock of IGM to be acquired that, absent Section 251(h) of the DGCL, would be required to adopt the Merger Agreement; and (iii) each outstanding share (other than "excluded stock" (as defined in Section 251(h) of the DGCL)) of the company that is subject of and not irrevocably accepted for purchase in such offer is converted in such merger into the right to receive the same amount and kind of cash, property, rights or securities paid for such shares pursuant to such offer. If the Minimum Tender Condition is satisfied and we accept Shares for payment pursuant to the Offer, we will hold a sufficient number of Shares to ensure that IGM will not be required to submit the adoption of the Merger Agreement to a vote of its stockholders. As a result of the Merger, IGM will cease to be a publicly traded company and will become a wholly owned subsidiary of Parent. See "<u>Special</u> <u>Factors—Section 2. Purpose of the Offer and Plans for IGM</u>."

**The Merger Agreement, the CVR Agreement, the Limited Guaranty, this Offer to Purchase and the related Letter of Transmittal contain important information and should be read carefully and in their entirety before any decision is made with respect to the Offer.** 

#### SPECIAL FACTORS
1. **BACKGROUND OF THE OFFER; CONTACTS WITH IGM.** 

**Background of the Offer and the Merger; Past Contacts or Negotiations between Parent, Merger Sub and IGM. The following is a description of contacts between representatives of Parent and Merger Sub with representatives of IGM that resulted in the execution of the Merger Agreement and the agreements related to the Offer. For a review of IGM's activities relating to these contacts, please refer to IGM's Schedule 14D-9 being mailed to stockholders with this Offer to Purchase.** 

#### Background of the Offer and the Merger.
On May 21, 2025, a representative of IGM senior management first contacted a representative of Parent and TCM to discuss a potential transaction with IGM.

On May 23, 2025, representatives of IGM senior management spoke with representatives of Parent and TCM to provide certain background information regarding IGM and to invite Parent to participate in IGM's process for a potential transaction with IGM.

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#### **TABLE OF CONTENTS**
On May 28, 2025, IGM and Parent entered into a confidentiality agreement, which included a 1-year standstill provision and customary fall-away provisions.

Later on May 28, 2025, IGM provided certain representatives of Parent and TCM with access to IGM's electronic data room. Subsequently, Parent and TCM conducted due diligence review of non-public information provided in IGM's electronic data room.

On May 30, 2025, IGM senior management contacted representatives of Parent and invited Parent to submit a proposal for a potential transaction by June 10, 2025.

On June 5, 2025, representatives of Parent and TCM spoke with IGM senior management to discuss certain due diligence topics, including certain of IGM's clinical programs and financial information of IGM. Parent and TCM continued to conduct due diligence review of non-public information provided by IGM.

On June 6, 2025, Parent submitted a non-binding proposal (the "<u>Original Proposal</u>") to acquire 100% of the equity of IGM for $1.204 per share in cash plus a contingent value right ("<u>CVR</u>") for each share representing the right to receive: (a) 80% of the net proceeds payable from any license or disposition of IGM's product candidates, imvotamab, IGM-2644 and aplitabart, within 12 months of the close; and (b) 100% of the final Closing Net Cash in excess of $82.0 million, as determined within 30 days following the close. Parent's proposal included a $6.5 million retention and was based on the availability of at least $82.0 million of closing net cash.

On June 10, 2025, IGM senior management contacted representatives of Parent to clarify IGM's understanding of the Original Proposal.

On June 11, 2025, IGM senior management contacted representatives of Parent requesting that Parent submit a revised proposal for a potential transaction by June 13, 2025.

On June 13, 2025, Parent submitted a revised non-binding proposal (the "<u>Revised Proposal</u>") to acquire 100% of the equity of IGM for $1.228 per share in cash plus a CVR for each share representing the right to receive: (a) 80% of the net proceeds payable from any license or disposition of IGM's product candidates and/or intellectual property within 12 months of the close; and (b) 100% of the final Closing Net Cash in excess of $82.0 million, as determined within 30 days following the close. Parent's proposal included a $5.0 million retention and was based on the availability of at least $82.0 million of closing net cash and approximately 62.7 million fully diluted shares outstanding calculated using the treasury stock method.

On June 15, 2025, IGM senior management contacted representatives of Parent to provide feedback from IGM's Board of the Revised Proposal.

On June 17, 2025, IGM senior management contacted representatives of Parent requesting that Parent submit a revised proposal for a potential transaction by June 18, 2025.

On June 18, 2025, Parent submitted a revised non-binding proposal (the "<u>Second Revised Proposal</u>") to acquire 100% of the equity of IGM for $1.246 per share in cash plus a CVR for each share representing the right to receive: (a) 80% of the net proceeds payable from any license or disposition of IGM's product candidates and/or intellectual property within 12 months of the close; and (b) 100% of the final Closing Net Cash in excess of $82.0 million, as determined 5 business days prior to the close. Parent's proposal included a $4.0 million retention and was based on the availability of at least $82.0 million of closing net cash and approximately 62.6 million fully diluted shares outstanding calculated using the treasury stock method.

On June 19, 2025, IGM senior management, at the direction of the IGM Board, notified Parent of IGM's intent to enter into a definitive agreement.

On June 23, 2025, representatives of Parent and TCM spoke with IGM senior management to discuss certain financial- and clinical program-related due diligence topics.

On June 24, 2025, representatives from Parent and TCM provided IGM senior management and representatives of Wilson Sonsini Goodrich & Rosati, P.C. ("<u>WSGR</u>"), counsel to IGM, with initial drafts of the Merger Agreement, the CVR Agreement, the Limited Guaranty and drafts of the exhibits and schedules to be included in the Merger Agreement, including the Form of Tender and Support Agreement. The initial drafts: (a) reflected the terms of the Second Revised Proposal, except that the upfront cash amount per share was increased slightly to $1.248 per share based on an updated calculation of the fully diluted shares outstanding calculated using the treasury stock method provided to Parent by IGM; and (b) generally included customary

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terms and conditions for such an agreement including, among other things, for: (i) the transaction to be structured as a cash tender offer followed immediately by a back-end merger pursuant to DGCL Section 251(h); (ii) the acceleration and cash out of certain IGM equity awards; (iii) customary exceptions to the definition of "Company Material Adverse Effect," which generally defines the standard for certain closing risk; (iv) customary representations and warranties with respect to IGM and Parent and Merger Sub, including a representation by Parent and Merger Sub regarding the concurrent delivery of an executed limited guaranty to guarantee Parent and Merger Sub's obligations under the Merger Agreement and the CVR Agreement; (v) IGM's ability to provide due diligence to, and negotiate a merger agreement with, a party making an unsolicited acquisition proposal that constitutes or would reasonably be expected to lead to a superior proposal; and (vi) IGM's ability to terminate the Merger Agreement to accept a superior proposal after providing Parent with a right to match such proposal. The Merger Agreement also included, among other things, the definition of closing net cash, which included adjustments to account for indebtedness of IGM and its subsidiaries as of closing, transaction expenses and estimated costs post-merger closing (including a cap for any legal proceedings and settlements).

On June 27, 2025, WSGR provided representatives from Parent, TCM and Gibson, Dunn & Crutcher LLP ("<u>Gibson</u>"), counsel to Parent, with a revised draft of the Merger Agreement, which reflected certain revisions, including: (i) a lesser termination fee payable by IGM; and (iii) raising the cap on the annual premium for the D&O insurance tail policy to be obtained.

Later on June 27, 2025, representatives from Parent and TCM provided IGM senior management and representatives of WSGR with a revised draft of the Merger Agreement, which reflected certain revisions, including: (i) a $2.425 million termination fee payable by IGM; and (iii) lowering the cap on the annual premium for the D&O insurance tail policy to be obtained.

On June 28, 2025, WSGR provided representatives from Parent, TCM and Gibson, Dunn & Crutcher LLP ("<u>Gibson</u>"), counsel to Parent, with a revised draft of the Merger Agreement and CVR Agreement, which reflected certain revisions, including: (i) a slightly lower upfront cash amount per share of $1.247 based on an updated calculation of the fully diluted shares outstanding calculated using the treasury stock method provided to Parent by IGM; and (ii) clarifying the definition of the CVR Products to include IGM's product candidates known as IGM-8447 and IGM-2537 in addition to IGM's product candidates known as imvotamab, IGM-2644, aplitabart (or IGM-8444) and IGM-7354.

From June 29, 2025 to June 30, 2025, representatives of Parent, Merger Sub and Gibson, on the one hand, and representatives of the IGM senior management team and WSGR, on the other hand, exchanged drafts of the Merger Agreement and CVR Agreement to reflect certain minor revisions, including the removal of the Form of Tender and Support Agreement.

On July 1, 2025, the Merger Agreement was signed by Parent, Merger Sub and IGM, and the Limited Guaranty was signed by TCP, Parent, Merger Sub and IGM.

On July 16, 2025, Parent commenced the Offer pursuant to the Merger Agreement, and later on July 16, 2025, IGM filed a Schedule 14D-9.

2. **PURPOSE OF THE OFFER AND PLANS FOR IGM.** 

**Purpose of the Offer. The purpose of the Offer and the Merger is for Parent to acquire control of, and the entire equity interest in, IGM. Pursuant to the Merger, Parent will acquire all of the stock of IGM not purchased pursuant to the Offer or otherwise.** 

Stockholders of IGM who sell their Shares in the Offer will cease to have any equity interest in IGM or any right to participate in its earnings and future growth.

**Merger Without a Stockholder Vote. If the Offer is consummated, we do not anticipate seeking the approval of IGM's remaining public stockholders before effecting the Merger. Section 251(h) of the DGCL provides that following consummation of a successful tender offer for a public corporation, and subject to certain statutory provisions, if the acquiring corporation owns at least the amount of shares of each class of stock of the target corporation that would otherwise be required to adopt a merger agreement for the target corporation, and the other stockholders receive the same consideration for their stock in the merger as was payable in the tender offer, the acquiring corporation can effect a merger without the action of the other stockholders of the target** 

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corporation. Accordingly, if we consummate the Offer, we intend to effect the closing of the Merger without a vote of the stockholders of IGM in accordance with Section 251(h) of the DGCL, upon the terms and subject to the satisfaction or waiver of the conditions to the Merger, as soon as practicable after the consummation of the Offer. Accordingly, we do not expect there to be a significant period of time between the consummation of the Offer and the consummation of the Merger.

**Plans for IGM. At the Effective Time, the certificate of incorporation and bylaws of IGM will each be amended and restated in their entirety pursuant to the terms of the Merger Agreement. Merger Sub's directors immediately prior to the Effective Time will be the initial directors of the Surviving Corporation, and the officers of the Surviving Corporation shall be the respective individuals who served as the officers of Merger Sub as of immediately prior to the Effective Time, in each case, until their respective successors are duly elected and qualified, or their earlier death, resignation or removal. Each director and officer of IGM immediately prior to the Effective Time shall execute and deliver a letter effectuating his or her resignation as a member of the IGM Board or as an officer of IGM. The Surviving Corporation will not have any employees, but may engage former employees of IGM as consultants. No such terms have been agreed upon. See "<u>The Tender Offer—Section 7.</u> <u>Summary of the Merger Agreement and Certain Other Agreements—Governance of the Surviving Corporation</u>."** 

At the Effective Time, Merger Sub will be merged with and into IGM, the separate existence of Merger Sub will cease, and IGM will continue as the Surviving Corporation in the Merger. IGM's Shares will be delisted and will no longer be quoted on Nasdaq, and IGM's obligation to file periodic reports under the Exchange Act will be suspended, and IGM will be privately held.

Except as disclosed in this Offer to Purchase, Parent and Merger Sub do not have any present plan or proposal that would result in the acquisition by any person of additional securities of IGM, the disposition of securities of IGM, an extraordinary corporate transaction, such as a merger, reorganization or liquidation, involving IGM or any of its subsidiaries or the purchase, sale or transfer of a material amount of assets of IGM or any of its subsidiaries.

3. **REPORTS, OPINIONS, APPRAISALS AND NEGOTIATIONS.** 

Based on the determination of the IGM Board, IGM retained Houlihan Lokey Capital, Inc. ("<u>Houlihan</u> <u>Lokey</u>") as its financial advisor in connection with the Offer, the Merger and the Transactions. In connection with this engagement, the IGM Board requested that Houlihan Lokey provide an opinion to the IGM Board as to the fairness, from a financial point of view, to the holders of Shares (other than Parent, Merger Sub and their respective affiliates) of the Offer Price proposed to be paid to such holders pursuant to the terms of the Merger Agreement. On July 1, 2025, Houlihan Lokey orally rendered to the IGM Board its opinion, which was subsequently confirmed by the delivery of a written opinion dated July 1, 2025. See "<u>Special Factors—The</u> <u>Solicitation or Recommendation–Opinion of Houlihan Lokey Capital, Inc.</u>" and Annex I of the Schedule 14D-9, which information is hereby incorporated by reference.

None of Parent, Merger Sub or the other TCP representatives engaged a financial advisor in connection with the Offer or the Merger.

4. **PRICE RANGE OF SHARES; DIVIDENDS.** 

According to IGM's Annual Report on Form 10-K for the year ended December 31, 2024 filed with the SEC on March 6, 2025 and as amended on April 30, 2025, the Shares are traded on Nasdaq under the symbol "<u>IGMS</u>." IGM has advised Parent that, as of the close of business on June 27, 2025, there were: (i) 60,189,151 Shares issued and outstanding (34,802,168 shares of voting common stock and 25,386,983 shares of non-voting common stock); (ii) no Shares held by IGM in its treasury; (iii) 4,308,913 Shares subject to outstanding Company Stock Options with a weighted-average exercise price of approximately $16.27 per share, 96,328 of which were In-the-Money Options with a weighted-average exercise price of approximately $1.00 per share; (iv) 1,030,014 Shares subject to outstanding Company Restricted Stock Units; and (v) 1,334,332 Shares subject to Company Pre-Funded Warrants, with an exercise price of $0.01 per Share. The following table sets forth, for the quarters indicated, the high and low sales prices per Share on Nasdaq with respect to the years ended December 31, 2024 and 2023 and the current year.

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| | | |
|:---|:---|:---|
| **Current Year** | **High** | **Low**  |
| First Quarter | $7.09 | $1.12  |
| Second Quarter | &nbsp;&nbsp;1.47 | &nbsp;&nbsp;0.92  |
| Third Quarter (through July 15, 2025) | &nbsp;&nbsp;1.39 | &nbsp;&nbsp;1.29 |

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| | | |
|:---|:---|:---|
| **Year Ended December 31, 2024** | **High** | **Low**  |
| First Quarter | $17.70 | $8.14  |
| Second Quarter | &nbsp;&nbsp;12.31 | &nbsp;&nbsp;6.39  |
| Third Quarter | &nbsp;&nbsp;22.50 | &nbsp;&nbsp;6.17  |
| Fourth Quarter | &nbsp;&nbsp;20.35 | &nbsp;&nbsp;5.79 |

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| | | |
|:---|:---|:---|
| **Year Ended December 31, 2023** | **High** | **Low**  |
| First Quarter | $27.92 | $13.64  |
| Second Quarter | &nbsp;&nbsp;14.82 | &nbsp;&nbsp;&nbsp;8.51  |
| Third Quarter | &nbsp;&nbsp;10.96 | &nbsp;&nbsp;&nbsp;6.45  |
| Fourth Quarter | &nbsp;&nbsp;&nbsp;9.49 | &nbsp;&nbsp;&nbsp;3.81 |

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On July 15, 2025, the last full trading day prior to the date of this Offer to Purchase, the reported closing sales price per Share on Nasdaq during normal trading hours was $1.35 per Share.

IGM has never paid cash dividends on its Shares. Additionally, under the terms of the Merger Agreement, IGM is not permitted to declare or pay any dividends on or make other distributions in respect of any of its capital stock. See "<u>The Tender Offer—Section 10. Dividends and Distributions</u>." Stockholders are urged to obtain a current market quotation for the Shares.

5. **POSSIBLE EFFECTS OF THE OFFER ON THE MARKET FOR THE SHARES; NASDAQ LISTING; EXCHANGE ACT REGISTRATION AND MARGIN REGULATIONS.** 

**Possible Effects of the Offer on the Market for the Shares. The purchase of Shares pursuant to the Offer will reduce the number of Shares that might otherwise trade publicly and could adversely affect the liquidity and market value of the remaining Shares held by the public. The purchase of Shares pursuant to the Offer can also be expected to reduce the number of holders of Shares. We cannot predict whether the reduction in the number of Shares that might otherwise trade publicly would have an adverse or beneficial effect on the market price or marketability of the Shares or whether it would cause future market prices to be greater or less than the Offer Price.** 

**Nasdaq Listing. Depending on the number of Shares purchased pursuant to the Offer, the Shares may no longer meet the requirements for continued listing on Nasdaq. According to the published guidelines of The Nasdaq Stock Market, LLC, Nasdaq would consider disqualifying the Shares for listing on Nasdaq if, among other possible grounds: (i) the total number of holders of record and holders of beneficial interest, taken together, in the Shares falls below 400; (ii) the bid price for a Share over a 30 consecutive business day period is less than $1.00; or (iii) (A) IGM has stockholders' equity of less than $10 million, the number of publicly held Shares falls below 750,000, the market value of publicly held Shares over a 30 consecutive business day period is less than $5 million or there are fewer than two active and registered market makers in the Shares over a ten consecutive business day period; (B) the number of publicly held Shares falls below 1,100,000, the market value of publicly held Shares over a 30 consecutive business day period is less than $15 million, there are fewer than four active and registered market makers in the Shares over a ten consecutive business day period, or the market value of IGM's listed securities is less than $50 million over a 30 consecutive business day period; or (C) the number of publicly held shares falls below 1,100,000, the market value of publicly held Shares over a 30 consecutive business day period is less than $15 million, there are fewer than four active and registered market makers in the Shares over a ten consecutive business day period, or IGM's total assets and total revenue is less than $50 million each for the most recently completed fiscal year (or in two of the last three fiscal years). Nasdaq has instituted temporary waivers of certain listing rules, but there can be no guarantee as to if or when these rules will be reinstated.** 

On June 6, 2025, IGM received a letter from the Listing Qualifications Staff (the "<u>Staff</u>") of The Nasdaq Stock Market LLC indicating that IGM was no longer in compliance with the minimum Market Value of Listed Securities ("<u>MVLS</u>") of $50,000,000 required for continued listing on The Nasdaq Global Select Market pursuant to Nasdaq Listing Rule 5450(b)(2)(A). The letter also indicated that IGM will be provided with a compliance period of 180 calendar days, or until December 3, 2025, in which to regain compliance pursuant to Nasdaq Listing Rule 5450(b)(2)(A). To regain compliance with such minimum price requirement, IGM's MVLS must close at $50,000,000 or more for a minimum of 10 consecutive business days prior to December 3, 2025. IGM's Shares continue to trade on Nasdaq under the symbol "IGMS."

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Shares held by officers or directors of IGM, or by any beneficial owner of more than 10% of the Shares, will not be considered as being publicly held for this purpose. According to IGM, as of the close of business on June 27, 2025, there were: (i) 60,189,151 Shares issued and outstanding (34,802,168 shares of voting common stock and 25,386,983 shares of non-voting common stock); (ii) no Shares held by IGM in its treasury; (iii) 4,308,913 Shares subject to outstanding Company Stock Options with a weighted-average exercise price of approximately $16.27 per share, 96,328 of which were In-the-Money Options with a weighted-average exercise price of approximately $1,00 per share; (iv) 1,030,014 Shares subject to outstanding Company Restricted Stock Units; and (v) 1,334,332 Shares subject to Company Pre-Funded Warrants, with an exercise price of $0.01 per Share. If, as a result of the purchase of Shares pursuant to the Offer or otherwise, the Shares are delisted from Nasdaq, the market for Shares will be adversely affected.

If Nasdaq were to delist the Shares, it is possible that the Shares would continue to trade on other securities exchanges or in the over-the-counter market and that price or other quotations for the Shares would be reported by other sources. The extent of the public market for such Shares and the availability of such quotations would depend, however, upon such factors as the number of stockholders and the aggregate market value of such securities remaining at such time, the interest in maintaining a market in the Shares on the part of securities firms, the possible termination of registration under the Exchange Act as described below, and other factors. We cannot predict whether the reduction in the number of Shares that might otherwise trade publicly would have an adverse or beneficial effect on the market price for or marketability of the Shares or whether it would cause future market prices to be greater or less than the Offer Price.

#### Trading in the Shares will cease upon consummation of the Merger if trading has not ceased earlier as discussed above.
**Exchange Act Registration. The Shares currently are registered under the Exchange Act. The purchase of the Shares pursuant to the Offer may result in the Shares becoming eligible for deregistration under the Exchange Act. Registration of the Shares may be suspended by IGM upon application to the SEC if the outstanding Shares are not listed on a "national securities exchange" and if there are fewer than 300 holders of record of Shares.** 

We intend to seek to cause IGM to apply for suspension of registration of the Shares as soon as possible after consummation of the Offer if the requirements for suspension of registration are met. Suspension of registration of the Shares under the Exchange Act would reduce the information required to be furnished by IGM to its stockholders and to the SEC and would make certain provisions of the Exchange Act (such as the short-swing profit recovery provisions of Section 16(b), the requirement of furnishing a proxy statement or information statement in connection with stockholders' meetings or actions in lieu of a stockholders' meeting pursuant to Sections 14(a) and 14(c) under the Exchange Act and the related requirement of furnishing an Annual Report to stockholders) no longer applicable with respect to the Shares. In addition, if the Shares are no longer registered under the Exchange Act, the requirements of Rule 13e-3 under the Exchange Act with respect to "going private" transactions would no longer be applicable to IGM. Furthermore, the ability of "affiliates" of IGM and persons holding "restricted securities" of IGM to dispose of such securities pursuant to Rule 144 under the Securities Act of 1933, as amended, may be impaired or eliminated. If registration of the Shares under the Exchange Act were suspended, the Shares would no longer be eligible for continued inclusion on the Board of Governors of the Federal Reserve System's (the "<u>Federal Reserve Board</u>") list of "margin securities" or eligible for stock exchange listing.

If registration of the Shares is not suspended prior to the Merger, then the registration of the Shares under the Exchange Act will be suspended following completion of the Merger.

**Margin Regulations. The Shares are currently "margin securities" under the regulations of the Federal Reserve Board, which has the effect, among other things, of allowing brokers to extend credit using such Shares as collateral. Depending upon factors similar to those described above regarding listing and market quotations, following the Offer, the Shares may no longer constitute "margin securities" for the purposes of the margin regulations of the Federal Reserve Board, in which event the Shares would be ineligible as collateral for margin loans made by brokers.** 

6. **MATERIAL U.S. FEDERAL INCOME TAX CONSEQUENCES OF THE OFFER AND THE MERGER.** 

The following summary describes the material U.S. federal income tax consequences generally applicable to Holders (as defined below) whose Shares are exchanged for cash and CVRs in the Offer or Merger. This

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#### **TABLE OF CONTENTS**
summary is for general information purposes only and is not tax advice. This summary is based on the Internal Revenue Code of 1986, as amended (the "<u>Code</u>"), U.S. Treasury regulations promulgated under the Code ("<u>Treasury Regulations</u>"), published rulings, administrative pronouncements and judicial decisions, all as in effect as of the date hereof and all of which are subject to change or differing interpretations, possibly with retroactive effect. Any such change could affect the continuing validity of this summary. This summary addresses only Holders who hold their Shares as capital assets within the meaning of Section 1221 of the Code (generally, property held for investment) and does not address all of the tax consequences that may be relevant to Holders in light of their particular circumstances or to certain types of Holders subject to special treatment under the Code, including pass-through entities (including partnerships and S corporations for U.S. federal income tax purposes) and partners or investors who hold their Shares through such entities, certain financial institutions, brokers, dealers or traders in securities or other persons that generally mark their securities to market for U.S. federal income tax purposes, insurance companies, expatriates, mutual funds, real estate investment trusts, regulated investment companies, cooperatives, tax-exempt organizations (including private foundations), retirement plans, controlled foreign corporations, passive foreign investment companies or and investors therein, persons who are subject to the alternative minimum tax, persons who hold their Shares as part of a straddle, hedge, conversion, constructive sale, synthetic security, integrated investment, or other risk-reduction transaction for U.S. federal income tax purposes, persons that have a functional currency other than the U.S. dollar, persons that own or have owned within the past five years (or are deemed to own or to have owned within the past five years) 5% or more of the outstanding Shares, Holders that exercise appraisal rights, Holders whose Shares are "qualified small business stock" within the meaning of Section 1202 of the Code or Shares to which the rollover provisions of Section 1045 of the Code apply, and persons who acquired their Shares upon the vesting and cancellation of Company Stock Options or Company Restricted Stock Units in connection with the Merger or otherwise as compensation. This summary does not address any U.S. federal estate, gift, or other non-income tax consequences, the effects of the Medicare contribution tax on net investment income, or any state, local, or non-U.S. tax consequences.

As used in this summary, the term "<u>U.S. Holder</u>" means a beneficial owner of Shares that, for U.S. federal income tax purposes, is: (i) an individual who is a citizen or resident of the United States; (ii) a corporation, or other entity classified as a corporation for U.S. federal income tax purposes, that is created or organized in or under the laws of the United States or any state thereof or the District of Columbia; (iii) an estate, the income of which is subject to U.S. federal income taxation regardless of its source; or (iv) a trust if (A) a court within the United States is able to exercise primary supervision over the administration of the trust and one or more "U.S. persons" (within the meaning of Section 7701(a)(30) of the Code) has the authority to control all substantial decisions of the trust or (B) the trust has a valid election in effect under applicable Treasury Regulations to be treated as a U.S. person.

As used in this summary, the term "<u>Non-U.S. Holder</u>" means a beneficial owner of Shares that is neither a U.S. Holder nor a partnership for U.S. federal income tax purposes, and the term "Holder" or "Holders" means a U.S. Holder or a Non-U.S. Holder.

If a partnership (including any entity or arrangement classified as a partnership for U.S. federal income tax purposes) exchanges Shares for cash and CVRs pursuant to the Offer or the Merger, the tax treatment of a partner in the partnership generally will depend upon the status of the partner, the activities of the partnership, and certain determinations made at the partner level. The partnership and partners of the partnership holding Shares should consult their tax advisors regarding the particular tax consequences of exchanging Shares for cash and CVRs pursuant to the Offer or the Merger applicable to them.

We have not sought, and do not expect to seek, a ruling from the IRS as to any U.S. federal income tax consequence described herein, and no assurance can be given that the IRS will not take a position contrary to the discussion below, or that a court will not sustain any challenge by the IRS in the event of litigation.

**Holders are urged to consult their tax advisors to determine the tax consequences to them of exchanging Shares for cash and CVRs pursuant to the Offer or the Merger in light of their particular circumstances.** 

**Tax Considerations for U.S. Holders. The exchange of Shares for cash and CVRs pursuant to the Offer or the Merger will be a taxable transaction for U.S. federal income tax purposes. The amount of gain or loss a U.S. Holder recognizes, and the timing and character of a portion of such gain or loss, depends on the** 

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U.S. federal income tax treatment of the CVRs, with respect to which there is a significant amount of uncertainty. The installment method of reporting any gain attributable to the receipt of a CVR generally will not be available with respect to the disposition of Shares pursuant to the Offer or the Merger because the Shares are traded on an established securities market.

There is no legal authority directly addressing the U.S. federal income tax treatment of the receipt of the CVRs or payments received thereunder in connection with the Offer or the Merger. The receipt of the CVRs as part of the Offer or the Merger consideration might be treated as a "closed transaction" or as an "open transaction" for U.S. federal income tax purposes, or in some other manner, and such questions are inherently factual in nature. Accordingly, Holders are urged to consult with their tax advisors regarding this issue.

Pursuant to Treasury Regulations addressing contingent payment obligations analogous to the CVRs, if the fair market value of the CVR is "reasonably ascertainable," a U.S. Holder should treat the transaction as a "closed transaction" and treat the fair market value of the CVRs as part of the consideration received in the Offer or the Merger for purposes of determining gain or loss. On the other hand, if the fair market value of the CVRs cannot be reasonably ascertained, a U.S. Holder may treat the transaction as an open transaction for purposes of determining gain or loss. These Treasury Regulations state that only in "rare and extraordinary" cases would the value of contingent payment obligations not be reasonably ascertainable. As noted above, there is no authority directly addressing whether contingent payment rights with characteristics similar to the rights under a CVR should be treated as "open transactions" or "closed transactions," and such question is inherently factual in nature. The CVRs also may be treated as contract rights, debt instruments or deferred payment contract rights for U.S. federal income tax purposes, which would affect the amount, timing, and character of any gain, income or loss with respect to the CVRs. We urge you to consult your own tax advisor with respect to the proper characterization of the receipt of, and payments made with respect to, a CVR.

As a result, we cannot express a definitive conclusion as to the U.S. federal income tax treatment of receipt of the CVRs or receipt of any payment pursuant to the CVRs. However, we intend to treat the receipt of the CVRs as a closed transaction and payments received pursuant to the CVRs as amounts realized on the disposition (or partial disposition) of the CVRs. We cannot give any assurance that the IRS would not assert, or that a court would not sustain, a position contrary to this treatment. In such event, the tax consequences of the receipt of CVRs and/or payments with respect to the CVRs could differ materially from those summarized below (including, potentially, a portion or all of payments made with respect to the CVRs giving rise to ordinary income, rather than capital gain).

No opinion of counsel or ruling has been or will be sought from the IRS regarding the tax treatment of the CVRs and payments received pursuant to the CVRs. We cannot give any assurance that the IRS would not assert, or that a court would not sustain, a position contrary to this treatment. In such event, the tax consequences of the receipt of CVRs and/or payments with respect to the CVRs could differ materially from those summarized below (including, potentially, a portion or all of payments made with respect to the CVRs giving rise to ordinary income, rather than capital gain). No opinion of counsel or ruling has been or will be sought from the IRS regarding the tax treatment of the CVRs.

**Treatment as a Closed Transaction. If the receipt of a CVR is part of a closed transaction, a U.S. Holder generally would recognize capital gain or loss on a sale of Shares for the Offer Price pursuant to the Offer or an exchange of Shares for the Offer Price pursuant to the Merger, in an amount equal to the difference, if any, between: (i) the sum of the Cash Amount received plus the fair market value (determined as of the closing of the Offer or the Effective Time, as the case may be) of any CVRs received; and (ii) the U.S. Holder's adjusted tax basis in the Shares sold or exchanged. Gain or loss generally would be calculated separately for each block of Shares (that is, Shares acquired at the same cost in a single transaction) tendered pursuant to the Offer or exchanged for the Offer Price pursuant to the Merger. The proper method to determine the fair market value of a CVR is not clear, but it is possible that the trading value of IGM's common stock would be considered along with other factors in making that determination. Any capital gain or loss recognized will be long-term capital gain or loss if the U.S. Holder's holding period for such Shares exceeds one year. The deductibility of capital losses is subject to limitations.** 

A U.S. Holder's initial tax basis in a CVR received in either the Offer or the Merger would equal the fair market value of such CVR (determined as of the closing of the Offer or the Effective Time, as the case may be) as determined for U.S. federal income tax purposes. The holding period for a CVR would begin on the day

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following the date of the closing of the Offer or the Effective Time, as the case may be. We intend to cooperate with the Paying Agent to send to each U.S. Holder an IRS Form 1099-B reflecting our determination of the fair market value of the CVRs issued in the Offer or Merger. Such determination is not binding on the IRS as to the stockholder's tax treatment or the fair market value of the CVRs, and each Holder should be aware that the IRS may challenge the fair market value of the CVRs reported by such Holder.

As noted above, there is no authority directly addressing the U.S. federal income tax treatment of contingent payment rights with characteristics similar to the rights under the CVRs, and, therefore, the amount, timing and character of any gain, income or loss with respect to the CVRs is uncertain. For example, payments with respect to the CVRs could be treated as payments with respect to a sale or exchange of a capital asset or as giving rise to ordinary income. It is also possible that, were a payment to be treated as being with respect to the sale of a capital asset, a portion of such payment would constitute imputed interest, as described below. We intend to treat any payment received by a U.S. Holder in respect of such CVRs (except to the extent any portion of such payment is required to be treated as imputed interest, as described below) as an amount realized on the disposition of the CVR by the U.S. Holder. Assuming that this method of reporting is correct, a U.S. Holder should recognize gain or loss equal to the difference between such payment (less any portion of such payment required to be treated as imputed interest, as described below) and the U.S. Holder's adjusted tax basis in the CVR. The gain or loss should be long-term capital gain or loss if the U.S. Holder has held the CVR for more than one year at the time of such payment. Additionally, a U.S. Holder may recognize capital loss to the extent of any remaining basis after the expiration of any right to cash payments under such U.S. Holder's CVR. The deductibility of capital losses is subject to limitations.

**Treatment as an Open Transaction. If the receipt of a CVR pursuant to the Offer or the Merger is treated under the open transaction method of accounting for U.S. federal income tax purposes, the fair market value of the CVR will not be treated as additional consideration for the Shares at the time the CVR is received, and the U.S. Holder will not have any tax basis in the CVR. Instead, the U.S. Holder will take payments pursuant to the CVRs into account when made or deemed made in accordance with the U.S. Holder's regular method of accounting for U.S. federal income tax purposes. Generally, a portion of such payments will be treated as imputed interest, as described in more detail below, and the balance as additional consideration recognized in exchange for the Shares.** 

If the receipt of a CVR is part of an open transaction then, although not entirely clear, the sum of the Cash Amount received for a U.S. Holder's Shares and the portion of the payments pursuant to the CVR that is not treated as imputed interest will generally be applied first against a U.S. Holder's adjusted tax basis in the Shares and any excess treated as gain. A U.S. Holder will recognize capital loss with respect to a Share to the extent that the holder's adjusted tax basis in such Share exceeds the sum of the Cash Amount received for a U.S. Holder's Shares and the cash received pursuant to the CVR that is not treated as imputed interest, although it is possible that such U.S. Holder may not be able to recognize such loss until the resolution of all contingencies under the CVRs or possibly until such U.S. Holder's abandonment of the U.S. Holder's CVR. Any such capital gain or loss will be long-term capital gain or loss if the U.S. Holder's holding period in the Share exceeds one year. The deductibility of capital losses is subject to limitations. Gain or loss generally will be determined separately for each block of Shares (that is, Shares of the same class acquired at the same cost on the same day) exchanged pursuant to the Offer or the Merger.

**Imputed Interest. A portion of any payments pursuant to the CVRs that are made more than six months after the closing of the Offer or the Effective Time, as the case may be, may be treated as imputed interest, which would be ordinary income to the U.S. Holder of a CVR. The portion of any payment made with respect to a CVR treated as imputed interest under Section 483 of the Code will be determined at the time such payment is made and generally should equal the excess of: (i) the amount of the payment in respect of the CVRs; over (ii) the present value of such amount as of the closing of the Offer or the Effective Time, as the case may be, calculated using the applicable federal rate as the discount rate. The applicable federal rate is published monthly by the IRS. A U.S. Holder must include in its taxable income interest imputed pursuant to Section 483 of the Code (if any) using such Holder's regular method of accounting for U.S. federal income tax purposes.** 

U.S. Holders are urged to consult their tax advisors with respect to the proper characterization of the CVRs and the tax considerations thereof (including any future payments made under the CVRs).

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**Tax Considerations for Non-U.S. Holders. Any gain realized by a Non-U.S. Holder upon the tender of Shares pursuant to the Offer or the exchange of Shares pursuant to the Merger, as the case may be, generally will not be subject to U.S. federal income tax unless:** 

&nbsp;&nbsp;&nbsp;&nbsp;• the gain is effectively connected with a U.S. trade or business of such Non-U.S. Holder (and, if an applicable income tax treaty so provides, is also attributable to a permanent establishment maintained by such Non-U.S. Holder in the United States), in which case the Non-U.S. Holder generally will be taxed in the same manner as a U.S. Holder (as described above under "U.S. Holders"), except that if the Non-U.S. Holder is a foreign corporation, an additional branch profits tax may apply at a rate of 30% (or a lower applicable treaty rate);

&nbsp;&nbsp;&nbsp;&nbsp;• the Non-U.S. Holder is a nonresident alien individual who is present in the U.S. for 183 days or more in the taxable year of the closing of the Offer or the Effective Time, as the case may be, and certain other conditions are met, in which case the Non-U.S. Holder may be subject to a 30% U.S. federal income tax (or a tax at a reduced rate under an applicable income tax treaty) on such gain (net of certain U.S. source losses); or

&nbsp;&nbsp;&nbsp;&nbsp;• IGM is or has been a "United States real property holding corporation" ("USRPHC") for U.S. federal income tax purposes at any time during the shorter of the five-year period ending on the date of the Offer or the Merger or the period during which the Non-U.S. Holder held Shares, and, if Shares are regularly traded on an established securities market (within the meaning of Section 897(c)(3) of the Code), such Non-U.S. Holder owns directly or is deemed to own pursuant to attribution rules more than 5% of the Shares at any time during the relevant period, in which case such gain will be subject to U.S. federal income tax at rates generally applicable to U.S. persons (as described in the first bullet point above), except that the branch profits tax will not apply. Although there can be no assurances in this regard, IGM believes that it is not, and has not been, a USRPHC at any time during the five-year period preceding the Offer and the Merger.

Generally, if payments are made to a Non-U.S. Holder with respect to a CVR, such Non-U.S. Holder may be subject to withholding at a rate of 30% (or a lower applicable treaty rate) on the portion of any such payments treated as imputed interest (as discussed above under "<u>U.S. Holders—Imputed Interest</u>"), unless such Non-U.S. Holder establishes its entitlement to exemption from or a reduced rate of withholding under an applicable tax treaty by providing the appropriate documentation (generally, IRS Form W-8BEN or W-8BEN-E or other applicable IRS Form W-8) to the applicable withholding agents. As discussed above, the tax treatment of the CVRs is unclear, and it is possible that the Depositary and Paying Agent or other withholding agent may withhold additional amounts on payments with respect to the CVRs.

Amounts treated as imputed interest that are effectively connected with a Non-U.S. Holder's conduct of a trade or business in the United States and, if required by an applicable income tax treaty, are attributable to a permanent establishment in the United States, are generally taxed in the manner applicable to U.S. Holders, as described above. In such cases, the Non-U.S. Holder will not be subject to withholding so long as such Non-U.S. Holder complies with applicable certification and disclosure requirements. In addition, interest received by a non-U.S. corporation that are effectively connected with the conduct of a trade or business in the United States may be subject to a branch profits tax at a 30% rate, or a lower rate specified in an applicable income tax treaty. See "<u>The Tender Offer—Section 3. Procedures for Tendering Shares</u>" for information regarding the application of U.S. federal income tax withholding to payments made to Non-U.S. Holders.

If any amounts withheld exceed the Non-U.S. Holder's U.S. federal income tax liability, such Non-U.S. Holder may obtain a refund or credit of any excess amounts withheld by filing an appropriate claim for a refund with the IRS.

Non-U.S. Holders are urged to consult their own tax advisors regarding the particular tax consequences to them of exchanging Shares in the Offer or the Merger, including the application of the 30% U.S. federal withholding tax, their potential eligibility for a reduced rate of, or exemption from, such withholding tax, and their potential eligibility for, and procedures for claiming, a refund of any such withholding tax.

**Information Reporting, Backup Withholding and FATCA. Information reporting generally will apply to payments to a Holder pursuant to the Offer or the Merger (including payments with respect to a CVR), unless such Holder is an entity that is exempt from information reporting and, when required, properly demonstrates its** 

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eligibility for exemption. Any payment to a U.S. Holder that is subject to information reporting generally will also be subject to backup withholding, unless such U.S. Holder: (i) provides the appropriate documentation (generally, IRS Form W-9) to the applicable withholding agent certifying that, among other things, its taxpayer identification number is correct, or otherwise establishes an exemption; and (ii) with respect to payments on the CVRs, provides the rights agent with the certification documentation in clause (i) of this sentence or otherwise establishes an exemption from backup withholding tax.

The information reporting and backup withholding rules that apply to payments to a Holder pursuant to the Offer and Merger generally will not apply to payments to a Non-U.S. Holder if such Non-U.S. Holder certifies under penalties of perjury that it is not a U.S. person (generally by providing an IRS Form W-8BEN, IRS Form W-8BEN-E or other applicable IRS Form W-8) or otherwise establishes an exemption. Non-U.S. Holders should consult their own tax advisors to determine which IRS Form W-8 is appropriate.

As discussed above, we intend to send to each U.S. Holder an IRS Form 1099-B treating the Offer or the Merger, as applicable, as a "closed transaction" for U.S. federal income tax purposes. Accordingly, U.S. Holders that treat the Offer or the Merger, as applicable, as an "open transaction" for U.S. federal income tax purposes are urged to consult their own tax advisors regarding how to accurately report their income under this method. Certain Holders (including corporations) generally are not subject to backup withholding. Backup withholding is not an additional tax. Any amounts withheld under the backup withholding rules generally will be allowed as a refund or a credit against a U.S. Holder's U.S. federal income tax liability if the required information is properly and timely furnished by such U.S. Holder to the IRS.

Under the "Foreign Account Tax Compliance Act" provisions of the Code, related U.S. Treasury guidance and related intergovernmental agreements ("<u>FATCA</u>"), the Depositary and Paying Agent or another applicable withholding agent will be required to withhold tax at a rate of 30% on payments of amounts treated as interest pursuant to U.S. tax law to any Non-U.S. Holder that fails to meet prescribed certification requirements. In general, no such withholding will be required with respect to a person that timely provides certifications that establish an exemption from FATCA withholding on a valid IRS Form W-8. A Non-U.S. Holder may be able to claim a credit or refund of the amount withheld under certain circumstances. Under currently proposed Treasury Regulations, FATCA withholding would no longer apply to payments that are treated as gross proceeds from the sale or other disposition of property of a type that can generate U.S. source interest or dividends, including the Shares. Taxpayers generally may rely on these proposed Treasury Regulations until final Treasury Regulations are issued. Each Non-U.S. Holder should consult its own tax advisor regarding the application of FATCA to the CVRs.

**THE FOREGOING SUMMARY DOES NOT PURPORT TO BE A COMPLETE DISCUSSION OF THE POTENTIAL TAX CONSEQUENCES OF THE OFFER OR THE MERGER OR THE OWNERSHIP OF CVRS. EACH HOLDER SHOULD CONSULT ITS OWN TAX ADVISOR REGARDING THE U.S. FEDERAL, STATE AND LOCAL AND NON-U.S. INCOME, ESTATE AND OTHER TAX CONSIDERATIONS RELATING TO THE OFFER AND MERGER IN LIGHT OF ITS PARTICULAR CIRCUMSTANCES. THE U.S. FEDERAL, STATE, LOCAL AND NON-U.S. INCOME AND OTHER TAX CONSEQUENCES TO HOLDERS OR BENEFICIAL OWNERS OF COMPANY STOCK OPTIONS OR COMPANY RESTRICTED STOCK UNITS PARTICIPATING IN THE MERGER WITH RESPECT TO SUCH COMPANY STOCK OPTIONS OR COMPANY RESTRICTED STOCK UNITS ARE NOT DISCUSSED HEREIN, AND SUCH HOLDERS OR BENEFICIAL OWNERS OF COMPANY STOCK OPTIONS OR COMPANY RESTRICTED STOCK UNITS ARE STRONGLY ENCOURAGED TO CONSULT THEIR OWN TAX ADVISORS REGARDING SUCH TAX CONSEQUENCES. NOTHING IN THIS SUMMARY IS INTENDED TO BE, OR SHOULD BE CONSTRUED AS, TAX ADVICE.** 

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#### THE TENDER OFFER
1. **TERMS OF THE OFFER.** 

Upon the terms and subject to the prior satisfaction or waiver of the conditions of the Offer (including, if the Offer is extended or amended, the terms and conditions of any extension or amendment), we will accept for payment, purchase and pay for all Shares validly tendered prior to the expiration of the Offer, and not properly withdrawn in accordance with the procedures set forth in "<u>The Tender Offer—Section 4. Withdrawal Rights</u>." The Offer will expire at one minute after 11:59 p.m. Eastern Time on August 13, 2025, unless extended in accordance with the terms of the Merger Agreement, in which event the term "<u>Expiration Date</u>" will mean the date to which the Expiration Date of the Offer is so extended.

Purchaser is offering to pay: (i) $1.247 per Share in cash (the "<u>Cash Amount</u>"); and (ii) one non-transferable contractual contingent value right for each Share (each, a "<u>CVR</u>", and each CVR together with the Cash Amount, the "<u>Offer Price</u>") which represents the right to receive one or more contingent cash payments equal to a pro rata share of: (i) 80% of the net proceeds from a disposition of (a) IGM's product candidates known as: (A) imvotamab, an IgM-based CD20 X CD3 bispecific antibody T cell engager; (B) IGM-2644, an IgM-based CD38 X CD3 bispecific T cell engager; (C) aplitabart (or IGM-8444), a Death Receptor 5 agonist; (D) IGM-7354, a targeted IL-15/IL-15R IgM antibody; (E) IGM-8447, an IgM-based Death Receptor 5 agonist; and (F) IGM-2537, an IgM-based CD123 X CD3 bispecific antibody T cell engager; or (b) patents and patent applications owned or controlled by the Company immediately prior to the closing of the Merger and set forth on Schedule 1 of the CVR Agreement, together with all patents issuing thereon or claiming priority thereto, in each case, that occurs within one (1) year following closing the Merger Closing Date, and such proceeds are received by or otherwise due to Parent or any of its Affiliates within one (1) year following the Merger Closing Date; and (ii) 100% of the Closing Net Cash in excess of $82,000,000, as determined five (5) business days prior to the Merger Closing Date, each pursuant to the CVR Agreement, in each case, all upon the terms and subject to the conditions described in this Offer to Purchase and in the related Letter of Transmittal. Subject to the terms of the Merger Agreement and CVR Agreement, the Offer Price will be paid net of any applicable tax withholding and without interest.

**As noted in the Summary Term Sheet, there is a risk that you may receive no payments under the CVRs. Therefore, in making a decision to tender your Shares, you should understand that if the CVR does not generate any payments, the only consideration that you would receive is the Cash Amount of $1.247 per Share that is being offered pursuant to the Offer. You should base your tender decision on the Cash Amount as it may be the only consideration you receive in the Offer. On July 15, 2025, the last full trading day prior to the date of this Offer to Purchase, the closing price of IGM's common stock as reported on Nasdaq was $1.35 per Share.** 

**The Offer is conditioned upon the satisfaction of the Minimum Tender Condition and the other conditions described in "<u>The Tender Offer—Section 9. Conditions of the Offer</u>." We may terminate the Offer without purchasing any Shares if certain events described in "<u>The Tender Offer—Section 7.</u> <u>Summary of the Merger Agreement and Certain Other Agreements—Summary of the Merger</u> <u>Agreement—Termination</u>" occur.** 

Purchaser expressly reserves the right, in its sole discretion, to: (i) waive, in whole or in part, any Offer Condition (including the Minimum Cash Condition), other than the Minimum Tender Condition or the Termination Condition; and/or (ii) modify the terms of the Offer in a manner not inconsistent with the Merger Agreement, except that IGM's consent is required for Purchaser to:

(A)<br> reduce the number of Shares subject to the Offer;

(B)<br> reduce the Offer Price;

(C)<br> waive, amend or modify the Termination Condition or the Minimum Tender Condition;

(D) add to the Offer Conditions or impose any other conditions on the Offer or amend, modify or supplement any Offer Condition in any manner adverse to the holders of the Shares, or that would, individually or in the aggregate, reasonably be expected to prevent or materially delay the consummation of the Offer or prevent, materially delay or materially impair the ability of Parent to consummate the Offer of the Merger; 

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(E)<br> terminate, extend or otherwise amend or modify the Expiration Date of the Offer other than as provided in the Merger Agreement;

(F)<br> change the form or terms of consideration payable in the Offer;

(G)<br> otherwise amend, modify or supplement any of the terms of the Offer in any manner adverse to the holders of Shares; or

(H)<br> provide for any "subsequent offering period" within the meaning of Rule 14d-11 under the Exchange Act.

Upon the terms and subject to the satisfaction or waiver of the conditions of the Offer and the Merger Agreement, including the Minimum Tender Condition, Purchaser will accept for payment and thereafter pay for all Shares validly tendered and not properly withdrawn pursuant to the Offer promptly after the Expiration Date. The Offer will not permit Shares to be tendered pursuant to guaranteed delivery procedures.

If, on or before the Expiration Date, we increase the consideration being paid for Shares accepted for payment in the Offer, such increased consideration will be paid to all stockholders whose Shares are purchased in the Offer, whether or not such Shares were tendered before the announcement of the increase in consideration. We also expressly reserve the right to modify the terms of the Offer, subject to compliance with the Exchange Act, the Merger Agreement and the restrictions identified in paragraphs (A) through (H) above.

The Merger Agreement provides that, unless the Merger Agreement has been validly terminated in accordance with its terms, (A) Purchaser may elect to (and if so requested by IGM, Purchaser will) extend the Offer for one or more consecutive increments of such duration as requested by IGM, but not more than 10 business days each, if at the scheduled Expiration Date of the Offer (i) any of the Offer Conditions (as set forth in "<u>The Tender Offer—Section 9. Conditions of the Offer</u>") shall not have been satisfied or waived, until such time as such conditions shall have been satisfied or waived or (ii) the determination of the Closing Net Cash and resolution of any dispute thereof has not been finalized in accordance with the terms of the Merger Agreement, and (B) Purchaser shall extend the Offer for the minimum period required by any rule, regulation or interpretation or position of the SEC or the staff thereof or Nasdaq applicable to the Offer; <u>provided</u> that Purchaser shall not, and shall not be required to, extend the Offer beyond 11:59 p.m., Eastern Time, on September 29, 2025 (the "<u>Outside Date</u>").

See "<u>The Tender Offer—Section 7. Summary of the Merger Agreement and Certain Other Agreements</u>."

Except as set forth above, there can be no assurance that we will be required under the Merger Agreement to extend the Offer. During any extension of the initial offering period pursuant to the paragraphs above, all Shares previously tendered and not withdrawn will remain subject to the Offer and subject to withdrawal rights. See "<u>The Tender Offer—Section 4. Withdrawal Rights</u>."

Without IGM's consent, there will not be a subsequent offering period for the Offer.

If, subject to the terms of the Merger Agreement, we make a material change in the terms of the Offer or the information concerning the Offer, or if we waive a material condition of the Offer, we will disseminate additional tender offer materials and extend the Offer if and to the extent required by Rules 14d-3(b)(1), 14d-4(d), 14d-6(c) and l4e-1 under the Exchange Act or otherwise. The minimum period during which a tender offer must remain open following material changes in the terms of the tender offer or the information concerning the tender offer, other than a change in the consideration offered or a change in the percentage of securities sought, will depend upon the facts and circumstances, including the relative materiality of the terms or information changes. With respect to a change in the consideration offered or a change in the percentage of securities sought, a tender offer generally must remain open for a minimum of 10 business days following the disclosure of such change to stockholders to allow for adequate disclosure to stockholders.

We expressly reserve the right, in our sole discretion, subject to the terms and upon the conditions of the Merger Agreement and the applicable rules and regulations of the SEC, to not accept for payment any Shares if, at the expiration of the Offer, any of the conditions to the Offer set forth in "<u>The Tender Offer—Section 9.</u> <u>Conditions of the Offer</u>" have not been satisfied. Under certain circumstances, Parent and Merger Sub may terminate the Merger Agreement and the Offer.

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Any extension, waiver or amendment of the Offer or termination of the Offer will be followed, as promptly as practicable, by public announcement thereof, such announcement in the case of an extension to be issued not later than 9:00 a.m. Eastern Time on the next business day after the Expiration Date in accordance with the public announcement requirements of Rules 14d-3(b)(1), 14d-4(d) and 14e-1(d) under the Exchange Act. Without limiting our obligation under such rule or the manner in which we may choose to make any public announcement, we currently intend to make announcements by issuing a press release to the PR Newswire (or such other national media outlet or outlets we deem prudent) and making any appropriate filing with the SEC.

Promptly following the purchase of Shares in the Offer, we expect to complete the Merger without a vote of the stockholders of IGM pursuant to Section 251(h) of the DGCL.

IGM has agreed to provide us with its list of stockholders and security position listings for the purpose of disseminating the Offer to holders of Shares. This Offer to Purchase and the related Letter of Transmittal will be mailed to record holders of Shares whose names appear on IGM's stockholder list and will be furnished to brokers, dealers, commercial banks, trust companies and similar persons whose names, or the names of whose nominees, appear on the stockholder list or, if applicable, who are listed as participants in a clearing agency's security position listing, for subsequent transmittal to beneficial owners of Shares.

2. **ACCEPTANCE FOR PAYMENT AND PAYMENT FOR SHARES.** 

Subject to the satisfaction or waiver of all the conditions to the Offer set forth in "<u>The Tender</u> <u>Offer—Section 9. Conditions of the Offer</u>," we will immediately after the Expiration Date irrevocably accept for payment all Shares tendered (and not validly withdrawn) pursuant to the Offer and, promptly after the Expiration Date (and in any event within three business days), pay for such Shares.

In all cases, payment for Shares tendered and accepted for payment pursuant to the Offer will be made only after timely receipt by the Depositary and Paying Agent of: (i) certificates (if any) representing such Shares or confirmation of the book-entry transfer of such Shares into the Depositary and Paying Agent's account at DTC pursuant to the procedures set forth in "<u>The Tender Offer—Section 3. Procedures for Tendering Shares</u>;" (ii) a Letter of Transmittal, properly completed and duly executed, with any required signature guarantees (or, in the case of a book-entry transfer, an Agent's Message (as defined below) in lieu of the Letter of Transmittal); and (iii) any other documents required by the Letter of Transmittal or any other customary documents required by Depositary and Paying Agent. See "<u>The Tender Offer—Section 3. Procedures for Tendering Shares</u>."

For purposes of the Offer, if and when Purchaser gives written notice to the Depositary and Paying Agent of its acceptance for payment of such Shares pursuant to the Offer, then Purchaser has accepted for payment and thereby purchased Shares validly tendered and not properly withdrawn pursuant to the Offer. Upon the terms and subject to the conditions of the Offer, payment for Shares accepted for payment pursuant to the Offer will be made by deposit of the purchase price therefor with the Depositary and Paying Agent, which will act as agent for the tendering stockholders for purposes of receiving payments from us and transmitting such payments to the tendering stockholders. **Under no circumstances will interest be paid on the Offer Price for Shares, regardless of any extension of the Offer or any delay in payment for Shares**.

If any tendered Shares are not accepted for payment pursuant to the terms and conditions of the Offer for any reason, or if certificates are submitted for more Shares than are tendered, certificates for such unpurchased Shares will be returned (or new certificates for the Shares not tendered will be sent), without expense to the tendering stockholder (or, in the case of Shares tendered by book-entry transfer into the Depositary and Paying Agent's account at DTC pursuant to the procedures set forth in "<u>The Tender Offer—Section 3. Procedures for</u> <u>Tendering Shares</u>," such Shares will be credited to an account maintained with DTC) promptly following expiration or termination of the Offer.

3. **PROCEDURES FOR TENDERING SHARES.** 

**Valid Tender of Shares. To validly tender Shares pursuant to the Offer, a properly completed and duly executed Letter of Transmittal in accordance with the instructions of the Letter of Transmittal, with any required signature guarantees, or an Agent's Message (as defined below) in connection with a book-entry delivery of Shares, and any other documents required by the Letter of Transmittal and any other customary documents required by the Depositary and Paying Agent, must be received by the Depositary and Paying Agent at one of its addresses set forth on the back cover of this Offer to Purchase prior to the expiration of the Offer and either:** 

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(i) certificates (if any) representing Shares tendered must be delivered to the Depositary and Paying Agent; or (ii) such Shares must be properly delivered pursuant to the procedures for book-entry transfer described below and a confirmation of such delivery received by the Depositary and Paying Agent (which confirmation must include an Agent's Message (as defined below)), in each case, prior to the Expiration Date. The term "<u>Agent's</u> <u>Message</u>" means a message, transmitted by DTC to, and received by, the Depositary and Paying Agent and forming a part of a Book-Entry Confirmation (as defined below), which states that DTC has received an express acknowledgment from the participant in DTC tendering the Shares which are the subject of such Book-Entry Confirmation (as defined below) that such participant has received and agrees to be bound by the terms of the Letter of Transmittal and that Purchaser may enforce such agreement against the participant.

**Book-Entry Transfer. The Depositary and Paying Agent will take steps to establish and maintain an account with respect to the Shares at DTC for purposes of the Offer. Any financial institution that is a participant in DTC's systems may make a book-entry transfer of Shares by causing DTC to transfer such Shares into the Depositary and Paying Agent's account in accordance with DTC's procedures for such transfer. An Agent's Message in lieu of the Letter of Transmittal, and any other required documents, must, in any case, be transmitted to and received by the Depositary and Paying Agent at one of its addresses set forth on the back cover of this Offer to Purchase prior to the Expiration Date. The confirmation of a book-entry transfer of Shares into the Depositary and Paying Agent's account at DTC as described above is referred to herein as a "<u>Book-Entry</u> <u>Confirmation</u>."** 

#### Delivery of documents to DTC in accordance with DTC's procedures does not constitute delivery to the Depositary and Paying Agent.
**Signature Guarantees. Except as otherwise provided below, all signatures on a Letter of Transmittal must be guaranteed by a financial institution (including most commercial banks, savings and loan associations and brokerage houses) that is a member in good standing of a recognized Medallion Program approved by the Securities Transfer Association, Inc., including the Security Transfer Agents Medallion Program, the New York Stock Exchange Medallion Signature Program and the Stock Exchanges Medallion Program (each, an "<u>Eligible</u> <u>Institution</u>"). Signatures on a Letter of Transmittal need not be guaranteed: (i) if the Letter of Transmittal is signed by the registered owner(s) of Shares tendered therewith and such registered owner has not completed the box entitled "<u>Special Payment Instructions</u>" or the box entitled "<u>Special Delivery Instructions</u>" on the Letter of Transmittal; or (ii) if such Shares are tendered for the account of an Eligible Institution. See Instructions 1 and 5 of the Letter of Transmittal. If the certificates for Shares are registered in the name of a person other than the signer of the Letter of Transmittal, or if payment is to be made or certificates for Shares not tendered or not accepted for payment are to be returned to a person other than the registered owner of the certificates surrendered, then signature(s) must be guaranteed as described above. See Instructions 1 and 5 of the Letter of Transmittal.** 

If certificates representing Shares are forwarded separately to the Depositary and Paying Agent, a properly completed and duly executed Letter of Transmittal must accompany each delivery of certificates.

**THE METHOD OF DELIVERY OF SHARES, THE LETTER OF TRANSMITTAL AND ALL OTHER REQUIRED DOCUMENTS, INCLUDING DELIVERY THROUGH DTC, IS AT THE ELECTION AND RISK OF THE TENDERING STOCKHOLDER. DELIVERY OF ALL SUCH DOCUMENTS WILL BE DEEMED MADE ONLY WHEN ACTUALLY RECEIVED BY THE DEPOSITARY (INCLUDING, IN THE CASE OF A BOOK-ENTRY TRANSFER, BY BOOK-ENTRY CONFIRMATION). IF SUCH DELIVERY IS BY MAIL, IT IS RECOMMENDED THAT ALL SUCH DOCUMENTS BE SENT BY PROPERLY INSURED REGISTERED MAIL WITH RETURN RECEIPT REQUESTED. IN ALL CASES, SUFFICIENT TIME SHOULD BE ALLOWED TO ENSURE TIMELY DELIVERY.** 

**Other Requirements. Purchaser will pay for Shares tendered (and not validly withdrawn) pursuant to the Offer only after timely receipt by the Depositary and Paying Agent of: (i) certificates (if any) for (or a timely Book-Entry Confirmation with respect to) such Shares; (ii) a Letter of Transmittal, properly completed and duly executed, with any required signature guarantees (or, in the case of a book-entry transfer, an Agent's Message in lieu of the Letter of Transmittal); and (iii) any other documents required by the Letter of Transmittal or any other customary documents required by the Depositary and Paying Agent. Under no circumstances will Purchaser** 

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**pay interest on the purchase price of Shares, regardless of any extension of the Offer or any delay in making such payment. If your Shares are held in street name (*i.e.*, through a broker, dealer, commercial bank, trust company or other nominee), your Shares can be tendered by your nominee by book-entry transfer through the Depositary and Paying Agent.** 

**Binding Agreement. Our acceptance for payment of Shares tendered pursuant to one of the procedures described above will constitute a binding agreement between the tendering stockholder and us upon the terms and subject to the conditions of the Offer.** 

**Appointment as Proxy. By executing and delivering a Letter of Transmittal as set forth above (or, in the case of a book-entry transfer, by delivery of an Agent's Message in lieu of a Letter of Transmittal), the tendering stockholder irrevocably appoints Purchaser's designees as such stockholder's proxies, each with full power of substitution, to the full extent of such stockholder's rights with respect to the Shares tendered by such stockholder and accepted for payment by us and with respect to any and all other Shares or other securities issued or issuable in respect of such Shares on or after the date of the Merger Agreement. All such proxies and powers of attorney will be considered coupled with an interest in the tendered Shares. Such appointment is effective when, and only to the extent that, we accept for payment Shares tendered by such stockholder as provided herein. Upon the effectiveness of such appointment, all prior powers of attorney, proxies and consents given by such stockholder will be revoked, and no subsequent powers of attorney, proxies and consents may be given (and, if given, will not be deemed effective). Our designees will, with respect to the Shares or other securities and rights for which the appointment is effective, be empowered to exercise all voting and other rights of such stockholder as they, in their sole discretion, may deem proper at any annual, special, adjourned or postponed meeting of the stockholders of IGM, by written consent in lieu of any such meeting or otherwise. We reserve the right to require that, in order for Shares to be deemed validly tendered, immediately upon our payment for such Shares we must be able to exercise full voting, consent and other rights to the extent permitted under applicable law with respect to such Shares and other securities, including voting at any meeting of stockholders or executing a written consent concerning any matter.** 

**Determination of Validity. All questions as to the validity, form, eligibility (including time of receipt) and acceptance of any tender of Shares will be determined by us in our sole and absolute discretion (which may delegate power in whole or in part to the Paying and Depositary Agent), which determination will be final and binding, subject to the rights of the tendering holders of Shares to challenge our determination in a court of competent jurisdiction. Purchaser reserves the absolute right to reject any and all tenders determined by us not to be in proper form or the acceptance for payment of or payment for which may, in our opinion, be unlawful. Purchaser also reserves the absolute right to waive any defect or irregularity in the tender of any Shares of any particular stockholder whether or not similar defects or irregularities are waived in the case of any other stockholder. No tender of Shares will be deemed to have been validly made until all defects and irregularities relating thereto have been cured or waived. None of Parent, Merger Sub or any of their respective affiliates or assigns, the Depositary and Paying Agent, the Information Agent, or any other person will be under any duty to give notification of any defects or irregularities in tenders or incur any liability for failure to give any such notification. Purchaser's interpretation of the terms and conditions of the Offer (including the Letter of Transmittal and the instructions thereto and any other documents related to the Offer) will be final and binding, subject to the rights of the tendering holders of Shares to challenge our determination in a court of competent jurisdiction.** 

4. **WITHDRAWAL RIGHTS.** 

Except as otherwise provided in this <u>Section 4</u>, tenders of Shares pursuant to the Offer are irrevocable. However, a stockholder has withdrawal rights that are exercisable until the expiration of the Offer (*i.e.*, at any time prior to one minute after 11:59 p.m. Eastern Time on August 13, 2025), or in the event the Offer is further extended, on such date and time to which the Offer is extended. In addition, pursuant to Section 14(d)(5) of the Exchange Act, Shares may be withdrawn at any time after September 14, 2025, which is the 60<sup>th</sup> day after the date of the commencement of the Offer, unless prior to that date Purchaser has accepted for payment the Shares validly tendered in the Offer.

For a withdrawal of Shares to be effective, a written transmission notice of withdrawal must be timely received by the Depositary and Paying Agent at one of its addresses set forth on the back cover of this Offer to Purchase. Any notice of withdrawal must specify the name of the person having tendered the Shares to be

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withdrawn, the number of Shares to be withdrawn and the name of the record holder of the Shares to be withdrawn, if different from that of the person who tendered such Shares. The signature(s) on the notice of withdrawal must be guaranteed by an Eligible Institution, unless such Shares have been tendered for the account of any Eligible Institution. If Shares have been tendered pursuant to the procedures for book-entry transfer as set forth in "<u>The Tender Offer—Section 3. Procedures for Tendering Shares</u>," your nominee must submit your withdrawal through DTC to be credited with the withdrawn Shares. If certificates representing the Shares have been delivered or otherwise identified to the Depositary and Paying Agent, the name of the registered owner and the serial numbers shown on such certificates must also be furnished to the Depositary and Paying Agent prior to the physical release of such certificates.

All questions as to the form and validity (including time of receipt) of any notice of withdrawal will be determined by us, in our sole discretion (which may delegate power in whole or in part to the Paying and Depositary Agent), which determination will be final and binding, subject to the rights of the tendering holders of Shares to challenge our determination in a court of competent jurisdiction. No withdrawal of Shares will be deemed to have been properly made until all defects and irregularities have been cured or waived. None of Parent, Merger Sub or any of their respective affiliates or assigns, the Depositary and Paying Agent, the Information Agent, or any other person will be under any duty to give notification of any defects or irregularities in any notice of withdrawal or incur any liability for failure to give such notification. Withdrawals of tenders of Shares may not be rescinded, and any Shares properly withdrawn will be deemed not to have been validly tendered for purposes of the Offer. However, withdrawn Shares may be re-tendered by following one of the procedures for tendering Shares described in "<u>The Tender Offer—Section 3. Procedures for Tendering Shares</u>" at any time prior to the expiration of the Offer.

If Purchaser extends the Offer, delays its acceptance for payment of Shares, or is unable to accept for payment Shares pursuant to the Offer, for any reason, then, without prejudice to Purchaser's rights pursuant to the Offer, the Depositary and Paying Agent may nevertheless, on Purchaser's behalf, retain tendered Shares, and such Shares may not be withdrawn except to the extent that tendering stockholder's exercise of withdrawal rights as described in this <u>Section 4</u>.

5. **CERTAIN INFORMATION CONCERNING IGM.** 

The following description of IGM and its business has been taken from IGM's Annual Report on Form 10-K for the year ended December 31, 2024 filed with the SEC on March 6, 2025, the Amendment No. 1 to IGM's Annual Report on Form 10-K filed with the SEC on April 30, 2025, IGM's Quarterly Report on Form 10-Q for the quarter ended March 31, 2025 filed with the SEC on May 13, 2025, and IGM's Current Reports on Form 8-K filed with the SEC on January 10, 2025, March 6, 2025, May 8, 2025, May 23, 2025, June 6, 2025 and July 1, 2025, and is qualified in its entirety by reference to such Form 10-K, Form 10-Q and Forms 8-K, respectively.

IGM is a biotechnology company that has focused on developing engineered IgM-based therapeutic antibodies.

IGM was incorporated under the laws of the State of Delaware on August 25, 1993 under the name Palingen, Inc. The name was changed to IGM Biosciences, Inc. on October 13, 2010. IGM terminated its lease agreements for office space and, accordingly, IGM does not maintain headquarters. For purposes of compliance with applicable requirements of the Securities Act of 1933, as amended, and Securities Exchange Act of 1934, as amended, any stockholder communication required to be sent to IGM's principal executive offices may be sent to IGM Biosciences, Inc., 3 East Third Avenue, Suite 200, San Mateo, California 94401. IGM's telephone number is (650) 965-7873.

**Available Information. IGM is subject to the information and reporting requirements of the Exchange Act and in accordance therewith is obligated to file reports and other information with the SEC relating to its business, financial condition and other matters. Certain information, as of particular dates, concerning IGM's business, principal physical properties, capital structure, material pending litigation, operating results, financial condition, directors and officers (including their remuneration and stock options granted to them), the principal holders of IGM's securities, any material interests of such persons in transactions with IGM, and other matters is required to be disclosed in proxy statements and periodic reports distributed to IGM stockholders and filed with the SEC. The SEC maintains an Internet website that contains reports, proxy statements and other information about issuers, such as IGM, who file electronically with the SEC. The address of that site is https://www.sec.gov.** 

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IGM also maintains an Internet website at www.igmbio.com. The information contained in, accessible from or connected to IGM's website is not incorporated into, or otherwise a part of, this Offer to Purchase or any of IGM's filings with the SEC. The website addresses referred to in this paragraph are inactive text references and are not intended to be actual links to the websites.

**Sources of Information. Except as otherwise set forth herein, the information concerning IGM contained in this Offer to Purchase has been based upon publicly available documents and records on file with the SEC, other public sources and information provided by IGM. Although we have no knowledge that any such information contains any misstatements or omissions, none of the Guarantors, Parent, Merger Sub or any of their respective affiliates or assigns, the Information Agent or the Depositary and Paying Agent assumes responsibility for the accuracy or completeness of the information concerning IGM contained in such documents and records or for any failure by IGM to disclose events which may have occurred or may affect the significance or accuracy of any such information.** 

6. **CERTAIN INFORMATION CONCERNING PARENT AND MERGER SUB.** 

**General. Parent is a Delaware limited liability company formed under the laws of the State of Delaware on March 8, 2023 with its principal offices located at 4747 Executive Drive, Suite 210, San Diego, California 92121. The telephone number of Parent is (858) 281-5372.** 

Merger Sub is a Delaware corporation with its principal offices located at 4747 Executive Drive, Suite 210, San Diego, California 92121. The telephone number of Merger Sub is (858) 281-5372. Merger Sub is a wholly owned subsidiary of Parent. Merger Sub has not engaged, and does not expect to engage, in any business other than in connection with the Offer and the Merger.

TCP is a Delaware limited partnership with its principal offices located at 4747 Executive Drive, Suite 210, San Diego, California 92121. The telephone number of TCP is (858) 200-3830.

TCM is the general partner of TCP and sole manager of Parent. TCM is a Delaware limited liability company with its principal offices located at 4747 Executive Drive, Suite 210, San Diego, California 92121. The telephone number of TCM is (858) 200-3830.

The name, citizenship, business address, business phone number, present principal occupation or employment and past material occupation, positions, offices or employment for at least the last five years for each director and each of the executive officers of Parent, Merger Sub, TCP and TCM (the "<u>Item 3 Persons</u>") and certain other information are set forth in <u>Schedule A</u> hereto.

During the last five (5) years, none of Parent, Merger Sub, TCP or TCM or, to the knowledge of Parent, Merger Sub and the Guarantors, any of the Item 3 Persons: (i) has been convicted in a criminal proceeding (excluding traffic violations or similar misdemeanors); or (ii) was a party to any judicial or administrative proceeding (except for matters that were dismissed without sanction or settlement and convictions that have been overturned on appeal) that resulted in a judgment, decree or final order enjoining the person from future violations of, or prohibiting activities subject to, federal or state securities laws, or a finding of any violation of such laws.

In the past sixty (60) days, TCP has not effected any transaction in the IGM Shares. Except as set forth in the preceding sentence or as otherwise described in this Offer to Purchase: (A) none of Parent, Merger Sub, TCP, TCM, any majority-owned subsidiary of Parent, Merger Sub, TCP or TCM or, to the knowledge of Parent, Merger Sub, TCP or TCM, any of the Item 3 Persons or any associate of any of the persons so listed beneficially owns or has any right to acquire, directly or indirectly, any Shares; and (B) none of Parent, Merger Sub, TCP or TCM or, to the knowledge of Parent, Merger Sub, TCP or TCM, any of the persons or entities referred to in clause (A) above nor any director, executive officer or subsidiary of any of the foregoing has effected any transaction in the Shares during the past 60 days. As of the date of this Offer to Purchase, TCP does not own any of the outstanding IGM Shares. As discussed in <u>Section 10 – "Background of the Offer; Contacts with IGM</u>," any Shares owned by directly or indirectly by Parent or Merger Sub as of immediately prior to the Effective Time will be cancelled in the Merger for no consideration (including that no CVRs will be issued in respect of such Shares). There are no restrictions on any IGM stockholder with respect to transferring or disposing of any such Shares prior to the Effective Time.

Except as otherwise described in this Offer to Purchase, none of Parent, Merger Sub or TCP or, to the knowledge of Parent, Merger Sub, TCP or TCM, any of the Item 3 Persons, has any contract, arrangement,

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understanding or relationship with any other person with respect to any securities of IGM, including, but not limited to, any contract, arrangement, understanding or relationship concerning the transfer or voting of such securities, finder's fees, joint ventures, loan or option arrangements, puts or calls, guarantees of loans, guarantees against loss, guarantees of profits, division of profits or loss or the giving or withholding of proxies.

Except as set forth in this Offer to Purchase, none of Parent, Merger Sub, TCP, TCM or, to the knowledge of Parent, Merger Sub, TCP or TCM, any of the Item 3 Persons, has had any business relationship or transaction with IGM or any of its executive officers, directors or affiliates that is required to be reported under the rules and regulations of the SEC applicable to the Offer. Except as set forth in this Offer to Purchase, there have been no contacts, negotiations or transactions between Parent, Merger Sub, TCP or TCM or any of their subsidiaries or, to the knowledge of Parent, Merger Sub, TCP, TCM, any of the Item 3 Persons, on the one hand, and IGM or its affiliates, on the other hand, concerning a merger, consolidation or acquisition, tender offer or other acquisition of securities, an election of directors or a sale or other transfer of a material amount of assets during the past two years.

**Available Information. Pursuant to Rule 14d-3 under the Exchange Act, Parent filed with the SEC a Tender Offer Statement on Schedule TO (the "<u>Schedule TO</u>"), of which this Offer to Purchase forms a part, and exhibits to the Schedule TO. Copies of the Schedule TO and the exhibits thereto, and reports, proxy statements and other information may be obtained by mail, upon payment of the SEC's customary charges, by writing to its principal office at 100 F Street, NE, Washington, DC 20549. The Schedule TO and the exhibits thereto, as well as other information filed by Parent with the SEC, are available at the SEC's website on the Internet at www.sec.gov that contains the Schedule TO and the exhibits thereto and other information that Purchaser has filed electronically with the SEC.** 

7. **SUMMARY OF THE MERGER AGREEMENT AND CERTAIN OTHER AGREEMENTS.** 

*Summary of the Merger Agreement.* 

The following summary of certain provisions of the Merger Agreement and all other provisions of the Merger Agreement discussed herein are qualified by reference to the Merger Agreement itself, which is incorporated herein by reference. The Merger Agreement was filed as Exhibit 2.1 to the Current Report on Form 8-K that IGM filed with the SEC on July 1, 2025. The Merger Agreement may be examined and copies may be obtained at the places and in the manner set forth in "<u>The Tender Offer—Section 6. Certain Information</u> <u>Concerning Parent and Merger Sub</u>." Stockholders and other interested parties should read the Merger Agreement for a more complete description of the provisions summarized below. Capitalized terms used herein and not otherwise defined have the respective meanings set forth in the Merger Agreement.

The Merger Agreement has been included to provide investors and security holders with information regarding its terms. It is not intended to provide any other factual information about IGM, Parent, Merger Sub or their respective subsidiaries and affiliates. The Merger Agreement contains representations and warranties by IGM, on the one hand, and Parent and Merger Sub, on the other hand, made solely for the benefit of the other. The assertions embodied in those representations and warranties are subject to qualifications and limitations agreed to by the respective parties in negotiating the terms of the Merger Agreement, including information in confidential disclosure schedules delivered in connection with the signing of the Merger Agreement. Moreover, certain representations and warranties in the Merger Agreement were made as of a specified date, may be subject to a contractual standard of materiality different from what might be viewed as material to investors, or may have been used for the purpose of allocating risk between IGM, on the one hand, and Parent and Merger Sub, on the other hand, rather than establishing matters as facts. Accordingly, the representations and warranties in the Merger Agreement should not be relied on by any persons as characterizations of the actual state of facts about IGM, Parent, Merger Sub or their respective subsidiaries or affiliates at the time they were made or otherwise. In addition, information concerning the subject matter of the representations and warranties may change after the date of the Merger Agreement, which subsequent information may or may not be fully reflected in IGM's public disclosures.

*The Offer. The Merger Agreement provides that Purchaser will commence the Offer no later than July 16, 2025. Purchaser's obligation to accept for payment and pay for Shares validly tendered in the Offer is subject only to the satisfaction of the Minimum Tender Condition and the other Offer Conditions that are described in "<u>The Tender Offer—Section 9. Conditions of the Offer</u>." Subject to the satisfaction of the Minimum Tender Condition and the other Offer Conditions that are described in "<u>The Tender Offer—Section 9. Conditions of the</u>*

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<u>Offer</u>," the Merger Agreement provides that Purchaser will promptly after the applicable Expiration Date, as it may be extended pursuant to the terms of the Merger Agreement, irrevocably accept for payment and pay for all Shares validly tendered and not properly withdrawn pursuant to the Offer. Parent is entitled to use or cause to be used some or all of the Closing Net Cash in order to pay the Offer Price for all such Shares.

Purchaser expressly reserves the right, in its sole discretion, to: (i) waive, in whole or in part, any Offer Condition described in "<u>The Tender Offer—Section 9. Conditions of the Offer</u>" (including the Minimum Cash Condition), other than the Minimum Tender Condition or the Termination Condition; and/or (ii) modify the terms of the Offer in a manner not inconsistent with the Merger Agreement, except that without IGM's prior written consent, Purchaser shall not:

(A)<br> reduce the number of Shares subject to the Offer;

(B)<br> reduce the Offer Price;

(C)<br> waive, amend or modify the Termination Condition or the Minimum Tender Condition;

(D) add to the Offer Conditions or impose any other conditions on the Offer or amend, modify or supplement any Offer Condition in any manner adverse to the holders of the Shares, or that would, individually or in the aggregate, reasonably be expected to prevent or materially delay the consummation of the Offer or prevent, materially delay or materially impair the ability of Parent to consummate the Offer of the Merger; 

(E)<br> terminate the Offer, extend or otherwise amend or modify the Expiration Date of the Offer other than as provided in the Merger Agreement;

(F)<br> change the form or terms of consideration payable in the Offer;

(G)<br> otherwise amend, modify or supplement any of the terms of the Offer in a manner adverse to the holders of Shares; or

(H)<br> provide any "subsequent offering period" in accordance with Rule 14d-11 of the Exchange Act.

The Merger Agreement provides that, unless the Merger Agreement has been validly terminated in accordance with its terms, Purchaser may elect to (and if so requested by IGM, Purchaser will) extend the Offer: (A) for one or more consecutive increments of such duration as requested by IGM (or if not requested by IGM, as determined by Parent), but not more than 10 business days each (or for such longer period as may be agreed to by Parent and IGM), if at the scheduled Expiration Date of the Offer (i) any of the Offer Conditions (as set forth in "<u>The Tender Offer—Section 9. Conditions of the Offer</u>") shall not have been satisfied or waived, until such time as such conditions shall have been satisfied or waived or (ii) the determination of the Closing Net Cash and resolution of any dispute thereof has not been finalized in accordance with the terms of the Merger Agreement, and (B) Purchaser shall extend the Offer for the minimum period required by any rule, regulation or interpretation or position of the SEC or the staff thereof or Nasdaq applicable to the Offer; <u>provided</u> that Purchaser not be permitted or required to extend the Offer beyond the Outside Date.

Unless the Merger Agreement is terminated in accordance with its terms, Purchaser shall not terminate or withdraw the Offer prior to any scheduled expiration date. In the event the Merger Agreement is validly terminated in accordance with its terms, Purchaser will promptly and irrevocably terminate the Offer and return and will cause any depository acting on behalf of Purchaser to return, all tendered Shares to the registered holders thereof.

*Conversion of Capital Stock at the Effective Time. Each outstanding Share, other than Shares held in the treasury by IGM, held by any stockholders, or owned by any beneficial owners, of IGM who are entitled to and who properly exercise appraisal rights under Delaware law or owned by Parent, Merger Sub or any other subsidiary of Parent at the commencement of the Offer and is owned by Parent, Merger Sub or any other subsidiary of Parent immediately prior to the Effective Time, will be converted into the right to receive the Offer Price, without interest and subject to any applicable tax withholding.* 

Each share of Merger Sub's capital stock issued and outstanding immediately prior to the Effective Time will be converted into and become one fully paid and nonassessable share of common stock, par value $0.01 per share, of the Surviving Corporation.

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*The Merger. The Merger Agreement provides that, as soon as practicable following the Offer Closing Time and subject to the terms and conditions of the Merger Agreement, and in accordance with the DGCL, at the Effective Time, Merger Sub will be merged with and into IGM, the separate existence of Merger Sub will cease and IGM will continue as the Surviving Corporation in the Merger. The Merger will be effected under Section 251(h) of the DGCL, without a vote on the adoption of the Merger Agreement by the holders of the Shares. Accordingly, Parent, Merger Sub and IGM have agreed to take all necessary and appropriate action to cause the Merger to become effective as soon as practicable following the consummation of the Offer without a vote of IGM stockholders in accordance with Section 251(h) of the DGCL, upon the terms and subject to the satisfaction or waiver of the conditions to the Merger.* 

Immediately following the Effective Time, the certificate of incorporation of IGM will be amended and restated in its entirety to be in the form attached as Exhibit B to the Merger Agreement and, as so amended and restated, will be the certificate of incorporation of the Surviving Corporation.

Immediately following the Effective Time, the bylaws of IGM will be amended and restated in its entirety to be in the form attached as Exhibit C to the Merger Agreement and, as so amended and restated, will be the bylaws of the Surviving Corporation.

*Treatment of Equity Awards. Pursuant to the Merger Agreement, as of immediately prior to the Effective Time, the vesting for each Company Stock Option and, as of immediately prior to the Offer Closing Time, the vesting for each Company Restricted Stock Unit, shall be accelerated and: (i) (A) each Company Stock Option that has an exercise price per share that is less than the Cash Amount (each, an "<u>In-the-Money Option</u>") that is then outstanding will be cancelled and, in exchange therefor, the holder of such cancelled In-the-Money Option will be entitled to receive in consideration of the cancellation of such In-the-Money Option (1) an amount in cash without interest, less any applicable tax withholding, equal to the product obtained by multiplying (x) the excess of the Cash Amount over the exercise price per share of Shares underlying such In-the-Money Option by (y) the number of Shares underlying such In-the-Money Option as of immediately prior to the Effective Time, and (2) one CVR for each Share subject thereto, and (B) each Company Stock Option that has an exercise price per share that is equal to or greater than the Cash Amount that is then outstanding will be cancelled for no consideration; and (ii) each Company Restricted Stock Unit that is then outstanding will be cancelled and, in exchange therefor, the holder of such cancelled Company Restricted Stock Unit will be entitled to receive in consideration of the cancellation of such Company Restricted Stock Unit an (1) amount in cash without interest, less any applicable tax withholding, equal to the Cash Amount, and (B) one CVR.* 

*Treatment of Company Pre-Funded Warrants. Prior to the Effective Time, IGM shall satisfy all of its notification requirements under the terms of each outstanding and unexercised Company Pre-Funded Warrant, and, at the Effective Time, each Company Pre-Funded Warrant shall be canceled and holders of such warrants will be entitled to receive: (1) an amount in cash without interest, less any applicable tax withholding, equal to the product obtained by multiplying (x) the excess of the Cash Amount over the exercise price per share of such Company Pre-Funded Warrant by (y) the number of Shares underlying such Company Pre-Funded Warrant as of immediately prior to the Effective Time; and (2) one CVR for each Share underlying such Company Pre-Funded Warrant.* 

*Conditions to Each Party's Obligation to Effect the Merger. The obligation of IGM, Parent and Merger Sub to effect the Merger is subject to the satisfaction or waiver on or prior to the Closing Date of the following conditions:* 

(i) there must not be any judgment issued, or other legal restraint or prohibition imposed, in each case, by any governmental entity of competent jurisdiction, or law, in each case, (collectively, "<u>Legal</u> <u>Restraints</u>") preventing or prohibiting the consummation of the Merger; and 

(ii)<br> Purchaser must have accepted for payment all Shares validly tendered and not properly withdrawn pursuant to the Offer.

*IGM Board Recommendation. As described above, and subject to the provisions described below, the IGM Board has determined to recommend that the stockholders of IGM accept the Offer and tender their Shares to* 

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Purchaser in the Offer. The foregoing recommendation is referred to herein as the "<u>IGM Board</u> <u>Recommendation</u>." The IGM Board also agreed to include the IGM Board Recommendation with respect to the Offer in the Schedule 14D-9 and has permitted Parent to refer to such recommendation in this Offer to Purchase and documents related to the Offer.

*Reasonable Best Efforts. Each of IGM, Parent and Merger Sub has agreed to use its respective reasonable best efforts to promptly take, or cause to be taken, and to do, or cause to be done, and to assist and cooperate with the other parties to the Merger Agreement in doing, all actions that are necessary, proper or advisable to consummate and make effective, as promptly as reasonably practicable and in any event prior to the Outside Date, the other transactions contemplated by the Merger Agreement (collectively, the "<u>Transactions</u>"). In particular, without limiting the generality of the foregoing, IGM, Parent and Merger Sub are required to use reasonable best efforts to: (i) cause each of the Offer Conditions and each of the conditions to the Merger to be satisfied as promptly as reasonably practicable; (ii) obtain all necessary or advisable actions or non-actions, waivers and consents from, or the making of all necessary registrations, declarations and filings with, and the taking of all reasonable steps as may be necessary to avoid a proceeding by, any governmental entity with respect to the Merger Agreement or the Transactions; (iii) defending or contesting of any proceedings, whether judicial or administrative, challenging the Merger Agreement or the consummation of the Transactions, including seeking to have any stay or temporary restraining order entered by any court or other governmental entity vacated or reversed; and (iv) executing and delivering any additional instruments necessary to consummate the Transactions and to fully carry out the purposes of the Merger Agreement.* 

*Termination. The Merger Agreement may be terminated prior to the Offer Closing Time as follows:* 

(i)<br> by mutual written consent of Parent, Merger Sub and IGM (in the case of IGM, upon approval of the IGM Board);

(ii)<br> by either Parent or IGM (in the case of IGM, upon approval of the IGM Board) if:

a. (A) the Offer Closing Time shall not have occurred on or before 11:59 p.m. Eastern Time on September 29, 2025 (the "<u>Outside Date</u>") or (B) the Offer shall have expired or been terminated in accordance with its terms and in accordance with the Merger Agreement without Purchaser having purchased any Shares; provided that the right to terminate the Merger Agreement shall not be available to any party if such occurrence is primarily due to a material breach of the Merger Agreement by such party; or 

b. any Legal Restraint permanently preventing or prohibiting the consummation of the Offer or the Merger shall be in effect and shall have become final and non-appealable; provided, that the right to terminate the Merger Agreement shall not be available to any party if such Legal Restraint is primarily due to such party's failure to comply in all material respects with its reasonable best efforts obligations under Section 7.02 of the Merger Agreement, as described above; 

(iii) by Parent, if IGM breaches or fails to perform any of its representations, warranties or covenants contained in the Merger Agreement, which breach or failure to perform individually or in the aggregate with all such other breaches or failures to perform (A) would result in the failure of an Offer Condition and (B) cannot be or has not been cured prior to the earlier of (x) 30 days after giving written notice to IGM of such breach or failure to perform and (y) the Outside Date; provided that Parent and Merger Sub are not then in material breach of the Merger Agreement (a "<u>IGM Breach</u> <u>Termination</u>"); 

(iv)<br> by Parent if an Adverse Recommendation Change has occurred;

(v) by Parent if the Closing Net Cash as finally determined pursuant to the Merger Agreement is less than $82,000,000 (a "<u>Minimum Cash Termination</u>"); 

(vi) by IGM (upon approval of the IGM Board), if (A) Purchaser fails to commence the Offer, except in the event of a violation by IGM of its obligations under the Merger Agreement, (B) Purchaser shall have terminated the Offer prior to its expiration date (as may be extended) other than in accordance with the Merger Agreement, or (C) all of the Offer Conditions have been satisfied or waived (other than those conditions that by their nature are to be satisfied at the time Purchaser consummates the 

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Offer, but subject to such conditions being able to be satisfied or waived) as of immediately prior to the expiration of the Offer and the Offer Closing Time shall not have occurred within five (5) business days following the expiration of the Offer;

(vii) by IGM (upon approval of the IGM Board), if Parent or Merger Sub breaches or fails to perform any of its representations, warranties or covenants contained in the Merger Agreement, which breach or failure to perform (A) had or would reasonably be expected to, individually or in the aggregate with all such other breaches or failures to perform, result in a Parent Material Adverse Effect (as defined in the Merger Agreement) and (B) cannot be or has not been cured prior to the earlier of (x) thirty (30) days after the giving of written notice to Parent or Merger Sub of such breach or failure to perform and (y) the Outside Date; provided that IGM is not then in material breach of the Merger Agreement; or 

(viii) by IGM (upon approval of the IGM Board), if (A) the IGM Board authorizes IGM to enter into a definitive written agreement constituting a Superior Company Proposal (as defined below), (B) the IGM Board have complied in all material respects with their obligations under the Merger Agreement in respect of such Superior Company Proposal and (C) IGM has paid, or simultaneously with the termination of the Merger Agreement pays, the Company Termination Fee (as defined below). 

&nbsp;&nbsp;&nbsp;&nbsp;• " <u>Superior Company Proposal</u> " means any written bona fide Company Takeover Proposal received after July 1, 2025 and that if consummated would result in a person or group (or the stockholders of any person) owning, directly or indirectly, (i) 50% or more of the aggregate voting power of the capital stock of IGM or of the surviving entity or the resulting direct or indirect parent of IGM or such surviving entity or (ii) 50% or more (based on the fair market value thereof, as determined in good faith by the IGM Board) of the assets of IGM on terms and conditions which the IGM Board determines, in good faith, after consultation with outside counsel and its independent financial advisor, (A) would reasonably be expected to be more favorable from a financial point of view to the IGM stockholders than the Transactions, taking into account all the terms and conditions (including all financial, regulatory, financing, conditionality, legal and other terms and conditions) of such proposal and the Merger Agreement; and (B) is reasonably likely to be completed.

*Termination Fee. IGM has agreed to pay Parent a termination fee of $2,425,000 (the "<u>Company</u> <u>Termination Fee</u>") if:* 

(i)<br> IGM terminates the Merger Agreement in connection with a Superior Company Proposal (as defined above) as described in clause (viii) of "<u>Termination</u>" above;

(ii)<br> Parent terminates the Merger Agreement in the event an Adverse Recommendation Change occurs; or

(iii) (A) after July 1, 2025, a *bona fide* Company Takeover Proposal is publicly proposed or announced or becomes publicly known or otherwise communicated to management of IGM or the IGM Board, and such Company Takeover Proposal is not publicly withdrawn or, if not publicly proposed or announced or communicated to the IGM Board or management, has been withdrawn (x) in the case of a termination due to a material breach of the Merger Agreement, four (4) business days prior to the final expiration date of the Offer or (y) in the case of a IGM Breach Termination, prior to the time of such breach, (B) the Merger Agreement is terminated due to the Offer Closing Time not having occurred on or before the Outside Date or a IGM Breach Termination, and (C) within twelve (12) months after such termination, IGM consummates, or enters into a definitive agreement with respect to, any Company Takeover Proposal. 

&nbsp;&nbsp;&nbsp;&nbsp;• For purposes of this " <u>Termination Fee</u> " (i) – (iii), the term " <u>Company Takeover Proposal</u> " means any inquiry, proposal or offer from any Person or group (other than Parent and its subsidiaries) relating to (i) any direct or indirect acquisition or purchase, in a single transaction or a series of related transactions, of (A) 50% or more (based on the fair market value thereof, as determined by the IGM Board) of the assets of IGM or (B) 50% or more of the aggregate voting power of the capital stock of IGM, (ii) any tender offer, exchange offer, merger, consolidation, business combination, recapitalization, liquidation, dissolution, binding share exchange or similar transaction involving IGM that, if consummated, would result in any Person or group (or the stockholders of any Person) beneficially

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owning, directly or indirectly, 50% or more of the aggregate voting power of the capital stock of IGM or of the surviving entity or the resulting direct or indirect parent of IGM or such surviving entity, other than, in each case, the Transactions or (iii) any combination of the foregoing.

IGM is obligated to pay to Parent an expense reimbursement payment equal to the reasonable and documented out-of-pocket fees and expenses incurred by or on behalf of Parent or its affiliates in connection with the Transactions and CVR Agreement up to a maximum of $500,000 if Parent terminates the Merger Agreement pursuant to a Minimum Cash Termination (the "<u>Expense Reimbursement Payment</u>").

In the event Parent receives the Company Termination Fee or Expense Reimbursement Payment, such receipt will be deemed to be liquidated damages for any and all losses or damages suffered or incurred by Parent or Merger Sub and constitute their sole and exclusive remedy against IGM and its current, former or future stockholders and representatives for any loss suffered as a result of the failure of the Transactions to be consummated, and none of IGM and its current, former or future stockholders or representatives will have any further liability or obligation relating to or arising out of the Merger Agreement or the Transactions, except as set forth in the Merger Agreement.

*Effect of Termination. If the Merger Agreement is terminated pursuant to its terms, the Merger Agreement will become void and have no effect and there will be no liability or obligation on the part of Parent, Merger Sub or IGM following any such termination, except that: (i) certain specified provisions of the Merger Agreement will survive, including those described in "<u>Termination Fee</u>" above; (ii) the confidentiality agreement by and among Parent and IGM will survive the termination of the Merger Agreement and remain in full force and effect in accordance with its terms; and (iii) termination will not relieve any party from liability for fraud or any willful and material breach of such party's representations, warranties, covenants or agreements set forth in the Merger Agreement.* 

*Conduct of Business Pending the Merger. IGM has agreed that, from the date of the Merger Agreement until the earlier of the Offer Closing Time and the termination of the Merger Agreement in accordance with its terms, except as specifically provided by the Merger Agreement or as consented to in writing in advance by Parent, IGM shall use commercially reasonable efforts to carry on its business in a manner consistent with the Wind-Down Process (as defined in the Merger Agreement) and otherwise in the ordinary course of business. In addition, except as set forth in the IGM Disclosure Letter or otherwise expressly and specifically permitted or required by the Merger Agreement or applicable law, from the date of the Merger Agreement until the earlier of the Offer Closing Time and the termination of the Merger Agreement in accordance with its terms, IGM shall not do any of the following without the prior written consent of Parent (which shall not be unreasonably withheld, delayed or conditioned):* 

&nbsp;&nbsp;&nbsp;&nbsp;• (i) enter into any new line of business or enter into any agreement, arrangement or commitment that is in excess of $50,000 (individually or in the aggregate) or materially limits or otherwise restricts IGM or its affiliates, including, following the Merger Closing, Parent and its affiliates (other than in the case of Parent and its affiliates, due to the operation of Parent's or its affiliates' own Contracts), from time to time engaging or competing in any line of business or in any geographic area; or (ii) otherwise enter into any agreements, arrangements or commitments in excess of $50,000 (individually or in the aggregate) or imposing material restrictions on its assets, operations or business;

&nbsp;&nbsp;&nbsp;&nbsp;• (i) declare, set aside, establish a record date in respect of, accrue or pay any dividends on, or make any other distributions (whether in cash, stock, equity securities or property) in respect of, any of its capital stock; (ii) split, combine or reclassify any of its capital stock or issue or authorize the issuance of any other securities in respect of, in lieu of or in substitution for shares of its capital stock; or (iii) repurchase, redeem, offer to redeem or otherwise acquire, directly or indirectly any shares of capital stock of IGM or options, warrants, convertible or exchangeable securities, stock-based performance units or other rights to acquire any such shares of capital stock, except for (A) acquisitions of Shares with the surrender of Shares by holders of Company Stock Options and Company Restricted Stock Units outstanding on the Agreement Date, in the case of Company Stock Options, in order to pay the exercise price of Company Stock Options, (B) the withholding of Shares to satisfy tax obligations

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with respect to awards granted pursuant to the Company Stock Plans (as defined in the Merger Agreement) outstanding on the Agreement Date, and (C) the acquisition by IGM of Company Stock Options and Company Restricted Stock Units in connection with the forfeiture of such awards, in each case, in accordance with their terms;

&nbsp;&nbsp;&nbsp;&nbsp;• issue, grant, deliver, sell, authorize, pledge or otherwise encumber any shares of its capital stock or options, warrants, convertible or exchangeable securities, stock-based performance units or other rights to acquire such shares, any Voting Company Debt or any other rights that give any person the right to receive any economic interest of any nature accruing to the holders of Shares, other than the Company Restricted Stock Units or the issuance of Shares upon the vesting of Company Restricted Stock Units and the issuance of Shares upon the exercise of Company Stock Options in accordance with their terms;

&nbsp;&nbsp;&nbsp;&nbsp;• amend its certificate of incorporation, the Company Bylaws (as defined in the Merger Agreement) or other comparable organizational documents;

&nbsp;&nbsp;&nbsp;&nbsp;• form any subsidiary or acquire or agree to acquire, directly or indirectly, in a single transaction or a series of related transactions, whether by merging or consolidating with, or by purchasing a substantial equity interest in or a substantial portion of the assets of, or by any other manner, any assets outside of the ordinary course of business, any business or any corporation, partnership, limited liability company, joint venture, association or other business organization or division thereof or any other Person;

&nbsp;&nbsp;&nbsp;&nbsp;• except as required pursuant to the terms of any Company Benefit Plan (as defined in the Merger Agreement) as in effect on the Agreement Date: (i) adopt, enter into, establish, terminate, amend or modify any collective bargaining agreement, Company Benefit Plan (or plan or arrangement that would be a Company Benefit Plan if in effect on the Agreement Date); (ii) grant to any director, employee or individual service provider of IGM any increase in base compensation; (iii) grant to any director, employee or individual service provider of IGM any increase in severance or termination pay; (iv) pay or award, or commit to pay or award, any bonuses or incentive or equity compensation; (v) enter into any employment, retention, consulting, change in control, severance or termination agreement with any director, employee or individual service provider of IGM; (vi) take any action to vest or accelerate any rights or benefits under any Company Benefit Plan, or the funding of any payments or benefits under any Company Benefit Plan; or (vii) hire or terminate (other than for cause) the employment or service of any employee or individual service provider;

&nbsp;&nbsp;&nbsp;&nbsp;• make any change in accounting methods, principles or practices, except as may be required: (i) by GAAP (or any authoritative interpretation thereof), including pursuant to standards, guidelines and interpretations of the Financial Accounting Standards Board or any similar organization; or (ii) by Law, including Regulation S-X promulgated under the Securities Act, in each case, as agreed to by IGM's independent public accountants;

&nbsp;&nbsp;&nbsp;&nbsp;• sell, lease (as lessor), license or otherwise transfer (including through any "spin-off"), or pledge, encumber or otherwise subject to any Lien (other than a Permitted Lien), any properties or assets (including Intellectual Property) except: (i) sales or other dispositions of inventory and excess or obsolete properties or assets in the ordinary course of business; (ii) pursuant to Contracts to which IGM is a party made available to Parent and in effect prior to the Agreement Date or (iii) in accordance with the Wind-Down Process;

&nbsp;&nbsp;&nbsp;&nbsp;• sell, assign, lease, license, transfer, pledge, encumber or otherwise dispose of, permit to lapse or abandon, or, in the case of Trade Secrets, disclose to any third party: (i) any Trade Secret included in any Intellectual Property owned by IGM; or (ii) other than in accordance with the Wind-Down Process, any Intellectual Property owned by IGM;

&nbsp;&nbsp;&nbsp;&nbsp;• (i) incur or modify the terms of (including by extending the maturity date thereof) any indebtedness for borrowed money or guarantee any such indebtedness of another Person, issue or sell any debt securities or warrants or other rights to acquire any debt securities of IGM, guarantee any debt securities of

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another Person, enter into any "keep well" or other agreement to maintain any financial statement condition of another Person or enter into any arrangement having the economic effect of any of the foregoing; or (ii) make any loans, advances or capital contributions to, or investments in, any other Person;

&nbsp;&nbsp;&nbsp;&nbsp;• make or agree to make any capital expenditures;

&nbsp;&nbsp;&nbsp;&nbsp;• commence any Proceeding or pay, discharge, settle, compromise or satisfy: (i) any pending or threatened claims, liabilities or obligations relating to a Proceeding (absolute, accrued, asserted or unasserted, contingent or otherwise), other than any such payment, discharge, settlement, compromise or satisfaction of a claim solely for money damages in the ordinary course of business in an amount not to exceed $50,000 per payment, discharge, settlement, compromise or satisfaction or $50,000 in the aggregate for all such payments, discharges, settlements, compromises or satisfactions, provided such amounts are taken into account in the calculation of Closing Net Cash; or (ii) any litigation, arbitration, proceeding or dispute that relates to the Transactions (which shall be governed exclusively by Section 7.07 of the Merger Agreement);

&nbsp;&nbsp;&nbsp;&nbsp;• make, change or revoke any material Tax election, change any material annual Tax accounting period or adopt or change any material method of Tax accounting, file any amended Tax Return, fail to timely file any material Tax Return required to be filed (taking into account extensions obtained in the ordinary course of business) or pay any material Tax that is due or payable, enter into any closing agreement within the meaning of Section 7121 of the Code (or any similar provision of state, local or foreign Law), settle or compromise any material Tax liability or refund, incur any material liability for Taxes outside ordinary course of business, file any material Tax Return other than on a basis consistent with past practice unless required by applicable Law, consent to any extension or waiver of any limitation period with respect to any claim or assessment for material Taxes, grant any power of attorney with respect to Taxes, or enter into any Tax Sharing Agreement or any closing or other similar agreement;

&nbsp;&nbsp;&nbsp;&nbsp;• amend, cancel or terminate any insurance policy naming IGM as an insured, a beneficiary or a loss payable payee without obtaining comparable substitute insurance coverage;

&nbsp;&nbsp;&nbsp;&nbsp;• adopt a plan or agreement of complete or partial liquidation or dissolution, merger, consolidation, restructuring, recapitalization or other reorganization (other than the Merger);

&nbsp;&nbsp;&nbsp;&nbsp;• except in the ordinary course of business or in connection with any transaction to the extent specifically permitted by any other subclause of this Section 6.01, enter into, terminate or modify in any respect, or expressly release any rights under, any Material Contract or any Contract that, if existing on the Agreement Date, would have been a Material Contract;

&nbsp;&nbsp;&nbsp;&nbsp;• renew or enter into any agreement containing a non-compete, exclusivity, non-solicitation or similar clause that would restrict or limit, in any material respect, the operations of IGM; or

&nbsp;&nbsp;&nbsp;&nbsp;• authorize, commit or agree to take any of the foregoing actions.

*Access to Information. Except if prohibited by applicable law, during the period prior to the earlier of the Effective Time or the termination of the Merger Agreement in accordance with its terms, IGM will provide Parent and its Representatives reasonable access during normal business hours (under supervision of appropriate personnel and in a manner that does not unreasonably interfere with the normal operation of IGM's business) to its properties, books and records, contracts and personnel, and will furnish to Parent such information concerning IGM's business, properties and personnel as Parent or its representatives may reasonably request.* 

*Security Holder Litigation. In the event that any litigation commences or is threatened in writing by or on behalf of one or more stockholders of IGM against IGM and its directors relating to any Transaction, IGM has agreed to provide Parent an opportunity to review and propose comments to all material filings or responses to such litigation. Parent's consent is required for IGM to enter into, agree to or disclose any settlement with respect to any such litigation, except to the extent such settlement is covered by IGM's insurance policies or* 

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relates to the provision of additional disclosure in the Schedule 14D-9, but in each case, only if such settlement would not result in any restriction on the business or operations of IGM or its affiliates. IGM has an obligation to notify Parent of the commencement or written threat of any litigation and to keep Parent promptly and reasonably informed regarding any such litigation.

*Indemnification, Exculpation and Insurance. All rights to indemnification and exculpation from liabilities for acts or omissions occurring at or prior to the Effective Time, and rights to advancement of expenses, existing in favor of any person who is, becomes, or has ever been, a director, officer, employee or agent (including as a fiduciary with respect to an employee benefit plan) of IGM or its predecessors (each, an "<u>Indemnified Party</u>"), in each case, as provided in IGM's charter, bylaws or any indemnification agreement between IGM and an Indemnified Party: (i) will be assumed by the Surviving Corporation at the Effective Time; (ii) will survive the Merger; (iii) will continue in full force and effect in accordance with their terms; and (iv) for a period of six years following the date of the Merger Agreement, will not be amended, repealed or otherwise modified in any manner adverse to such Indemnified Party. Parent has agreed to ensure the Surviving Corporation complies with the foregoing obligations.* 

*Stock Exchange Delisting and Deregistration. As promptly as practicable following the Effective Time, the Surviving Corporation will cause IGM's securities to be de-listed from Nasdaq and de-registered under the Exchange Act.* 

*Section 16 Matters. Prior to the Effective Time, Parent will, and IGM may, take all steps as may be required to cause any dispositions or cancellations of IGM's equity securities in connection with the Merger Agreement or the Transactions by each individual who is a director or officer of IGM subject to Section 16 of the Exchange Act to be exempt under Rule 16b-3 under the Exchange Act.* 

*Takeover Laws. Parent, IGM and the IGM Board have agreed to: (i) take all actions within their power to ensure that no "business combination," "control share acquisition," "fair price," "moratorium" or other anti-takeover law (each, a "<u>Takeover Law</u>") is or becomes applicable to the Merger Agreement, the Offer, Offer Documents, the Merger or any of the other Transactions; and (ii) if any Takeover Law becomes applicable to the Merger Agreement, the Offer, Offer Documents, the Merger or any of the other Transactions, take all action within their power to ensure that the Offer, the Merger and the other Transactions may be consummated as promptly as practicable on the terms contemplated by the Merger Agreement and otherwise to minimize the effect of such statute or regulation on the Offer, the Merger and the other Transactions.* 

*Governance of the Surviving Corporation. Immediately following the Effective Time: (i) the directors of the Merger Sub immediately prior to the Effective Time will be appointed as the directors of the Surviving Corporation; and (ii) the officers of Merger Sub immediately prior to the Effective Time will become the officers of the Surviving Corporation.* 

*Public Announcements. Parent, Merger Sub and IGM have agreed to consult with each other before issuing, and provide each other the opportunity to review and comment upon, any press release or other public statements with respect to the Offer, the Merger and the other Transactions, and shall not issue any such press release or make any such public statement prior to such consultation, except as may be required by applicable law, court process or by obligations pursuant to any listing agreement with any national or foreign securities exchange.* 

*Representations and Warranties. This summary of the Merger Agreement has been included to provide investors with information regarding its terms. It is not intended to provide any other factual information about Parent, Merger Sub or IGM, their respective businesses, or the actual conduct of their respective businesses during the period prior to the consummation of the Offer or the Merger. The Merger Agreement contains representations and warranties that are the product of negotiations among the parties thereto and made to, and solely for the benefit of, each other as of the specified dates therein. The assertations embodied in those representations and warranties are subject to qualifications and limitations agreed to by the respective parties and are also qualified in important part by confidential disclosure scheduled delivered by IGM to Parent in connection with the Merger Agreement.* 

The representations and warranties were negotiated with the principal purpose of allocating risk among the parties to the agreements instead of establishing these matters as facts, and may be subject to standards of materiality applicable to the contracting parties that differ from those applicable to investors.

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In the Merger Agreement, IGM has made representations and warranties to Parent and Merger Sub with respect to, among other things:

&nbsp;&nbsp;&nbsp;&nbsp;• corporate matters, such as due organization, organizational documents, good standing, qualification,

&nbsp;&nbsp;&nbsp;&nbsp;• capitalization;

&nbsp;&nbsp;&nbsp;&nbsp;• subsidiaries;

&nbsp;&nbsp;&nbsp;&nbsp;• power and authority and enforceability;

&nbsp;&nbsp;&nbsp;&nbsp;• absence of conflicts and required consents and approvals;

&nbsp;&nbsp;&nbsp;&nbsp;• SEC filings, financial statements and absence of undisclosed liabilities;

&nbsp;&nbsp;&nbsp;&nbsp;• accuracy of information supplied for purposes of the Schedule 14D-9 and the Offer Documents;

&nbsp;&nbsp;&nbsp;&nbsp;• absence of certain changes (including a Company Material Adverse Effect (as defined below)) since March 31, 2025;

&nbsp;&nbsp;&nbsp;&nbsp;• taxes;

&nbsp;&nbsp;&nbsp;&nbsp;• material contracts;

&nbsp;&nbsp;&nbsp;&nbsp;• litigation;

&nbsp;&nbsp;&nbsp;&nbsp;• real property;

&nbsp;&nbsp;&nbsp;&nbsp;• compliance with laws;

&nbsp;&nbsp;&nbsp;&nbsp;• regulatory matters;

&nbsp;&nbsp;&nbsp;&nbsp;• environmental matters;

&nbsp;&nbsp;&nbsp;&nbsp;• labor matters;

&nbsp;&nbsp;&nbsp;&nbsp;• employee benefit plans;

&nbsp;&nbsp;&nbsp;&nbsp;• intellectual property;

&nbsp;&nbsp;&nbsp;&nbsp;• privacy and data security;

&nbsp;&nbsp;&nbsp;&nbsp;• brokers' fees and expenses

&nbsp;&nbsp;&nbsp;&nbsp;• absence of a stockholder rights plan and Takeover Laws;

&nbsp;&nbsp;&nbsp;&nbsp;• fairness opinion of financial advisor; and

&nbsp;&nbsp;&nbsp;&nbsp;• absence of any requirement for stockholder votes or consents in accordance with Section 251(h) of the DGCL.

Some of the representations and warranties in the Merger Agreement made by IGM are qualified as to "materiality" or a "Company Material Adverse Effect." For purposes of the Merger Agreement, a "<u>Company</u> <u>Material Adverse Effect</u>" means any change, event, condition, development, circumstance, state of facts, effect or occurrence that has a material adverse effect on (i) the business, financial condition, assets, properties or results of operations of IGM or (ii) the ability of IGM to consummate the Transactions. Solely with respect to the foregoing clause (i) of the definition of Company Material Adverse Effect, a Company Material Adverse Effect does not include or take into account any change, event, condition, development, circumstance, state of facts, effect or occurrence to the extent resulting from or arising out of:

(i)<br> general conditions (or changes therein) in the industries in which IGM operates;

(ii) general economic or regulatory, legislative or political conditions (or changes therein), including any actual or potential stoppage, shutdown, default or similar event or occurrence affecting a national or federal government, or securities, credit, banking, financial or other capital markets conditions (including changes generally in prevailing interest rates, currency exchange rates, credit markets or equity price levels or trading volumes), in each case, in the U.S., the European Union or elsewhere in the world; 

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(iii)<br> any change in applicable law or GAAP after the date of the Merger Agreement;

(iv)<br> geopolitical conditions, the outbreak or escalation of hostilities, any acts or threats of war (whether or not declared), sabotage or terrorism, or any escalation or worsening of any of the foregoing;

(v) any epidemic, pandemic, disease outbreak or other public health-related event (or escalation or worsening of any such events or occurrences, including, in each case, the response of Governmental Officials (or any actions or omissions which are taken in compliance with applicable Law or any directive, guideline or recommendation of any Governmental Officials, in each case in connection with any of the foregoing)), hurricane, tornado, flood, fire, volcano, earthquake or other natural or man-made disaster or any other national or international calamity, crisis or disaster; 

(vi) the failure, in and of itself, of IGM to meet any internal or external forward-looking projections, forecasts, estimates or predictions in respect of any financial or operating metrics before, on or after the date of the Merger Agreement, or changes in the market price or trading volume of the Shares or the credit rating of IGM (it being understood that the underlying facts giving rise or contributing to such failure or change may be taken into account in determining whether there has been a Company Material Adverse Effect if such facts are not otherwise excluded under this definition); 

(vii) the announcement, pendency or performance of any of the Transactions, including the identity of, or any facts or circumstances relating to, Parent, Merger Sub or their respective affiliates, any stockholder litigation (direct or derivative) in respect of the Merger Agreement or any of the Transactions and any loss of or change in relationship, contractual or otherwise, with any governmental entity, supplier, vendor, service provider, collaboration partner, licensor, licensee, landlord or any other party having business dealings with IGM, or departure of any employees or officers, of IGM; 

(viii)<br> IGM's compliance with the covenants contained in the Merger Agreement; or

(ix)<br> any action taken by IGM at Parent's express written request or with Parent's express written consent.

except in each case, with respect to clauses (i) through (v), to the extent IGM is disproportionately affected thereby as compared with other participants in the industries in which IGM operates (in which case the incremental disproportionate impact or impacts may be taken into account in determining whether there has been a Company Material Adverse Effect).

In the Merger Agreement, Parent and Merger Sub have made representations and warranties to IGM with respect to:

&nbsp;&nbsp;&nbsp;&nbsp;• corporate matters, such as due organization and good standing;

&nbsp;&nbsp;&nbsp;&nbsp;• power and authority and enforceability;

&nbsp;&nbsp;&nbsp;&nbsp;• absence of conflicts and required consents and approvals;

&nbsp;&nbsp;&nbsp;&nbsp;• accuracy of information supplied for purposes of the Schedule 14D-9 and the Offer Documents;

&nbsp;&nbsp;&nbsp;&nbsp;• broker's fees and expenses;

&nbsp;&nbsp;&nbsp;&nbsp;• litigation;

&nbsp;&nbsp;&nbsp;&nbsp;• ownership of certain IGM common stock; and

&nbsp;&nbsp;&nbsp;&nbsp;• the Limited Guaranty;

&nbsp;&nbsp;&nbsp;&nbsp;• sufficiency of funds;

&nbsp;&nbsp;&nbsp;&nbsp;• ownership of competing businesses; and

&nbsp;&nbsp;&nbsp;&nbsp;• foreign person status.

Some of the representations and warranties in the Merger Agreement made by Parent and Merger Sub are qualified as to "materiality" or a "Parent Material Adverse Effect." For purposes of the Merger Agreement, a "<u>Parent Material Adverse Effect</u>" means any change, effect, event or occurrence that prevents Parent or Merger Sub from consummating the Offer, the Merger and the other Transactions on or before the Outside Date.

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None of the representations, warranties, covenants or agreements in the Merger Agreement or in any instrument delivered pursuant to the Merger Agreement will survive the Effective Time, other than those covenants or agreements of the parties which by their terms apply, or are to be performed in whole or in part, after the Effective Time.

*Specific Performance. The parties have agreed that irreparable damage would occur in the event that any of the provisions of the Merger Agreement were not performed in accordance with their specific terms or were otherwise breached, and that monetary damages, even if available, would not be an adequate remedy therefor. The parties further agreed that the parties will be entitled to an injunction or injunctions, or any other appropriate form of equitable relief, to prevent breaches of the Merger Agreement and to enforce specifically the performance of the terms and provisions of the Merger Agreement in Chancery Court of the State of Delaware (or in any federal court located in the State of Delaware if jurisdiction is not then available in the Chancery Court of the State of Delaware) in addition to any other remedy to which they are entitled at law or in equity.* 

*Expenses. Except as otherwise provided in the Merger Agreement, all fees and expenses incurred by the parties in connection with the Merger Agreement and the Transactions will be paid by the party incurring such expenses, whether or not the Offer or the Merger is consummated.* 

*Offer Conditions. The Offer Conditions are described in "<u>The Tender Offer—Section 9. Conditions of the Offer</u>."* 

*CVR Agreement. At or prior to the Offer Closing Time, Parent, Merger Sub, the Rights Agent (the "<u>Rights</u> <u>Agent</u>") and the Representative of the holders of the CVRs (the "<u>Representative</u>") will enter into the CVR Agreement governing the terms of certain contingent consideration payable thereunder. Each CVR will represent a contractual right to receive certain contingent cash payments equal to a pro rata share of the following, each pursuant to the CVR Agreement and collectively, "<u>CVR Proceeds</u>":* 

(i) "<u>Disposition Proceeds</u>": 80% of the Net Proceeds (as defined in the CVR Agreement), if any, from any sale, transfer, license or other disposition or grant of rights by Parent or any of its affiliates, including IGM after the Merger, of all or any part of: (a) IGM's product candidates known as: (A) imvotamab, an IgM-based CD20 X CD3 bispecific antibody T cell engager; (B) IGM-2644, an IgM-based CD38 X CD3 bispecific T cell engager; (C) aplitabart (or IGM-8444), a Death Receptor 5 agonist; (D) IGM-7354, a targeted IL-15/IL-15R IgM antibody; (E) IGM-8447, an IgM-based Death Receptor 5 agonist; and (F) IGM-2537, an IgM-based CD123 X CD3 bispecific antibody T cell engager (the "<u>CVR Products</u>"); or (b) patents and patent applications owned or controlled by the Company immediately prior to the closing of the Merger and set forth on Schedule 1 of the CVR Agreement, together with all patents issuing thereon or claiming priority thereto (the "Company Patents"), in each case, that occurs within the period beginning on the Merger Closing Date (as defined in the Merger Agreement) and ending on the first (1<sup>st</sup>) anniversary following the Merger Closing Date, and such Gross Proceeds (as defined in the CVR Agreement) are received by or otherwise due to Parent or any of its Affiliates within one (1) year following the Merger Closing Date; and 

(ii) "<u>Additional Closing Net Cash Proceeds</u>": 100% of the amount by which the Closing Net Cash as finally determined pursuant to the Merger Agreement exceeds $82,000,000, adjusted for any claims that Parent reasonably determines to be valid five (5) business days prior to the Merger Closing Date that are not accounted for in such Closing Net Cash. 

The CVRs are not deferred cash payments to IGM stockholders but instead are contractual rights to receive one or more payments in cash, contingent upon certain events occurring (as described above).

IGM stockholders will be paid promptly in compliance as described in the CVR Agreement. The rights of holders of CVRs will be fixed under the CVR Agreement. The CVRs represent the binding obligations of Parent under the CVR Agreement, and pursuant to Section 10.05 of the Merger Agreement, the holders of CVRs are intended third-party beneficiaries of the rights expressly provided for their benefit in the CVR Agreement.

You should also understand that, as discussed above, the co-offerors estimate that the amount that will be payable under the CVRs is most likely between $0.00–$0.02 per CVR, consisting of: (i) $0.00 per CVR in Disposition Proceeds; and (ii) $0.00–$0.02 per CVR in Additional Closing Net Cash Proceeds. However, this range of values is based on estimates and assumptions regarding future events, as more fully described below, and there is no guarantee

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that any payment will be made to holders of the CVRs, and, thus, for purposes of determining whether to tender your Shares in the Offer you should assume that no payment will be made under the CVR Agreement and the only consideration paid by the co-offerors will be the Cash Amount of $1.247 per Share.

The CVR Agreement provides the holders of CVRs certain contractual rights against Parent, Merger Sub and the Rights Agent. The consent of the holders of at least 40% of the outstanding CVRs (the "<u>Acting</u> <u>Holders</u>") is required any amendments to the CVR Agreement for the purpose of adding, eliminating, or changing provisions therein. The Acting Holders also have the right, on behalf of all holders of CVRs, to institute any action or proceeding at law, in equity, in bankruptcy or otherwise with respect to CVR Agreement, though no individual holder will be entitled to exercise such rights independently. Furthermore, the consent of the Representative is required for Parent or its affiliates to enter into any Disposition Agreement or other agreement providing for a change of control with Parent or its affiliates as the acquiror, licensee or recipient of any CVR Product.

The right to payments under the CVRs as evidenced by the CVR Agreement is a contractual right only and will not be transferable, except in the limited circumstances specified in the CVR Agreement, including: (a) upon death of a Holder by will or intestacy; (b) pursuant to a court order; (c) by operation of law (including by consolidation or merger) or without consideration in connection with the dissolution, liquidation or termination of any corporation, limited liability company, partnership or other entity; (d) in the case of CVRs held in book-entry or other similar nominee form, from a nominee to a beneficial owner and, if applicable, through an intermediary, to the extent allowable by DTC); or (e) that CVRs may be abandoned. The CVRs are not securities, and therefore will not be registered with the SEC.

The foregoing description of the CVR Agreement does not purport to be complete and is qualified in its entirety by reference to the full text of the form of the CVR Agreement, which is filed as Exhibit (d)(4) of the Schedule TO.

*Confidentiality Agreement. IGM and Parent, entered into a confidentiality agreement (the "<u>Confidentiality</u> <u>Agreement</u>") dated May 27, 2025, pursuant to which Parent and its affiliates, including TCM and TCP, agreed, subject to certain exceptions, to keep confidential all proprietary, nonpublic and/or confidential information about the other party, its affiliates or subsidiaries and/or its business furnished in connection with a possible negotiated transaction. Parent's and TCM's obligations under the Confidentiality Agreement will expire three (3) years after the date of the Confidentiality Agreement. The Confidentiality Agreement included customary standstill and fall-away provisions.* 

This summary and description of the material terms of the Confidentiality Agreement does not purport to be complete and is qualified in its entirety by reference to the Confidentiality Agreement, which is filed as Exhibit (d)(2) to the Schedule TO and is incorporated by reference herein.

*Limited Guaranty. Concurrently with the execution of the Merger Agreement, and as a condition and inducement to IGM's willingness to enter into the Merger Agreement, Tang Capital Partners, LP, a Delaware limited partnership ("<u>TCP</u>" or "<u>Guarantor</u>") and sole member of Parent, delivered to IGM a duly executed limited guaranty (the "<u>Limited Guaranty</u>"), dated as of the date of the Merger Agreement, in favor of IGM, in respect of certain obligations of Parent and Merger Sub under the Merger Agreement and the CVR Agreement. Certain obligations under the Limited Guaranty are subject to a cap of $78,000,000, which includes certain Enforcement Costs, under the Merger Agreement and an amount equivalent to the CVR Proceeds (as defined below) under the CVR Agreement.* 

8. **SOURCE AND AMOUNT OF FUNDS.** 

The Offer is not conditioned upon Parent's, Merger Sub's or the Guarantor's ability to finance the purchase of Shares pursuant to the Offer. Parent and Merger Sub estimate that the total amount of funds required to consummate the Merger (including payments for the settlement and cancellation of Company Stock Options and Company Restricted Stock Units) pursuant to the Merger Agreement and to purchase all of the Shares pursuant to the Offer and the Merger Agreement is approximately $78 million, excluding any CVR Proceeds. The funds to pay for all Shares accepted for payment in the Offer may be funded entirely with available cash at Parent. Payments of CVR Proceeds, if any, will be self-funded with: (A) the Net Proceeds from the applicable sale, transfer, license or other disposition or grant of rights by Parent or any of its affiliates, including IGM after the Merger, of all or any part of the CVR Products or the Company Patents that occurs within the period beginning

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on the Merger Closing Date and ending on the first (1<sup>st</sup>) anniversary following the Merger Closing Date, and such Gross Proceeds are received by or otherwise due to Parent or any of its Affiliates by the first (1<sup>st</sup>) anniversary following the Merger Closing Date, if any; and/or (B) with net savings versus the Closing Net Cash that are realized prior to the Merger Closing Date, adjusted for any claims Parent reasonably determines to be valid five (5) business days prior to the Merger Closing Date that are not accounted for in such Closing Net Cash, if any.

In connection with the execution of the Merger Agreement, the Guarantor has agreed to the Limited Guaranty. Subject to the terms of the Limited Guaranty, the Guarantor has agreed to guarantee certain obligations of Parent and Merger Sub up to $78,000,000, which includes certain Enforcement Costs, under the Merger Agreement and up to amount equivalent to the CVR Proceeds under the CVR Agreement. Other than the Limited Guaranty, there are no financing arrangements or alternative financing plans.

We do not believe our financial condition is relevant to your decision whether to tender your Shares and accept the Offer because: (i) the Offer is being made for all outstanding Shares solely for cash and CVRs (which will be self-funded, as described above); (ii) the Offer is not subject to any financing condition; (iii) if we consummate the Offer, we will acquire all remaining Shares for the same price in the Merger; and (iv) the Guarantor has agreed to guarantee the obligations of Parent and Merger Sub under the Merger Agreement, subject to the terms and conditions set forth in the Limited Guaranty.

9. **CONDITIONS OF THE OFFER.** 

Notwithstanding any other term of the Offer or the Merger Agreement, Purchaser shall not be required to accept for payment or, subject to any applicable rules and regulations of the SEC, including Rule 14e-1(c) under the Exchange Act (relating to Purchaser's obligation to pay for or return tendered Shares promptly after the termination or withdrawal of the Offer), to pay for any Shares tendered pursuant to the Offer and, subject to the terms of the Merger Agreement, may delay the acceptance for payment of or payment for Shares or may terminate or amend the Offer, if:

(a) prior to the Expiration Date, there shall not have been validly tendered (and not properly withdrawn) at least one Share more than 50% of the number of voting Shares that are then issued and outstanding as of the expiration of the Offer (the "<u>Minimum Tender Condition</u>"); or 

(b)<br> any of the following conditions exist or shall have occurred and be continuing at the Expiration Date:

(i)<br> there shall be any Legal Restraint (as defined in the Merger Agreement) in effect preventing or prohibiting the consummation of the Offer, the Merger or any of the other transactions contemplated by the Merger Agreement or CVR Agreement;

(ii) (A) (1) any representation or warranty of IGM set forth in Article IV of the Merger Agreement (other than those set forth in Section 4.01 (Organization, Standing and Power) (but only with respect to the first and second sentences thereof), Section 4.02 (Capital Structure), Section 4.04 (Authority; Execution and Delivery; Enforceability), Section 4.05(a)(i) (No Conflicts), Section 4.08(a) (No Material Adverse Effect), Section 4.20 (Brokers and Other Advisors), Section 4.22 (Opinion of Financial Advisors) and Section 4.23 (No Vote Required)) shall not be true and correct as of the Agreement Date and at and as of the Offer Closing Time as if made on and as of the Offer Closing Time, except to the extent such representation or warranty expressly relates to a specified date (in which case on and as of such specified date), other than for such failures to be true and correct that have not had or would not reasonably be expected to have, individually or in the aggregate, a Company Material Adverse Effect (as defined in the Merger Agreement) (for purposes of determining the satisfaction of this condition, without regard to any qualifications or exceptions contained therein as to "materiality" or "Company Material Adverse Effect"), (2) any representation or warranty of IGM set forth in Section 4.01 (Organization, Standing and Power) (but only with respect to the first and second sentences thereof), Section 4.02<u>(a)</u>, <u>(b)</u>, <u>(c)</u>, <u>(d)</u>, <u>(e)</u>, <u>(f)</u> and <u>(g)</u> (Capital Structure), Section 4.04 (Authority; Execution and Delivery; Enforceability), Section 4.05(a)(i) (No Conflicts), Section 4.20 (Brokers and other Advisors), Section 4.22 (Opinion of Financial Advisors), Section 4.23 (No Vote Required), and the Closing Net Cash Schedule shall not be true and correct in all material respects as of the Agreement Date and at and as of the Offer Closing Time as if made on and as of the Offer Closing Time, except to the extent such representation or warranty expressly relates to a specified date (in which case on and as of such 

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specified date), (3) any representation or warranty of IGM set forth in Section 4.02(a) (Capital Structure) of the Merger Agreement shall not be true and correct other than in de minimis respects at and as of such time, except to the extent such representation or warranty expressly relates to a specified date (in which case on and as of such specified date) and (4) any representation or warranty of IGM set forth in Section 4.08(a) (No Material Adverse Effect) of the Merger Agreement shall not be true and correct in all respects as of such time; (B) IGM shall have failed to perform in all material respects the obligations to be performed by it as of such time under the Merger Agreement, including without limitation IGM's obligations under Section 6.02 of the Merger Agreement; (C) Parent shall have failed to receive from IGM a certificate, dated as of the date on which the Offer expires and signed by an executive officer of IGM, certifying to the effect that the Offer Conditions set forth in clauses (A) and (B) have been satisfied as of immediately prior to the expiration of the Offer;

(iii)<br> the Merger Agreement shall have been validly terminated in accordance with its terms (the "<u>Termination Condition</u>"); or

(iv) the Closing Net Cash as finally determined pursuant to <u>Section 2.01(d)</u> of the Merger Agreement is less than $82,000,000 (the "<u>Minimum Cash Condition</u>"). 

The foregoing conditions shall be in addition to, and not a limitation of, the rights of Purchaser to extend, terminate or modify the Offer and are described herein. The foregoing conditions are for the sole benefit of Purchaser and, subject to the terms and conditions of the Merger Agreement and the applicable rules and regulations of the SEC, may be waived by Purchaser in whole or in part at any time and from time to time in its sole discretion. Such rights of termination are described above in "<u>The Tender Offer—Section 7. Summary of</u> <u>the Merger Agreement and Certain Other Agreements—Summary of the Merger Agreement—Termination.</u>" All conditions (including the Minimum Cash Condition), other than the Minimum Tender Condition and the Termination Condition may be waived by Purchaser in its sole discretion in whole or in part at any applicable time or from time to time, in each case subject to the terms and conditions of the Merger Agreement and the applicable rules and regulations of the SEC. The failure by Parent, Merger Sub or any other Affiliate of Parent at any time to exercise any of the foregoing rights shall not be deemed a waiver of any such right, the waiver of any such right with respect to particular facts and circumstances shall not be deemed a waiver with respect to any other facts and circumstances and each such right shall be deemed an ongoing right that may be asserted at any time and from time to time. In accordance with SEC rules and regulations, upon discovery of a condition that gives rise to termination of the Offer, Parent and Merger Sub will undertake to promptly notify IGM stockholders of a decision to either terminate the Offer, or to waive the condition and proceed with the Offer.

10. **DIVIDENDS AND DISTRIBUTIONS.** 

The Merger Agreement provides that IGM will not (subject to certain exceptions), between the date of the Merger Agreement and the Effective Time, declare, set aside or pay any dividends on, or make any other distributions (whether in cash, stock or property) in respect of, any of its capital stock (including the Shares) or other equity interests, except for dividends by a wholly owned subsidiary of IGM to its parent. See "<u>Special</u> <u>Factors—Section 4. Price Range of Shares; Dividends</u>" and "<u>The Tender Offer—Section 7. Summary of the</u> <u>Merger Agreement and Certain Other Agreements—Conduct of Business Pending the Merger</u>."

11. **CERTAIN LEGAL MATTERS; REGULATORY APPROVALS.** 

**General. Except as otherwise set forth in this Offer to Purchase, based on Parent's and Merger Sub's review of publicly available filings by IGM with the SEC and other information regarding IGM, Parent and Merger Sub are not aware of any licenses or other regulatory permits which appear to be material to the business of IGM and which might be adversely affected by the acquisition of Shares by Purchaser pursuant to the Offer or of any approval or other action by any governmental, administrative or regulatory agency or authority which would be required for the acquisition or ownership of Shares by Purchaser pursuant to the Offer. In addition, except as set forth below, Parent and Merger Sub are not aware of any filings, approvals or other actions by or with any governmental body or administrative or regulatory agency that would be required for Purchaser's acquisition or ownership of the Shares. Should any such approval or other action be required, Parent and Merger Sub have agreed to use reasonable best efforts to, in the most expeditious manner practicable, obtain all necessary actions or nonactions, waivers, consents, approvals, orders and authorizations from governmental entities, make all necessary registrations, declarations and filings and make all commercially reasonable efforts to obtain an** 

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approval or waiver from, or to avoid any action by, any governmental entity. The parties currently expect that such approval or action, except as described below under "<u>Takeover Laws</u>," would be sought or taken. There can be no assurance that any such approval or action, if needed, would be obtained or, if obtained, that it will be obtained without substantial conditions; and there can be no assurance that, in the event that such approvals were not obtained or such other actions were not taken, adverse consequences might not result to IGM's or Parent's business or that certain parts of IGM's or Parent's business might not have to be disposed of or held separate. In such an event, we may not be required to purchase any Shares in the Offer. See "<u>The Tender Offer—Section 9.</u> <u>Conditions of the Offer</u>."

**Antitrust. Based on a review of the information currently available relating to the businesses in which Parent and IGM are engaged and the consideration to be paid for the Shares, Parent and Merger Sub have determined that no mandatory antitrust premerger notification filing or waiting period under Hart-Scott Rodino Antitrust Improvements Act of 1976, as amended (the "<u>HSR</u>"), and the rules and regulations promulgated thereunder is required, and therefore HSR clearance is not a condition to the consummation of the Offer or the Merger.** 

Based upon an examination of publicly available and other information relating to the businesses in which IGM is engaged, Parent and Merger Sub believe that the acquisition of Shares in the Offer (and the Merger) should not violate applicable antitrust laws. Nevertheless, Parent and Merger Sub cannot be certain that a challenge to the Offer (and the Merger) on antitrust grounds will not be made, or, if such challenge is made, what the result will be. See "<u>The Tender Offer—Section 9. Conditions of the Offer</u>."

**Stockholder Approval Not Required. Assuming the Offer and the Merger are consummated in accordance with Section 251(h) of the DGCL, IGM has represented in the Merger Agreement that execution, delivery and performance of the Merger Agreement by IGM and the consummation by IGM of the Offer and the Merger have been duly validly authorized by all necessary corporate action on the part of IGM, and no other corporate proceedings on the part of IGM are necessary to authorize the Merger Agreement or to consummate the Offer and the Merger. Section 251(h) of the DGCL provides that stockholder approval of a merger is not required if certain requirements are met, including that: (i) the acquiring company consummates an offer for all of the outstanding stock of the company to be acquired that, absent Section 251(h) of the DGCL, would be entitled to vote on such merger; (ii) following the consummation of such tender offer, the stock irrevocably accepted for purchase pursuant to the offer, together with the stock otherwise owned by the consummating company and its affiliates and any "rollover stock" (as defined in Section 251(h) of the DGCL), equals at least such percentage of the stock of the company to be acquired that, absent Section 251(h) of the DGCL, would be required to adopt the merger agreement; and (iii) the stockholders at the time of the merger receive the same consideration for their stock in the merger as was payable in the tender offer. If the Minimum Tender Condition is satisfied and we accept Shares for payment pursuant to the Offer, we will hold a sufficient number of Shares to ensure that IGM will not be required to submit the adoption of the Merger Agreement to a vote of its stockholders. Following the consummation of the Offer and subject to the satisfaction of the remaining conditions set forth in the Merger Agreement, Merger Sub, Parent and IGM will take all necessary and appropriate action to effect the Merger as promptly as practicable without a meeting of stockholders of IGM in accordance with Section 251(h) the DGCL. See "<u>Special Factors—Section 2. Purpose of the Offer and Plans for IGM</u>" and "<u>The Tender Offer—Section 7.</u> <u>Summary of the Merger Agreement and Certain Other Agreements</u>."** 

**Takeover Laws. A number of states (including Delaware, where IGM is incorporated) have adopted takeover laws and regulations which purport, to varying degrees, to be applicable to attempts to acquire securities of corporations which are incorporated in such states or which have substantial assets, stockholders, principal executive offices or principal places of business therein.** 

As a Delaware corporation, IGM has not opted out of Section 203 of the DGCL. In general, Section 203 of the DGCL would prevent an "interested stockholder" (generally defined in Section 203 of the DGCL as a person beneficially owning 15% or more of a corporation's voting stock and the affiliates and associates of such person) from engaging in a "business combination" (as defined in Section 203 of the DGCL) with a Delaware corporation for three years following the time such person became an interested stockholder unless, among other exceptions: (i) before such person became an interested stockholder, the board of directors of the corporation approved the transaction in which the interested stockholder became an interested stockholder or approved the business combination; (ii) upon consummation of the transaction which resulted in the interested stockholder becoming an interested stockholder, the interested stockholder owned at least 85% of the voting stock of the

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corporation outstanding at the time the transaction commenced (excluding for purposes of determining the number of shares of outstanding stock held by directors who are also officers and by employee stock plans that do not allow plan participants to determine confidentially whether to tender shares); or (iii) following the transaction in which such person became an interested stockholder, the business combination is: (A) approved by the board of directors of the corporation; and (B) authorized at a meeting of stockholders by the affirmative vote of the holders of at least 66 2/3% of the outstanding voting stock of the corporation not owned by the interested stockholder. The restrictions on business combinations contained in Section 203 of the DGCL also do not apply, among other possibilities, (i) to corporations that do not have a class of voting stock listed on a national securities exchange or held of record by more than 2,000 stockholders (unless the corporation's certificate of incorporation expressly provides otherwise) or (ii) to interested stockholders who became interested stockholders at a time when the restrictions on business combinations did not apply because of the foregoing clause (i).

IGM has represented to us in the Merger Agreement, assuming certain of our representations as to our stock ownership in IGM are true, that the IGM Board has taken all actions so that the restrictions applicable to business combinations contained in Section 203 of the DGCL are not, and will not be, applicable to the execution, delivery or performance of the Merger Agreement and the timely consummation of the Offer and the Merger and will not restrict, impair or delay the ability of Parent or Merger Sub, after the Offer Closing Time, to vote or otherwise exercise all rights as a stockholder of IGM. Purchaser has not attempted to comply with any other state takeover statutes in connection with the Offer or the Merger. Purchaser reserves the right to challenge the validity or applicability of any state law allegedly applicable to the Offer, the Merger or the Merger Agreement, and nothing in this Offer to Purchase or any action taken in connection herewith is intended as a waiver of that right. In the event that it is asserted that one or more takeover statutes apply to the Offer, the Merger or the Merger Agreement, and it is not determined by an appropriate court that such statute or statutes do not apply or are invalid as applied to the Offer, the Merger or the Merger Agreement, as applicable, Purchaser may be required to file certain documents with, or receive approvals from, the relevant state authorities, and Purchaser might be unable to accept for payment or purchase Shares tendered pursuant to the Offer or be delayed in continuing or consummating the Offer. In such case, Purchaser may not be obligated to accept for purchase, or pay for, any Shares tendered. See "<u>The Tender Offer—Section 9. Conditions of</u> <u>the Offer</u>."

**Appraisal Rights. No appraisal rights are available to the holders of record or beneficial owners of Shares in connection with the Offer. However, if the Offer is successful and the Merger is consummated, stockholders of record or beneficial owners of Shares who: (i) did not tender their Shares in the Offer (or who had tendered but subsequently validly withdrawn such tender, and not otherwise waived their appraisal rights); (ii) otherwise comply with the applicable requirements and procedures of Section 262 of the DGCL; and (iii) do not thereafter withdraw their demand for appraisal of such Shares or otherwise lose their appraisal rights, in each case in accordance with the DGCL, will be entitled to demand appraisal of their Shares and receive in lieu of the consideration payable in the Merger a cash payment equal to the "fair value" of their Shares, as determined by the Delaware Court of Chancery, in accordance with Section 262 of the DGCL. If you choose to exercise your appraisal rights in connection with the Merger and you properly demand and perfect such rights in accordance with Section 262 of the DGCL, you may be entitled to payment for your Shares based on a judicial determination of the fair value of your Shares plus interest, if any, on the amount determined to be fair value.** 

The following discussion is not a complete statement of the law pertaining to appraisal rights under the DGCL and is qualified in its entirety by the full text of Section 262 of the DGCL, a copy of which may be accessed without subscription or cost at the following publicly available website: https://delcode.delaware.gov/title8/c001/sc09/index.html#262. All references in Section 262 of the DGCL and in this summary to a (i) "stockholder" are to the record holder of Shares unless otherwise expressly noted herein, (ii) "beneficial owner" are to a person who is the beneficial owner of Shares held either in voting trust or by a nominee on behalf of such person, and (iii) "person" are to an individual, corporation, partnership, unincorporated association or other entity. Stockholders and beneficial owners of Shares should carefully review the full text of Section 262 of the DGCL as well as the information discussed herein. Stockholders and beneficial owners of Shares should assume that IGM will take no action to perfect any appraisal rights of any person.

The "fair value" of the Shares as determined by the Delaware Court of Chancery could be based upon considerations other than, or in addition to, the price paid in the Offer and the Merger and the market value of such Shares. Stockholders and beneficial owners of Shares should recognize that the fair value determined in an appraisal proceeding of the Delaware Court of Chancery could be higher or lower than, or the same as, the Offer

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Price and that an investment banking opinion as to the fairness, from a financial point of view, of the consideration payable in a sale transaction, such as the Offer and the Merger, is not an opinion as to, and does not otherwise address, fair value under the DGCL. Moreover, Parent and IGM may argue in an appraisal proceeding that, for purposes of such proceeding, the "fair value" of such Shares is less than the Offer Price.

**Any person who desires to exercise his, her or its appraisal rights should review carefully Section 262 of the DGCL and is urged to consult his, her or its legal advisor before electing or attempting to exercise such rights.** 

Under Section 262 of the DGCL, if a merger is approved under Section 251(h) of the DGCL, either a constituent corporation before the effective date of the merger, or the surviving corporation within 10 days thereafter, must notify each of the holders of any class or series of stock of such constituent corporation who are entitled to appraisal rights of the approval of the merger and that appraisal rights are available for any or all shares of such class or series of stock of such constituent corporation, and shall include in such notice either a copy of Section 262 of the DGCL or information directing the stockholders to a publicly available electronic resource at which Section 262 of the DGCL may be accessed without subscription or cost. **THE SCHEDULE 14D-9 CONSTITUTES THE FORMAL NOTICE OF APPRAISAL RIGHTS UNDER SECTION 262 OF THE DGCL. FAILURE TO FOLLOW THE STEPS REQUIRED BY SECTION 262 OF THE DGCL FOR EXERCISING AND PERFECTING APPRAISAL RIGHTS WILL RESULT IN THE LOSS OF SUCH RIGHTS.**

As discussed in the Schedule 14D-9, stockholders and beneficial owners of Shares wishing to exercise the right to seek an appraisal of their Shares under Section 262 of the DGCL must do ALL of the following:

&nbsp;&nbsp;&nbsp;&nbsp;• within the later of the consummation of the Offer (which will occur at the date and time of the acceptance for payment of Shares pursuant to and subject to the conditions of the Offer) and 20 days after the sending of the Schedule 14D-9, deliver to IGM at the address indicated in the Schedule 14D-9 a written demand for appraisal of their Shares, which demand must reasonably inform IGM of the identity of the person making the demand and that the person is demanding appraisal and, in the case of a demand made by a beneficial owner of Shares, must also reasonably identify the holder of record of the Shares for which the demand is made, be accompanied by documentary evidence of such beneficial owner's beneficial ownership of stock and a statement that such documentary evidence is a true and correct copy of what it purports to be, and provide an address at which such beneficial owner consents to receive notices given by the surviving corporation and to be set forth on the verified list required by subsection (f) of Section 262 of the DGCL;

&nbsp;&nbsp;&nbsp;&nbsp;• not tender his, her or its Shares pursuant to the Offer (or, if tendered, validly and subsequently withdraw such Shares prior to the time Parent accepts properly tendered Shares for purchase); and

&nbsp;&nbsp;&nbsp;&nbsp;• continuously hold of record or beneficially own, as applicable, the Shares from the date on which the written demand for appraisal is made through the Effective Time.

Any person who sells Shares in the Offer will not be entitled to exercise appraisal rights with respect thereto but rather will receive the Offer Price, subject to the terms and conditions of the Merger Agreement, as well as the Offer to Purchase and related Letter of Transmittal, as applicable.

The preservation and exercise of appraisal rights require strict and timely adherence to the applicable provisions of Delaware law which will be set forth in detail in the Schedule 14D-9.

The information provided above is for informational purposes only with respect to your alternatives if the Merger is consummated. Any person who desires to exercise his, her or its appraisal rights should review carefully Section 262 of the DGCL and is urged to consult his, her or its legal advisor before electing or attempting to exercise such rights. The foregoing summary does not constitute any legal or other advice nor does it constitute a recommendation that IGM stockholders or beneficial owners of Shares exercise appraisal rights under Section 262 of the DGCL.

If you tender your Shares into the Offer, you will not be entitled to exercise appraisal rights with respect to your Shares but, instead, subject to the conditions to the Offer, you will receive the Offer Price for your Shares.

"**Going Private" Transactions**. Rule 13e-3 under the Exchange Act is applicable to certain "going private" transactions and may under certain circumstances be applicable to the Merger. However, Rule 13e-3 will be

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inapplicable if: (i) the Shares are deregistered under the Exchange Act prior to the Merger or another business combination; or (ii) the Merger or other business combination is consummated within one year after the purchase of the Shares pursuant to the Offer and the amount paid per Share in the Merger or other business combination is at least equal to the amount paid per Share in the Offer. Neither Parent nor Merger Sub believes that Rule 13e-3 will be applicable to the Merger.

**Litigation. There have been no lawsuits filed against IGM, the IGM Board, Parent or Merger Sub in connection with the Offer. Lawsuits may be filed against IGM and the IGM Board, and lawsuits may be filed against Parent and Merger Sub, in connection with the Offer, the Merger and the related disclosures. Absent new or different allegations that are material, Parent and Merger Sub will not, and understand that IGM will not, necessarily announce such filings.** 

12. **FEES AND EXPENSES.** 

Parent has retained the Depositary and Paying Agent and the Information Agent in connection with the Offer. The Depositary and Paying Agent and the Information Agent will receive customary compensation, reimbursement for reasonable out-of-pocket expenses and indemnification against certain liabilities in connection with the Offer, including certain liabilities under the federal securities laws.

As part of the services included in such retention, the Information Agent may contact holders of Shares by personal interview, mail, electronic mail, telephone, telex, telegraph and other methods of electronic communication and may request brokers, dealers, commercial banks, trust companies and other nominees to forward the Offer materials to beneficial holders of Shares.

Except as set forth above, neither Parent nor Merger Sub will pay any fees or commissions to any broker or dealer or other person for soliciting tenders of Shares pursuant to the Offer. Brokers, dealers, commercial banks and trust companies will upon request be reimbursed by us for customary mailing and handling expenses incurred by them in forwarding the offering material to their customers.

13. **MISCELLANEOUS.** 

The Offer is being made to all holders of the Shares. We are not aware of any jurisdiction in which the making of the Offer or the acceptance thereof would be prohibited by securities, "blue sky" or other valid laws of such jurisdiction. If we become aware of any U.S. state in which the making of the Offer or the acceptance of Shares pursuant thereto would not be in compliance with an administrative or judicial action taken pursuant to a U.S. state statute, we will make a good faith effort to comply with any such law. If, after such good faith effort, we cannot comply with any such law, the Offer will not be made to (nor will tenders be accepted from or on behalf of) the holders of Shares in such state. In any jurisdictions where applicable laws require the Offer to be made by a licensed broker or dealer, the Offer shall be deemed to be made on behalf of Purchaser by one or more registered brokers or dealers licensed under the laws of such jurisdiction to be designated by Purchaser.

Parent and Merger Sub have filed with the SEC the Schedule TO (including exhibits) in accordance with the Exchange Act, furnishing certain additional information with respect to the Offer, and may file amendments thereto. The Schedule TO and any amendments thereto, including exhibits, may be examined and copies may be obtained from the SEC in the manner set forth in "<u>The Tender Offer—Section 5. Certain Information Concerning</u> <u>IGM</u>."

The Offer does not constitute a solicitation of proxies for any meeting of IGM stockholders. Any solicitation of proxies which Purchaser or any of its affiliates might seek would be made only pursuant to separate proxy materials complying with the requirements of Section 14(a) of the Exchange Act.

No person has been authorized to give any information or make any representation on behalf of Parent or Merger Sub not contained in this Offer to Purchase or in the Letter of Transmittal and, if given or made, such information or representation must not be relied upon as having been authorized. No broker, dealer, bank, trust company, fiduciary or other person shall be deemed to be an agent of Parent, Merger Sub, the Depositary and Paying Agent or the Information Agent for the purpose of the Offer. Neither delivery of this Offer to Purchase nor any purchase pursuant to the Offer will, under any circumstances, create any implication that there has been no change in the affairs of Parent, Merger Sub, IGM or any of their respective subsidiaries since the date as of which information is furnished or the date of this Offer to Purchase.

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| |
|:---|
| Concentra Biosciences, LLC |
| Concentra Merger Sub V, Inc.  |
| Tang Capital Partners, LP  |
| Tang Capital Management, LLC |
| July 16, 2025 |

---

#### SCHEDULE A <br>

#### INFORMATION CONCERNING MEMBERS OF THE BOARDS OF DIRECTORS AND <br>

#### THE EXECUTIVE OFFICERS OF PARENT, MERGER SUB AND THE GUARANTOR.
1. **Concentra Biosciences, LLC** 

Concentra Biosciences, LLC's principal business is currently to consummate the Offer and effect the Merger pursuant to the Merger Agreement, and to perform its obligations under the CVR Agreement following the Merger when IGM is a wholly owned subsidiary of Parent as the surviving entity from the Merger. The following table sets forth information about the executive officers of Concentra Biosciences, LLC as of July 15, 2025.

---

| | |
|:---|:---|
| **Name, Position** <br>**Country of Citizenship** | **Present Principal Occupation or Employment; Material Positions** <br>**Held During the Past Five Years; Certain Other Information**  |
| Kevin Tang, <br>Chairman and Chief Executive <br>Officer Citizenship: United States | Mr. Tang is the Chief Executive Officer of Concentra Biosciences, LLC and Chief Executive Officer and Chairman of Concentra Merger Sub V, Inc. He is also the President of Tang Capital Management, LLC, a life sciences-focused investment company he founded in 2002. Since 2024, Mr. Tang has served as Chair of the Board of Aurinia Pharmaceuticals Inc. From 2014 through its acquisition by Innoviva, Inc. in 2022, he was Chairman of La Jolla Pharmaceutical Company. In 2013, Mr. Tang founded Odonate Therapeutics, Inc. and served as its Chairman and Chief Executive Officer through 2022. He co-founded Heron Therapeutics, Inc. in 2009 and served as Director from 2009 to 2012 and Chairman from 2012 to 2020. From 2009 through its acquisition by Endo Pharmaceuticals, Inc. in 2010, Mr. Tang was a director of Penwest Pharmaceuticals Co. In 2006, he co-founded Ardea Biosciences, Inc. and served as a director through its acquisition by AstraZeneca PLC in 2012. From 2001 to 2008, Mr. Tang served as a director of Trimeris, Inc. From 1993 to 2001, he was a research analyst at Deutsche Banc Alex Brown, Inc., an investment banking firm, and most recently was a Managing Director and head of the firm's Life Sciences research group. Mr. Tang received a B.S. degree from Duke University.  |
| Michael Hearne, <br>Chief Financial Officer <br>Citizenship: United States | Mr. Hearne is the Chief Financial Officer of Concentra Biosciences, LLC and Chief Financial Officer of Concentra Merger Sub V, Inc. Since 2015, he has served as Chief Financial Officer of Tang Capital Management, LLC, a life sciences-focused investment company. From 2020 to 2022, Mr. Hearne served as Chief Financial Officer of La Jolla Pharmaceutical Company. From 2015 to 2022, he held various positions at Odonate Therapeutics, Inc., most recently serving as Chief Financial Officer. From 2014 to 2015, Mr. Hearne served as a partner at Weaver & Tidwell, LLP. He started his career in public accounting at Coopers & Lybrand. Mr. Hearne received a B.S. degree in accounting and a masters of accountancy, taxation from Brigham  |

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#### **TABLE OF CONTENTS**

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| | |
|:---|:---|
| **Name, Position** <br>**Country of Citizenship** | **Present Principal Occupation or Employment; Material Positions** <br>**Held During the Past Five Years; Certain Other Information**  |
|  | Young University and is a Certified Public Accountant (inactive) in the state of California.  |
| Ryan Cole, <br>Chief Operating Officer <br>Citizenship: United States | Mr. Cole is the Chief Operating Officer of Concentra Biosciences, LLC and Chief Operating Officer of Concentra Merger Sub V, Inc. Since 2014, he has served in various positions at Tang Capital Management, LLC, a life sciences-focused investment company, most recently serving as Chief Operating Officer since 2022. From 2012 to 2014, Mr. Cole served as a Senior Financial Analyst of Mergers and Acquisitions at Thermo Fisher Scientific Inc. He started his career in public accounting at Ernst & Young, LLP. Mr. Cole received a B.A. degree in accounting and finance from Santa Clara University and is a Certified Public Accountant (inactive) in the state of California.  |
| Stew Kroll, <br>Chief Development Officer <br>Citizenship: United States | Mr. Kroll is the Chief Development Officer of Concentra Biosciences, LLC and Chief Development Officer of Concentra Merger Sub V, Inc. Since 2016, he has served in various positions at Tang Capital Management, LLC, a life sciences-focused investment company, most recently serving as Managing Director since 2021. From 2017 through its acquisition by Innoviva, Inc. in 2022, Mr. Kroll served as Chief Development Officer of La Jolla Pharmaceutical Company. From 2016 to 2021, he held various positions at Odonate Therapeutics, Inc., most recently serving as Chief Development Officer. From 2005 to 2016, Mr. Kroll held various positions at Threshold Pharmaceuticals, Inc., most recently serving as Chief Operating Officer. From 2000 to 2005, he served as Senior Director of Biostatistics at Corixa Corporation. From 1997 to 2000, Mr. Kroll held various positions at Coulter Pharmaceutical, Inc., most recently serving as Director of Biostatistics. He received an M.A. degree and B.A. degree in statistics from the University of California, Berkeley.  |
| Thomas Wei, <br>Chief Business Officer <br>Citizenship: United States | Mr. Wei is the Chief Business Officer of Concentra Biosciences, LLC and Chief Business Officer of Concentra Merger Sub V, Inc. Since 2015, he has served as Managing Director of Tang Capital Management, LLC, a life sciences-focused investment company. From 2015 to 2021, Mr. Wei held various positions at Odonate Therapeutics, Inc., most recently serving as Chief Scientific Officer. From 2009 to 2015, he served as a Managing Director and biotechnology equity research analyst at Jefferies LLC. From 2003 to 2009, Mr. Wei was a biotechnology equity research analyst at Piper Jaffray, most recently serving as Managing Director. From 1998 to 2003, he was a biotechnology equity research analyst at Deutsche Bank AG and Adams, Harkness & Hill Inc. Mr. Wei received an A.B. degree in biochemical sciences from Harvard University and an M.B.A. degree from Oxford University. |

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The common business address and telephone number for the sole director and executive officers of Purchaser is as follows: c/o Concentra Biosciences, LLC, Inc., 4747 Executive Drive, Suite 210, San Diego, California 92121, Tel. (858) 281-5372.

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2. **Concentra Merger Sub V, Inc.** 

Concentra Merger Sub V, Inc. was incorporated for the purpose of consummating and effecting the Merger pursuant to the Merger Agreement. The following table sets forth information about the sole director and executive officers of Concentra Merger Sub V, Inc. as of July 15, 2025.

---

| | |
|:---|:---|
| **Name, Position** <br>**Country of Citizenship** | **Present Principal Occupation or Employment;** <br>**Material Positions Held During the Past Five Years**  |
| Kevin Tang, Chief Executive Officer <br>Citizenship: United States | Refer above.  |
| Michael Hearne, Chief Financial Officer <br>Citizenship: United States | Refer above.  |
| Ryan Cole, Chief Operating Officer <br>Citizenship: United States | Refer above.  |
| Stew Kroll, Chief Development Officer <br>Citizenship: United States | Refer above.  |
| Thomas Wei, Chief Business Officer <br>Citizenship: United States | Refer above. |

---

The common business address and telephone number for all the directors and executive officers of Merger Sub is as follows: c/o Concentra Merger Sub V, 4747 Executive Drive, Suite 210, San Diego, California 92121, Tel: (858) 281-5372.

3. **Tang Capital Management, LLC** 

Tang Capital Management, LLC is the sole manager of Parent and general partner of TCP. The following table sets forth information about the executive officers of Tang Capital Management, LLC as of July 15, 2025.

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| | |
|:---|:---|
| **Name, Position Country of Citizenship** | **Present Principal Occupation or Employment;** <br>**Material Positions Held During the Past Five Years**  |
| Kevin Tang, President <br>Citizenship: United States | Refer above.  |
| Michael Hearne, Chief Financial Officer <br>Citizenship: United States | Refer above.  |
| Ryan Cole, Chief Operating Officer <br>Citizenship: United States | Refer above. |

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The common business address and telephone number for TCM, Mr. Tang, Mr. Hearne and Mr. Cole is as follows: c/o Tang Capital Management, LLC, 4747 Executive Drive, Suite 210, San Diego, California 92121, Tel. (858) 200-3830.

4. **Tang Capital Partners, LP** 

Tang Capital Partners, LP's principal business is a life sciences-focused investment company. Tang Capital Management, LLC is the general partner of Tang Capital Partners, LP. The business address and telephone number for TCP is as follows: c/o Tang Capital Management, LLC, 4747 Executive Drive, Suite 210, San Diego, California 92121, Tel. (858) 200-3830.

The Letter of Transmittal, certificates (if any) for Shares and any other required documents should be sent by each stockholder of IGM to the Depositary and Paying Agent as follows:

*The Depositary and Paying Agent for the Offer is:* 

Broadridge Corporate Issuer Solutions, LLC

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Mail or deliver the Letter of Transmittal, together with the certificate(s) (if any) representing your shares, to:

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| | |
|:---|:---|
| *If delivering by mail:* | *If delivering by express mail, courier,* <br>*or other expedited service:*  |
| Broadridge, Inc.<br>Attention: BCIS Re-Organization Dept.<br>P.O. Box 1317<br>Brentwood, NY 11717-0718 | Broadridge, Inc. <br>Attention: BCIS IWS<br>51 Mercedes Way<br>Edgewood, NY 11717 |

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#### Other Information:
Questions or requests for assistance or additional copies of this Offer to Purchase, the Letter of Transmittal, and the Schedule TO may be directed to the Information Agent at its location and telephone numbers set forth below. Stockholders may also contact their broker, dealer, commercial bank or trust company for assistance concerning the Offer.

*The Information Agent for the Offer is:*![](logo_mackenzie4.jpg)<br>

7 Penn Plaza<br>

New York, New York 10001<br>

(212) 929-5500

You may call MacKenzie Partners, Inc., the Information Agent for the Offer, toll-free at (800) 322-2885 or email them at tenderoffer@mackenziepartners.com.

55<br>

## Ex-99.(A)(1)(B)

#### Exhibit (a)(1)(B)
[This space is intentionally left blank and reserved for registered shareholder detail]

#### Letter of Transmittal<br>

#### To Tender Shares of Common Stock<br>

#### of<br>

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>

### IGM BIOSCIENCES, INC. <br>

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>

#### at <br>
**A Cash Amount of $1.247 per Share, Plus One Non-Transferable Contractual Contingent Value Right for Each Share ("<u>CVR</u>"), Which Represents the Right to Receive One or More Potential Cash Payments, Contingent upon: (i) the Receipt of Proceeds from Any CVR Product or Company Patent Disposition that Occurs Within One (1) Year Following the Merger Closing Date and Such Proceeds Are Received by or Otherwise Due to Parent or Any of Its Affiliates by the First (1st) Anniversary Following the Merger Closing Date; and (ii) Closing Net Cash in Excess of $82,000,000, As Determined Five (5) Business Days Prior to the Merger Closing Date, as Described in the CVR Agreement.**

<br> #### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>

#### Pursuant to the Offer to Purchase <br>

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>

#### Dated July 16, 2025 <br>

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>

#### by <br>

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>

#### CONCENTRA BIOSCIENCES, LLC <br>

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>

#### CONCENTRA MERGER SUB V, INC., <br>

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>

#### a wholly owned subsidiary of Purchaser<br>

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>

#### TANG CAPITAL PARTNERS, LP <br>

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>

#### TANG CAPITAL MANAGEMENT, LLC <br>

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>

#### THE OFFER AND WITHDRAWAL RIGHTS WILL EXPIRE ONE MINUTE AFTER<br>

#### 11:59 P.M. EASTERN TIME ON AUGUST 13, 2025 (THE " EXPIRATION DATE "),<br>

#### UNLESS THE OFFER IS EXTENDED OR EARLIER TERMINATED.
*The Depositary and Paying Agent for the Offer Is:*

Broadridge Corporate Issuer Solutions, LLC

#### Mail or deliver the Letter of Transmittal, together with the certificate(s) (if any) representing your shares, to :

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| | |
|:---|:---|
| *If delivering by hand, express mail, courier* <br>*or other expedited service:* | *If delivering by mail:*  |
| Broadridge, Inc. <br>Attention: BCIS IWS <br>51 Mercedes Way <br>Edgewood, NY 11717 | Broadridge, Inc. <br>Attention: BCIS Re-Organization Dept. <br>P.O. Box 1317 <br>Brentwood, NY 11717-0718 |

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Ladies and Gentlemen:

The undersigned hereby tenders to Concentra Biosciences, LLC, a Delaware limited liability company ("<u>Parent</u>" or "<u>Purchaser</u>"), the above described shares of common stock, par value $0.01 per share (the "<u>Shares</u>"), of IGM Biosciences, Inc., a Delaware corporation ("<u>IGM</u>"), pursuant to Purchaser's offer to purchase each outstanding Share that is validly tendered and not properly withdrawn, for: (i) $1.247 per Share in cash (the "<u>Cash Amount</u>"); and (ii) one non-transferable contractual contingent value right for each Share (each, a "<u>CVR,</u>" and each CVR together with the Cash Amount, the "<u>Offer Price</u>"), subject to the terms and conditions described in the Offer to Purchase, dated July 16, 2025 (together with any amendments or supplements thereto, the "<u>Offer to Purchase</u>") and in this Letter of Transmittal (together with any amendments or supplements thereto, the "<u>Letter of Transmittal</u>" which, together with the Offer to Purchase, as each may be amended and supplemented from time to time, collectively constitute the "<u>Offer</u>"), receipt of which is hereby acknowledged.

Upon the terms and subject to the conditions of the Offer (and if the Offer is extended or amended, the terms of any such extension or amendment), and effective upon acceptance for payment of the Shares validly tendered herewith and not properly withdrawn on or prior to the Expiration Date in accordance with the terms of the Offer, the undersigned hereby sells, assigns and transfers to or upon the order of Purchaser all right, title and interest in and to all of the Shares that are being tendered hereby (and any and all dividends, distributions, rights, other Shares or other securities issued or issuable in respect thereof on or after the date hereof (collectively, "<u>Distributions</u>")) and irrevocably constitutes and appoints Broadridge Corporate Issuer Solutions, LLC (the "<u>Depositary and Paying Agent</u>") the true and lawful agent and attorney-in-fact of the undersigned with respect to such Shares (and any and all Distributions), with full power of substitution (such power of attorney being deemed to be an irrevocable power coupled with an interest in the Shares tendered by this Letter of Transmittal), to: (i) deliver Certificates for such Shares (and any and all Distributions) or transfer ownership of such Shares (and any and all Distributions) on the account books maintained by The Depository Trust Company ("<u>DTC</u>") or otherwise held in book-entry form, together, in any such case, with all accompanying evidences of transfer and authenticity, to or upon the order of Purchaser; (ii) present such Shares (and any and all Distributions) for transfer on the books of IGM; and (iii) receive all benefits and otherwise exercise all rights of beneficial ownership of such Shares (and any and all Distributions), all in accordance with the terms and subject to the conditions of the Offer.

By executing this Letter of Transmittal, the undersigned hereby irrevocably appoints Kevin Tang, the designee of Purchaser, the attorney-in-fact and proxy of the undersigned, with full power of substitution, to: (i) vote at any annual or special meeting of IGM stockholders or any adjournment or postponement thereof or otherwise in such manner as such attorney-in-fact and proxy or his substitute shall in his, her or its sole discretion deem proper with respect to; (ii) execute any written consent concerning any matter as such attorney-in-fact and proxy or his substitute shall in his, her or its sole discretion deem proper with respect to; and (iii) otherwise act as such attorney-in-fact and proxy or his substitute shall in his, her or its sole discretion deem proper with respect to, all of the Shares (and any and all Distributions) tendered hereby and accepted for payment by Purchaser. This appointment will be effective if and when, and only to the extent that, Purchaser accepts such Shares tendered with this Letter of Transmittal for payment pursuant to the Offer. This power of attorney and proxy are irrevocable and are granted in consideration of the acceptance for payment of such Shares in accordance with the terms of the Offer. Such acceptance for payment shall, without further action, revoke any prior powers of attorney and proxies granted by the undersigned at any time with respect to such Shares (and any and all Distributions), and no subsequent powers of attorney, proxies, consents or revocations may be given by the undersigned with respect thereto (and, if given, will not be deemed effective). Purchaser reserves the right to require that, in order for the Shares to be deemed validly tendered, immediately upon Purchaser's acceptance for payment of such Shares, Purchaser or its designees must be able to exercise full voting, consent and other rights with respect to such Shares (and any and all Distributions), including voting at any meeting of IGM stockholders or executing a written consent concerning any matter.

The undersigned hereby represents and warrants that the undersigned has full power and authority to tender, sell, assign and transfer any and all of the Shares tendered hereby (and any and all Distributions) and that, when the same are accepted for payment by Purchaser, Purchaser will acquire good, marketable and unencumbered title to such Shares (and such Distributions), free and clear of all liens, restrictions, charges and encumbrances and the same will not be subject to any adverse claims. The undersigned hereby represents and warrants that the undersigned is the registered owner of the Shares. The undersigned will, upon request, execute and deliver any

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additional documents deemed by the Depositary and Paying Agent or Purchaser to be necessary or desirable to complete the sale, assignment and transfer of the Shares tendered hereby (and any and all Distributions). In addition, the undersigned shall remit and transfer promptly to the Depositary and Paying Agent for the account of Purchaser all Distributions in respect of any and all of the Shares tendered hereby, and, pending such remittance and transfer or appropriate assurance thereof, Purchaser shall be entitled to all rights and privileges as owner of each such Distribution and may withhold the entire Offer Price of the Shares tendered hereby or deduct from such Offer Price the amount or value of such Distribution as determined by Purchaser in its sole discretion.

All authority conferred or agreed to be conferred pursuant to this Letter of Transmittal shall not be affected by, and shall survive the death or incapacity of the undersigned, and any obligation of the undersigned hereunder shall be binding upon the heirs, executors, administrators, personal representatives, trustees in bankruptcy, successors and assigns of the undersigned. Except as stated in the Offer to Purchase, this tender is irrevocable.

It is understood that the undersigned will not receive payment for the Shares unless and until the Shares are accepted for payment and until the Certificate(s) owned by the undersigned are received by the Depositary and Paying Agent at the address set forth above, together with such additional documents as the Depositary and Paying Agent may require, and until the same are processed for payment by the Depositary and Paying Agent.

**The undersigned hereby acknowledges that delivery of any Certificate shall be effected, and risk of loss and title to such Certificate shall pass, only upon the proper delivery of such Certificate to the Depositary and Paying Agent.** 

The undersigned understands that the valid tender of Shares pursuant to any of the procedures described in the Offer to Purchase and in the instructions hereto will constitute the undersigned's acceptance of the terms and conditions of the Offer. Purchaser's acceptance of such Shares for payment will constitute a binding agreement between the undersigned and Purchaser upon the terms and subject to the conditions of the Offer (and if the Offer is extended or amended, the terms and conditions of such extension or amendment). The undersigned recognizes that under certain circumstances set forth in the Offer, Purchaser may not be required to accept for payment any Shares tendered hereby.

The undersigned understands that the CVRs will not be transferable except: (a) upon death of the holder by will or intestacy; (b) pursuant to a court order; (c) by operation of law (including by consolidation or merger) or without consideration in connection with the dissolution, liquidation or termination of any corporation, limited liability company, partnership or other entity; (d) in the case of CVRs held in book-entry or other similar nominee form, from a nominee to a beneficial owner and, if applicable, through an intermediary, to the extent allowable by the Depository Trust Company ("<u>DTC</u>")); or (e) that CVRs may be abandoned by transferring such CVR to Purchaser without consideration therefor. The undersigned further understands that the CVRs will not have any voting or dividend rights, or accrue interest and will not represent any equity or ownership interests in the Purchaser or IGM. The undersigned understands that the CVRs will be registered in the name of the undersigned.

Unless otherwise indicated under "Special Payment Instructions," a check will be issued for the Cash Amount of all Shares purchased and, if appropriate, Certificates not tendered or accepted for payment in the name(s) of the registered holder(s) appearing above under "Description of Shares Tendered" will be returned. Similarly, unless otherwise indicated under "Special Delivery Instructions," the check for the Cash Amount of all Shares purchased will be mailed and, if appropriate, any Certificates not tendered or not accepted for payment (and any accompanying documents, as appropriate) will be returned to the address(es) of the registered holder(s) appearing above under "Description of Shares Tendered." In the event that the boxes entitled "Special Payment Instructions" and "Special Delivery Instructions" are both completed, the check for the Cash Amount of all Shares purchased will be issued and, if appropriate, any Certificates not tendered or not accepted for payment (and any accompanying documents, as appropriate) will be returned in the name(s) of, and deliver such check and, if appropriate, return any Certificates (and any accompanying documents, as appropriate) to, the person(s) so indicated. The undersigned recognizes that Purchaser has no obligation, pursuant to the "Special Payment Instructions," to transfer any Shares from the name of the registered holder thereof if Purchaser does not accept for payment any of the Shares so tendered. Subject to the terms of the CVR Agreement, please make all payments regarding the CVRs as directed herein for payment of the cash consideration and enter in the CVR register to be maintained by the rights agent pursuant to the CVR Agreement the name(s) and address(es)

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appearing on the cover page of this Letter of Transmittal for each registered holder. The undersigned recognizes that Purchaser has no obligation, pursuant to the Special Payment Instructions, to transfer any Shares from the name(s) of the registered holder(s) thereof if Purchaser does not accept for payment any of the Shares so tendered.

The Offer is being made to all holders of the Shares. Purchaser is not aware of any jurisdiction in which the making of the Offer or the acceptance thereof would be prohibited by securities, "blue sky" or other valid laws or regulations of such jurisdiction. If Purchaser becomes aware of any U.S. state in which the making of the Offer or the acceptance of Shares pursuant thereto would not be in compliance with an administrative or judicial action taken pursuant to a U.S. state statute, Purchaser will make a good faith effort to comply with any such law or regulation. If, after such good faith effort, Purchaser cannot comply with any such law or regulation, the Offer will not be made to (nor will tenders be accepted from or on behalf of) the holders of Shares in such state. In any jurisdictions where applicable laws or regulations require the Offer to be made by a licensed broker or dealer, the Offer shall be deemed to be made on behalf of Purchaser by one or more registered brokers or dealers licensed under the laws or regulations of such jurisdiction to be designated by Purchaser.

This Letter of Transmittal is to be used by stockholders of IGM Biosciences, Inc. ("<u>IGM</u>") if certificates ("<u>Certificates</u>") for shares of common stock, par value $0.01 per share, of IGM (the "<u>Shares</u>") are to be forwarded herewith or if shares are held in the name of the registered holder(s) by the transfer agent.

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#### DESCRIPTION OF SHARES SURRENDERED

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| | | | |
|:---|:---|:---|:---|
| **Name(s) and Address(es) of Registered Holder(s) (Please fill in exactly as name(s) appear(s) on certificate(s)) (Attach additional signed list if necessary)** | **Certificate** <br>**Number(s)<sup>\*</sup>** | **Total Number of** <br>**Shares Represented** <br>**by Certificate(s) or** <br>**Held in Book-Entry** <br>**Form<sup>\*</sup>** | **Number of** <br>**Shares** <br>**Surrendered<sup>\*</sup>** |

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\*<br> Unless otherwise indicated, it will be assumed that all shares above of common stock are being tendered hereby.

☐<br> CHECK HERE IF TENDERED SHARES ARE BEING DELIVERED HEREWITH.

☐ CHECK HERE IF YOU HAVE LOST YOUR CERTIFICATE(S). BY CHECKING THIS BOX, YOU UNDERSTAND THAT YOU MUST CONTACT THE TRANSFER AGENT TO OBTAIN INSTRUCTIONS FOR REPLACING LOST CERTIFICATES. SEE INSTRUCTION 11. 

☐ CHECK HERE IF YOU ARE INSTRUCTING THE AGENT **<u>NOT</u>** TO ACCEPT YOUR SHARES FOR TENDER. 

#### NOTE: SIGNATURES MUST BE PROVIDED BELOW <br>

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>

#### PLEASE READ ACCOMPANYING INSTRUCTIONS CAREFULLY
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| |
|:---|
| **SPECIAL PAYMENT INSTRUCTIONS** <br>**(See Instructions 1, 5, 6 and 7)** |
| To be completed ONLY if the check for the Cash Amount for Shares accepted for payment and/or Certificates not tendered or not accepted for payment are to be issued in the name of someone other than the undersigned. |
| Issue check and/or Certificates to: |
| Name: |
| **(Please Print)** |
| Address: |
| **(Include Zip Code)** |
| **(Taxpayer Identification No. (e.g., Social Security No.)) (Also complete, as appropriate, IRS Form W-9 included below)** |

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| |
|:---|
| **SPECIAL DELIVERY INSTRUCTIONS** <br>**(See Instructions 1, 5, 6 and 7)** |
| To be completed ONLY if the check for the Cash Amount for Shares accepted for payment and/or Certificates evidencing Shares not tendered or not accepted are to be mailed to someone other than the undersigned or to the undersigned at an address other than that shown above.  |
| Mail check and/or Certificates to:  |
| Name:  |
| **(Please Print)**  |
| Address:  |
| **(Include Zip Code)**  |

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#### IMPORTANT <br>

#### STOCKHOLDER: YOU MUST SIGN BELOW <br>

#### (U.S. Holders: Please complete and return the IRS Form W-9 included below) <br>

#### (Non-U.S. Holders: Please obtain, complete and return appropriate IRS Form W-8) <br>

#### (Signature(s) of Holder(s) of Shares)

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| | |
|:---|:---|
| Dated: |  |
| Name(s): |  |
| Capacity (Full Title) (See Instruction 5): | **(Please Print)**  |
| Address: |  |
|  | **(Include Zip Code)**  |
| Area Code and Telephone No.: |  |
| Tax Identification No. (*e.g.*, Social Security No.) (See IRS Form W-9 included below): | Tax Identification No. (*e.g.*, Social Security No.) (See IRS Form W-9 included below): |
| (Must be signed by registered holder(s) exactly as name(s) appear(s) on Certificate(s) or by person(s) authorized to become registered holder(s) by Certificates and documents transmitted herewith. If signature is by a trustee, executor, administrator, guardian, attorney-in-fact, agent, officer of a corporation or other person acting in a fiduciary or representative capacity, please set forth full title and see Instruction 5. For information concerning signature guarantees, see Instruction 1) | (Must be signed by registered holder(s) exactly as name(s) appear(s) on Certificate(s) or by person(s) authorized to become registered holder(s) by Certificates and documents transmitted herewith. If signature is by a trustee, executor, administrator, guardian, attorney-in-fact, agent, officer of a corporation or other person acting in a fiduciary or representative capacity, please set forth full title and see Instruction 5. For information concerning signature guarantees, see Instruction 1) |

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#### Guarantee of Signature(s) <br>

#### (If Required—See Instructions)

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| | |
|:---|:---|
| **[Place Stamp Here]** |  |
| Authorized Signature: |  |
| Name: |  |
| Name of Firm: |  |
| Address: |  |
|  | **(Include Zip Code)**  |
| Area Code and Telephone No.: |  |
| Dated:<u> </u>, 2025 |  |

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#### INSTRUCTIONS <br>

#### FORMING PART OF THE TERMS AND CONDITIONS OF THE OFFER
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;1. GUARANTEE OF SIGNATURES. No signature guarantee is required on this Letter of Transmittal: (a) if this Letter of Transmittal is signed by the registered holder(s) of Shares tendered herewith, unless such registered holder has completed either the box entitled "Special Payment Instructions" or the box entitled "Special Delivery Instructions" on this Letter of Transmittal; or (b) if such Shares are tendered for the account of a financial institution (including most commercial banks, savings and loan associations and brokerage houses) that is a member in good standing of the Securities Transfer Agents Medallion Program or any other "eligible guarantor institution," as such term is defined in Rule 17Ad-15 under the Securities Exchange Act of 1934, as amended (each, an "<u>Eligible Institution</u>"). In all other cases, including those referred to above, all signatures on this Letter of Transmittal must be guaranteed by an Eligible Institution. See Instruction 5.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;2. REQUIREMENTS OF TENDER. No alternative, conditional or contingent tenders will be accepted. In order for Shares to be validly tendered pursuant to the Offer, one of the following procedures must be followed:

For Shares held as physical certificates, the Certificates representing tendered Shares, a properly completed and duly executed Letter of Transmittal, together with any required signature guarantees, and any other documents required by this Letter of Transmittal, must be received by the Depositary and Paying Agent at one of its addresses set forth on the front page of this Letter of Transmittal before the Expiration Date.

For Shares held in book-entry form, a properly completed and duly executed Letter of Transmittal, together with any required signature guarantees, and any other required documents, must be received by the Depositary and Paying Agent at the appropriate address set forth on the front page of this Letter of Transmittal before the Expiration Date.

**The method of delivery of Shares, Certificate(s), this Letter of Transmittal, and all other required documents, is at the election and risk of the tendering stockholder. Shares will be deemed delivered (and the risk of loss of Certificates will pass) only when actually received by the Depositary and Paying Agent. If delivery is by mail, then registered mail with return receipt requested, properly insured, is recommended. In all cases, sufficient time should be allowed to ensure timely delivery.** 

No fractional Shares will be purchased. By executing this Letter of Transmittal, the tendering stockholder waives any right to receive any notice of the acceptance for payment of Shares.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;3. INADEQUATE SPACE. If the space provided herein is inadequate, Certificate numbers, the number of Shares represented by such Certificates and/or the number of Shares tendered should be listed on a separate signed schedule attached hereto.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;4. PARTIAL TENDERS (NOT APPLICABLE TO STOCKHOLDERS WHO TENDER BY BOOK-ENTRY TRANSFER). If fewer than all the Shares represented by any Certificate delivered to the Depositary and Paying Agent are to be tendered, fill in the number of Shares which are to be tendered in the box entitled "Total Number of Shares Tendered." In such case, a new Certificate for the remainder of the Shares represented by the old Certificate will be sent to the person(s) signing this Letter of Transmittal, unless otherwise provided in the appropriate box on this Letter of Transmittal, as promptly as practicable following the expiration or termination of the Offer. All Shares represented by Certificates delivered to the Depositary and Paying Agent will be deemed to have been tendered unless otherwise indicated.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;5. SIGNATURES ON LETTER OF TRANSMITTAL AND ENDORSEMENTS.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(a) <u>Exact Signatures</u>. If this Letter of Transmittal is signed by the registered holder(s) of the Shares tendered hereby, the signature(s) must correspond with the name(s) as written on the face of the Certificates without alteration, enlargement or any change whatsoever.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(b) <u>Joint Holders</u>. If any of the Shares tendered hereby are held of record by two or more persons, all such persons must sign this Letter of Transmittal.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(c) <u>Different Names on Certificates</u>. If any of the Shares tendered hereby are registered in different names on different Certificates, it will be necessary to complete, sign and submit as many separate Letters of Transmittal as there are different registrations of Certificates.

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(d) <u>Endorsements</u>. If this Letter of Transmittal is signed by the registered holder(s) of the Shares tendered hereby, no endorsements of Certificates or separate stock powers are required. If this Letter of Transmittal is signed by a person other than the registered holder(s) of the Shares tendered hereby, signature(s) must be guaranteed by an Eligible Institution. See Instruction 1.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(f) <u>Evidence of Fiduciary or Representative Capacity</u>. If this Letter of Transmittal or any Certificate is signed by a trustee, executor, administrator, guardian, attorney-in-fact, officer of a corporation or other legal entity or other person acting in a fiduciary or representative capacity, such person should so indicate when signing, and proper evidence satisfactory to the Depositary and Paying Agent of the authority of such person so to act must be submitted. Proper evidence of authority includes a power of attorney, a letter of testamentary or a letter of appointment.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6. STOCK TRANSFER TAXES. Except as otherwise provided in this Instruction 6, Purchaser or any successor entity thereto will pay all stock transfer taxes with respect to the transfer and sale of any Shares pursuant to the Offer (for the avoidance of doubt, transfer taxes do not include U.S. federal income taxes or withholding taxes). If, however, consideration is to be paid to, or if Certificate(s) for Shares not tendered or not accepted for payment are to be registered in the name of, any person(s) other than the registered holder(s), or if tendered Certificate(s) for Share(s) are registered in the name of any person(s) other than the person(s) signing this Letter of Transmittal, Purchaser or any successor entity thereto will not be responsible for any stock transfer or similar taxes (whether imposed on the registered holder(s) or such other person(s) or otherwise) payable on account of the transfer to such other person(s) and no consideration shall be paid in respect of such Share(s) unless evidence satisfactory to Purchaser or any successor entity thereto of the payment of such taxes, or the inapplicability of such taxes, is submitted.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;7. SPECIAL PAYMENT AND DELIVERY INSTRUCTIONS. If a check is to be issued for the Cash Amount of any Shares tendered by this Letter of Transmittal in the name of, and, if appropriate, Certificates for Shares not tendered or not accepted for payment are to be issued or returned to, any person(s) other than the signer of this Letter of Transmittal or if a check and, if appropriate, such Certificates are to be returned to any person(s) other than the person(s) signing this Letter of Transmittal or to an address other than that shown in this Letter of Transmittal, the appropriate boxes on this Letter of Transmittal must be completed.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8. TAX WITHHOLDING. Under U.S. federal income tax laws, the Depositary and Paying Agent may be required to withhold a portion of any payments made to certain stockholders pursuant to the Offer. To avoid such backup withholding, a tendering stockholder that is a U.S. person (as defined for in the instructions to IRS Form W-9, a "<u>U.S. person</u>"), and, if applicable, each other U.S. payee, is required to: (a) provide the Depositary and Paying Agent with a correct Taxpayer Identification Number ("<u>TIN</u>") on IRS Form W-9, which is included herein, and to certify, under penalty of perjury, that such number is correct and that such stockholder or payee is not subject to backup withholding of U.S. federal income tax; or (b) otherwise establish a basis for exemption from backup withholding. Failure to provide the information on the IRS Form W-9 may subject the tendering stockholder or payee to backup withholding at the then applicable rate (currently 24%), and such stockholder or payee may be subject to a penalty imposed by the IRS. See the enclosed IRS Form W-9 and the instructions thereto for additional information.

Certain stockholders or payees (including, among others, corporations) may not be subject to backup withholding. Exempt stockholders or payees that are U.S. persons should furnish their TIN, check the appropriate box on the IRS Form W-9 and sign, date and return the IRS Form W-9 to the Depositary and Paying Agent in order to avoid backup withholding. A stockholder or other payee that is not a U.S. person can establish an exemption from backup withholding: (a) by providing the Depositary and Paying Agent with a properly completed IRS Form W-8BEN or IRS Form W-8BEN-E, as applicable, or other appropriate IRS Form W-8, signed under penalties of perjury, attesting to such stockholder's or payee's foreign status; or (b) by otherwise establishing an exemption. An appropriate IRS Form W-8 may be obtained from the Depositary and Paying Agent or the IRS website (*www.irs.gov*). The Depositary and Paying Agent may withhold tax at a 30% rate (subject to certain exceptions) on payments made to non-U.S. stockholders pursuant to the Offer, unless the Depositary and Paying Agent determines that a reduced rate under an applicable income tax treaty or exemption from withholding is applicable. See "<u>The Tender Offer—Section 3. Procedures for Tendering Shares</u>" and "<u>Special Factors—Section 6. Material U.S. Federal Income Tax Consequences of the Offer and the Merger</u>" of the Offer to Purchase.

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Backup withholding is not an additional tax. Rather, the U.S. federal income tax liability of persons subject to backup withholding will be reduced by the amount of tax withheld. If backup withholding results in an overpayment of taxes, a refund or credit may be obtained from the IRS if eligibility is established and appropriate procedure is followed. Stockholders are urged to consult their tax advisors regarding the application of U.S. federal income tax withholding, including eligibility for a withholding tax reduction or exemption, and the IRS refund procedure.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9. IRREGULARITIES. All questions as to the validity, form, eligibility (including time of receipt) and acceptance for payment of any tender of Shares will be determined by the Depositary and Paying Agent, in its sole discretion, which determination shall be final and binding on all parties. Purchaser reserves the absolute right to reject any and all tenders determined by it not to be in proper form or the acceptance for payment of which may, in the opinion of its counsel, be unlawful. Purchaser also reserves the absolute right to waive any defect or irregularity in the tender of any Shares of any particular stockholder, whether or not similar defects or irregularities are waived in the case of other stockholders. No tender of Shares will be deemed to have been validly made until all defects and irregularities have been waived or cured within such time as Purchaser shall determine. None of Purchaser, the Depositary and Paying Agent, the Information Agent or any other person will be under any duty to give notice of any defects or irregularities in tenders or incur any liability for failure to give any such notice. Purchaser's interpretation of the terms and conditions of the Offer (including the Letter of Transmittal and the instructions thereto) will be final and binding.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10. QUESTIONS AND REQUESTS FOR ADDITIONAL COPIES. The Information Agent may be contacted at the address and telephone number set forth on the last page of this Letter of Transmittal for questions and/or requests for additional copies of the Offer to Purchase, this Letter of Transmittal and other tender offer materials. You may also contact your broker, dealer, commercial bank, trust company or other nominee for assistance. Such copies will be furnished promptly at Purchaser's expense.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;11. LOST, STOLEN DESTROYED OR MUTILATED CERTIFICATES. If any Certificate has been lost, stolen, destroyed or mutilated, the stockholder should promptly notify the Transfer Agent toll-free at 1-800-937-5449. The stockholder will then be instructed as to the steps that must be taken in order to replace such Certificates. You may be required to post a bond to secure against the risk that the Certificate(s) may be subsequently recirculated. This Letter of Transmittal and related documents cannot be processed until the procedures for replacing lost, destroyed or stolen certificates have been followed. You are urged to contact the Transfer Agent immediately in order to receive further instructions and for a determination of whether you will need to post a bond and to permit timely processing of this documentation. This Letter of Transmittal and related documents cannot be processed until the procedures for replacing lost, destroyed, mutilated or stolen Certificates have been followed.

**Certificates evidencing tendered Shares, as well as this Letter of Transmittal, properly completed and duly executed, with any required signature guarantees, and any other documents required by this Letter of Transmittal, must be received before the Expiration Date.** 

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#### IMPORTANT U.S. FEDERAL TAX INFORMATION
Under federal income tax law, a stockholder who is a U.S. person (as defined in the instructions to IRS Form W-9) surrendering Shares must, unless an exemption applies, provide the Depositary and Paying Agent (as payer) with the stockholder's correct TIN on IRS Form W-9, a copy of which is included in this Letter of Transmittal. If the stockholder is an individual, then the stockholder's TIN is generally such stockholder's Social Security number. If the correct TIN is not provided, then the stockholder may be subject to a penalty imposed by the IRS and payments of cash to the stockholder (or other payee) pursuant to the Offer may be subject to U.S. federal backup withholding at the then applicable rate (currently imposed at a rate of 24%).

Certain stockholders (including, among others, certain corporations and certain foreign individuals and entities) may not be subject to backup withholding and reporting requirements. In order for an exempt stockholder who is not a U.S. person (as defined in the instructions to IRS Form W-9) to avoid backup withholding, such person should complete, sign and submit an appropriate IRS Form W-8 signed under penalties of perjury, attesting to his, her or its exempt status. IRS Forms W-8 can be obtained from the Depositary and Paying Agent, or from the IRS website at: http://www.irs.gov/w8. Such stockholders should consult a tax advisor to determine which version of IRS Form W-8 is appropriate. Exempt stockholders who are U.S. persons should furnish their TIN, check the "Exempt payee" box on the IRS Form W-9 and sign, date and return the IRS Form W-9 to the Depositary and Paying Agent in order to avoid erroneous backup withholding. See the instructions enclosed with the IRS Form W-9 included in this Letter of Transmittal for additional instructions.

If backup withholding applies, the Depositary and Paying Agent is required to withhold and pay over to the IRS a portion of any payment made to a stockholder. Backup withholding is not an additional tax. Rather, the federal income tax liability of persons subject to backup withholding may be reduced by the amount of tax withheld provided the required information is timely provided to the IRS. If backup withholding results in an overpayment of taxes, a refund may be obtained from the IRS provided the required information is timely provided to the IRS.

EACH STOCKHOLDER IS URGED TO CONSULT WITH HIS, HER OR ITS TAX ADVISOR REGARDING THE TAX CONSEQUENCES OF THE TRANSACTION IN LIGHT OF THEIR PARTICULAR CIRCUMSTANCES.

#### Purpose of IRS Form W-9
To prevent backup withholding on payments that are made to a stockholder with respect to Shares purchased pursuant to the Offer, the stockholder is required to notify the Depositary and Paying Agent of the stockholder's correct TIN by completing the IRS Form W-9 included in this Letter of Transmittal certifying that (1) the TIN provided on the IRS Form W-9 is correct (or that such stockholder is awaiting a TIN), (2) the stockholder is not subject to backup withholding because (i) the stockholder is exempt from backup withholding, (ii) the stockholder has not been notified by the IRS that the stockholder is subject to backup withholding as a result of a failure to report all interest and dividends or (iii) the IRS has notified the stockholder that the stockholder is no longer subject to backup withholding, and (3) the stockholder is a U.S. person (as defined in the instructions to IRS Form W-9).

#### What Number to Give the Depositary and Paying Agent
The tendering stockholder is required to give the Depositary and Paying Agent the TIN, generally the Social Security number or employer identification number, of the record holder of all Shares tendered hereby. If such Shares are in more than one name or are not in the name of the actual owner, consult the instructions enclosed with the IRS Form W-9 included in this Letter of Transmittal for additional guidance on which number to report.

**NOTE: FAILURE TO COMPLETE AND RETURN THE IRS FORM W-9 INCLUDED IN THIS LETTER OF TRANSMITTAL MAY RESULT IN BACKUP WITHHOLDING OF A PORTION OF ANY PAYMENTS MADE TO YOU PURSUANT TO THE OFFER. PLEASE REVIEW THE INSTRUCTIONS ENCLOSED WITH THE IRS FORM W-9 INCLUDED IN THIS LETTER OF TRANSMITTAL FOR ADDITIONAL DETAILS. YOU MUST COMPLETE THE FOLLOWING CERTIFICATE IF YOU WROTE "APPLIED FOR" IN THE SPACE FOR THE TIN ON THE IRS FORM W-9.** 

11<br>

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![](ny20051934x1_w9image01.jpg) <br>

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![](ny20051934x1_w9image02.jpg) <br>

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![](ny20051934x1_w9image03.jpg) <br>

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![](ny20051934x1_w9image04.jpg) <br>

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![](ny20051934x1_w9image05.jpg) <br>

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![](ny20051934x1_w9image06.jpg) <br>

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*The Depositary and Paying Agent for the Offer Is:*

Broadridge Corporate Issuer Solutions, LLC<br>

#### Mail or deliver the Letter of Transmittal, together with the certificate(s) (if any) representing your shares, to :

---

| | |
|:---|:---|
| *If delivering by hand, express mail, courier* <br>*or other expedited service:* | *If delivering by mail:* |
| Broadridge, Inc. <br>Attention: BCIS IWS <br>51 Mercedes Way <br>Edgewood, NY 11717 | Broadridge, Inc. <br>Attention: BCIS Re-Organization Dept. <br>P.O. Box 1317 <br>Brentwood, NY 11717-0718 |

---

MacKenzie Partners, Inc. (the "<u>Information Agent</u>") may be contacted at its address and telephone number listed below for questions and/or requests for additional copies of the Offer to Purchase, this Letter of Transmittal and other tender offer materials. You may also contact your broker, dealer, commercial bank, trust company or other nominee for assistance. Such copies will be furnished promptly at Purchaser's expense.

*The Information Agent for the Offer is:*![](logo_mackenzie4x1.jpg)<br>

&nbsp;&nbsp;&nbsp;&nbsp;<br>

7 Penn Plaza<br>

New York, New York 10001<br>

(212) 929-5500

You may call MacKenzie Partners, Inc., the Information Agent for the Offer, toll-free at (800) 322-2885 or email them at tenderoffer@mackenziepartners.com.

## Ex-99.(A)(1)(C)

#### Exhibit (a)(1)(C)

#### Offer to Purchase <br>

#### All Outstanding Shares of Common Stock <br>

#### of <br>

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>

### IGM BIOSCIENCES, INC. <br>

### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>

#### at <br>
**A Cash Amount of $1.247 per Share, Plus One Non-Transferable Contractual Contingent Value Right for Each Share ("<u>CVR</u>"), Which Represents the Right to Receive One or More Potential Cash Payments, Contingent upon: (i) the Receipt of Proceeds from Any CVR Product or Company Patent Disposition that Occurs Within One (1) Year Following the Merger Closing Date and Such Proceeds Are Received by or Otherwise Due to Parent or Any of Its Affiliates by the First (1st) Anniversary Following the Merger Closing Date; and (ii) Closing Net Cash in Excess of $82,000,000, As Determined Five (5) Business Days Prior to the Merger Closing Date, as Described in the CVR Agreement.** 

#### Pursuant to the Offer to Purchase <br>

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>

#### Dated July 16, 2025 <br>

#### by <br>

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>

#### CONCENTRA BIOSCIENCES, LLC <br>

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>

#### CONCENTRA MERGER SUB V, INC. <br>

#### a wholly owned subsidiary of Purchaser<br>

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>

#### TANG CAPITAL PARTNERS, LP <br>

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>

#### TANG CAPITAL MANAGEMENT, LLC <br>

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>
**THE OFFER AND WITHDRAWAL RIGHTS WILL EXPIRE ONE MINUTE AFTER 11:59 P.M. EASTERN TIME ON AUGUST 13, 2025, UNLESS THE OFFER IS EXTENDED OR EARLIER TERMINATED.**

#### July 16, 2025
To Brokers, Dealers, Commercial Banks, Trust Companies and Other Nominees:

We have been engaged by Concentra Biosciences, LLC, a Delaware limited liability company ("<u>Parent</u>" or "<u>Purchaser</u>"), to act as Depositary and Paying Agent in connection with Purchaser's offer to purchase all of the outstanding shares of common stock, par value $0.01 per share (the "<u>Shares</u>"), of IGM Biosciences, Inc., a Delaware corporation ("<u>IGM</u>"), for: (i) $1.247 per Share in cash (the "<u>Cash Amount</u>"); plus (ii) one non-transferable contractual contingent value right for each Share (each, a "<u>CVR,</u>" and each CVR together with the Cash Amount, the "Offer Price"), all upon the terms and subject to the conditions described in the Offer to Purchase (together with any amendments or supplements thereto, the "<u>Offer to Purchase</u>") and in the related Letter of Transmittal (together with any amendments or supplements thereto, the "<u>Letter of Transmittal</u>" and, together with the Offer to Purchase, the "<u>Offer</u>") enclosed herewith. Please furnish copies of the enclosed materials to those of your clients for whom you hold Shares registered in your name or in the name of your nominee. On July 1, 2025, the IGM board of directors (the "<u>IGM Board</u>") at a duly called and held meeting, duly and by unanimous vote: (i) determined that the terms of the Merger Agreement, the Offer and the other transactions contemplated by the Merger Agreement and the CVR Agreement (collectively, the "Transactions") are advisable, fair to, and in the best interests of, IGM and IGM's stockholders; (ii) approved and declared advisable the Merger Agreement and the Transactions; (iii) authorized and approved the execution, delivery and performance by IGM of the Merger Agreement and the consummation by IGM of the Transactions; (iv) resolved to recommend that IGM's stockholders accept the Offer and tender their shares of IGM Common Stock in the Offer; and (v) resolved that the Merger Agreement and the Merger shall be governed by and effected under Section 251(h) of the DGCL.

Concurrently with the execution of the Merger Agreement, and as a condition and inducement to IGM's willingness to enter into the Merger Agreement, Tang Capital Partners, LP, a Delaware limited partnership ("<u>TCP</u>" or

------

"<u>Guarantor</u>") and sole member of Parent, delivered to IGM a duly executed limited guaranty (the "<u>Limited</u> <u>Guaranty</u>"), dated as of the date of the Merger Agreement, in favor of IGM, in respect of certain obligations of Parent and Concentra Merger Sub V, Inc., a Delaware corporation ("<u>Merger Sub</u>") under the Merger Agreement and the CVR Agreement. Certain obligations under the Limited Guaranty are subject to a cap of $78,000,000, which includes certain Enforcement Costs, under the Merger Agreement and an amount equivalent to the CVR Proceeds under the CVR Agreement. Tang Capital Management, LLC, a Delaware limited liability company ("<u>TCM</u>"), is the sole manager of Parent and the general partner of TCP. Accordingly, TCP and TCM are considered co-offerors in the Offer.

#### The Offer is not subject to any financing conditions. Certain conditions to the Offer are described in Section 9 of the Offer to Purchase.
For your information and for forwarding to your clients for whom you hold Shares registered in your name or in the name of your nominee, we are enclosing the following documents:

1.<br> The Offer to Purchase;

2.<br> The Letter of Transmittal for the information of your clients, together with the included Internal Revenue Service Form W-9;

3.<br> IGM's solicitation/recommendation statement on Schedule 14D-9; and

4. A form of letter which may be sent to your clients for whose accounts you hold Shares registered in your name or in the name of your nominee, with space provided for obtaining such clients' instructions with regard to the Offer 

**Your prompt action is requested. We urge you to contact your clients as promptly as possible. Please note that the Offer and withdrawal rights will expire one minute after 11:59 p.m., Eastern Time, on August 13, 2025, unless the Offer is extended or earlier terminated.** 

For Shares to be properly tendered pursuant to the Offer, the share certificates (if any) or confirmation of receipt of such Shares under the procedure for book-entry transfer through The Depository Trust Company ("<u>DTC</u>") with an Agent's Message (as defined in Section 3 of the Offer to Purchase) in lieu of such Letter of Transmittal, and any other documents required in the Letter of Transmittal, must be timely received by the Depositary and Paying Agent, all in accordance with the Offer to Purchase and the Letter of Transmittal.

Purchaser will not pay any fees or commissions to any broker or dealer or other person (other than the Depositary and Paying Agent and the Information Agent as described in the Offer to Purchase) for soliciting tenders of Shares pursuant to the Offer. Purchaser will, however, upon request, reimburse brokers, dealers, commercial banks and trust companies for reasonable and necessary costs and expenses incurred by them in forwarding materials to their customers. The Surviving Corporation (as defined in the Offer to Purchase) will pay all stock transfer taxes applicable to its purchase of Shares pursuant to the Offer, subject to Instruction 6 of the Letter of Transmittal. **UNDER NO CIRCUMSTANCES WILL INTEREST BE PAID ON THE OFFER PRICE FOR THE SHARES, REGARDLESS OF ANY EXTENSION OF THE OFFER OR ANY DELAY IN MAKING PAYMENT.**

Any inquiries you may have with respect to the Offer should be addressed to, and additional copies of the enclosed materials may be obtained from, the Information Agent for the Offer at the addresses and telephone numbers set forth on the back cover of the Offer to Purchase.

Very truly yours,

Broadridge Corporate Issuer Solutions, LLC

**Nothing contained herein or in the enclosed documents shall render you the agent of the Purchaser, the Information Agent or the Depositary and Paying Agent or any affiliate of any of them or authorize you or any other person to use any document or make any statement on behalf of any of them in connection with the Offer other than the enclosed documents and the statements contained therein.** 

------

#### The Information Agent for the Offer is:
![](logo_mackenzie4x2.jpg)<br>

7 Penn Plaza<br>

New York, New York 10001<br>

(212) 929-5500

You may call MacKenzie Partners, Inc., the Information Agent for the Offer, toll-free at (800) 322-2885 or email them at tenderoffer@mackenziepartners.com.

## Ex-99.(A)(1)(D)

#### Exhibit (a)(1)(D)

#### Offer to Purchase<br>

#### All Outstanding Shares of Common Stock <br>

#### of<br>

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>

### IGM BIOSCIENCES, INC. <br>

### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>

#### at <br>
**A Cash Amount of $1.247 per Share, Plus One Non-Transferable Contractual Contingent Value Right for Each Share ("<u>CVR</u>"), Which Represents the Right to Receive One or More Potential Cash Payments, Contingent upon: (i) the Receipt of Proceeds from Any CVR Product or Company Patent Disposition that Occurs Within One (1) Year Following the Merger Closing Date and Such Proceeds Are Received by or Otherwise Due to Parent or Any of Its Affiliates by the First (1st) Anniversary Following the Merger Closing Date; and (ii) Closing Net Cash in Excess of $82,000,000, As Determined Five (5) Business Days Prior to the Merger Closing Date, as Described in the CVR Agreement.** 

<br> #### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>

#### by <br>

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>

#### CONCENTRA BIOSCIENCES, LLC <br>

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>

#### CONCENTRA MERGER SUB V, INC. <br>

#### a wholly owned subsidiary of Purchaser<br>

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>

#### TANG CAPITAL PARTNERS, LP <br>

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>

#### TANG CAPITAL MANAGEMENT, LLC <br>

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>
**THE OFFER AND WITHDRAWAL RIGHTS WILL EXPIRE ONE MINUTE AFTER 11:59 P.M. EASTERN TIME ON AUGUST 13, 2025, UNLESS THE OFFER IS EXTENDED OR EARLIER TERMINATED.**

#### July 16, 2025
To Our Clients:

Enclosed for your consideration are the Offer to Purchase, dated July 16, 2025 (together with any amendments or supplements thereto, the "<u>Offer to Purchase</u>"), and the related Letter of Transmittal (together with any amendments or supplements thereto, the "<u>Letter of Transmittal</u>" and, together with the Offer to Purchase, the "<u>Offer</u>") in connection with the offer by Concentra Biosciences, LLC, a Delaware limited liability company ("<u>Parent</u>" or "<u>Purchaser</u>"), to purchase, subject to certain conditions, all of the outstanding shares of common stock, par value $0.01 per share (the "Shares"), of IGM Biosciences, Inc., a Delaware corporation ("<u>IGM</u>"), for: (i) $1.247 per Share in cash (the "<u>Cash Amount</u>"); plus (ii) one non-transferable contractual contingent value right for each Share (each, a "<u>CVR,</u>" and each CVR together with the Cash Amount, the "<u>Offer Price</u>"), all upon the terms and subject to the conditions described in the Offer to Purchase and the Letter of Transmittal.

Also enclosed is IGM's Solicitation/Recommendation Statement on Schedule 14D-9.

We or our nominees are the holder of record of Shares held for your account. A tender of such Shares can be made only by us as the holder of record and pursuant to your instructions.

**The Letter of Transmittal accompanying this letter is furnished to you for your information only and cannot be used by you to tender Shares held by us for your account.** 

**We request instructions as to whether you wish us to tender any or all of the Shares held by us for your account, upon the terms and subject to the conditions set forth in the enclosed Offer to Purchase and the Letter of Transmittal.** 

------

Please note carefully the following:

1. The Offer Price for the Offer is (i) $1.247 per Share in cash plus (ii) one non-transferable contractual contingent value right for each Share, in each case, to be paid net to you of any applicable tax withholding and without interest. 

2.<br> The Offer is being made for all outstanding voting and non-voting Shares.

3. The Offer is being made pursuant to the Agreement and Plan of Merger, dated as of July 1, 2025 (together with any amendments or supplements thereto, the "<u>Merger Agreement</u>"), among IGM, Parent and Concentra Merger Sub V, Inc., a Delaware corporation ("<u>Merger Sub</u>") and a wholly owned subsidiary of Purchaser, pursuant to which, after the completion of the Offer and the satisfaction or waiver of certain conditions, Merger Sub will be merged with and into IGM, without a meeting or any further action of the IGM stockholders in accordance with Section 251(h) of the General Corporation Law of the State of Delaware (the "<u>DGCL</u>"), and IGM will be the surviving corporation and a wholly owned subsidiary of Parent (such corporation, the "<u>Surviving Corporation</u>" and such merger, the "<u>Merger</u>"). 

4. Concurrently with the execution of the Merger Agreement, and as a condition and inducement to IGM's willingness to enter into the Merger Agreement, Tang Capital Partners, LP, a Delaware limited partnership ("<u>TCP</u>" or "<u>Guarantor</u>") and sole member of Parent, delivered to IGM a duly executed limited guaranty (the "<u>Limited Guaranty</u>"), dated as of the date of the Merger Agreement, in favor of IGM, in respect of certain obligations of Parent and Merger Sub under the Merger Agreement and the CVR Agreement. Certain obligations under the Limited Guaranty are subject to a cap of $78,000,000, which includes certain Enforcement Costs, under the Merger Agreement and an amount equivalent to the CVR Proceeds under the CVR Agreement. Tang Capital Management, LLC, a Delaware limited liability company ("<u>TCM</u>"), is the sole manager of Parent and the general partner of TCP. Accordingly, TCP and TCM are considered co-offerors in the Offer. 

5.<br> No appraisal rights are available to the holders of record or beneficial owners of Shares in connection with the Offer.

However, if the Offer is successful and the Merger is consummated, stockholders of record or beneficial owners of Shares who: (i) did not tender their Shares in the Offer (or who had tendered but subsequently validly withdrawn such tender, and not otherwise waived their appraisal rights); (ii) otherwise comply with the applicable requirements and procedures of Section 262 of the DGCL; and (iii) do not thereafter withdraw their demand for appraisal of such Shares or otherwise lose their appraisal rights, in each case in accordance with the DGCL, will be entitled to demand appraisal of their Shares and receive in lieu of the consideration payable in the Merger a cash payment equal to the "fair value" of their Shares, as determined by the Delaware Court of Chancery, in accordance with Section 262 of the DGCL. If you choose to exercise your appraisal rights in connection with the Merger and you properly demand and perfect such rights in accordance with Section 262 of the DGCL, you may be entitled to payment for your Shares based on a judicial determination of the fair value of your Shares plus interest, if any, on the amount determined to be fair value.

6. On July 1, 2025, the IGM board of directors (the "<u>IGM Board</u>") at a duly called and held meeting, duly and by unanimous vote: (i) determined that the terms of the Merger Agreement, the Offer and the other transactions contemplated by the Merger Agreement and the CVR Agreement (collectively, the "<u>Transactions</u>") are advisable, fair to, and in the best interests of, IGM and IGM's stockholders; (ii) approved and declared advisable the Merger Agreement and the Transactions; (iii) authorized and approved the execution, delivery and performance by IGM of the Merger Agreement and the consummation by IGM of the Transactions; (iv) resolved to recommend that IGM's stockholders accept the Offer and tender their shares of IGM Common Stock in the Offer; and (v) resolved that the Merger Agreement and the Merger shall be governed by and effected under Section 251(h) of the DGCL. 

7.<br> The Offer and withdrawal rights will expire one minute after 11:59 p.m., Eastern Time, on August 13, 2025, unless the Offer is extended or earlier terminated.

8.<br> The Offer is not subject to any financing conditions. The Offer is conditioned on, among other things, there being, as of the Offer Closing Time, validly tendered (and not validly withdrawn) pursuant to the

2<br>

------

Offer a number of Shares that, together with all Shares (if any) otherwise owned by Purchaser or any of its and its "affiliates" (as defined in Section 251(h)(6)(a) of the DGCL), would represent at least one Share more than 50% of the total number of voting Shares of Common Stock issued and outstanding at the Offer Closing Time. The Offer is also subject to customary conditions set forth in the Offer to Purchase and described in Section 9 of the Offer to Purchase.

9.<br> Any transfer taxes applicable to the sale of Shares to Purchaser pursuant to the Offer will be paid by the Surviving Corporation (as defined in the Offer to Purchase), except as otherwise provided in the Letter of Transmittal.

If you wish to have us tender any or all of your Shares, then please so instruct us by completing, executing, detaching and returning to us the Instruction Form on the detachable part hereof. An envelope to return your instructions to us is enclosed. If you authorize tender of your Shares, then all such Shares will be tendered unless otherwise specified on the Instruction Form.

**Your prompt action is requested. Your Instruction Form should be forwarded to us in ample time to permit us to submit the tender on your behalf before the expiration of the Offer.** 

**UNDER NO CIRCUMSTANCES WILL INTEREST BE PAID ON THE OFFER PRICE FOR THE SHARES, REGARDLESS OF ANY EXTENSION OF THE OFFER OR ANY DELAY IN MAKING PAYMENT.** 

The Offer is not being made to, nor will tenders be accepted from or on behalf of, holders of Shares in any jurisdiction in which the making of the Offer or acceptance thereof would not be in compliance with the laws of such jurisdiction, and Purchaser is not aware of any jurisdiction in which the making of the Offer or the tender of Shares in connection therewith would not be in compliance with the laws of such jurisdiction. If Purchaser becomes aware of any jurisdiction in which the making of the Offer would not be in compliance with applicable law, Purchaser will make a good faith effort to comply with any such law. If, after such good faith effort, Purchaser cannot comply with any such law, the Offer will not be made to (nor will tenders be accepted from or on behalf of) the holders of Shares residing in such jurisdiction. In those jurisdictions where applicable laws require that the Offer be made by a licensed broker or dealer, the Offer will be deemed to be made on behalf of Purchaser by one or more registered brokers or dealers licensed under the laws of such jurisdiction to be designated by Purchaser.

3<br>

------

#### INSTRUCTION FORM <br>

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>

#### With Respect to the Offer to Purchase for Cash <br>

#### All Outstanding Shares of Common Stock <br>

#### of<br>

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>

### IGM BIOSCIENCES, INC. <br>

### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>

#### at <br>
**A Cash Amount of $1.247 per Share, Plus One Non-Transferable Contractual Contingent Value Right for Each Share ("<u>CVR</u>"), Which Represents the Right to Receive One or More Potential Cash Payments, Contingent upon: (i) the Receipt of Proceeds from Any CVR Products or Company Patent Disposition that Occurs Within One (1) Year Following the Merger Closing Date and Such Proceeds Are Received by or Otherwise Due to Parent or Any of Its Affiliates by the First (1st) Anniversary Following the Merger Closing Date; and (ii) Closing Net Cash in Excess of $82,000,000, As Determined Five (5) Business Days Prior to the Merger Closing Date, as Described in the CVR Agreement.** 

<br> #### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>

#### by <br>

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>

#### CONCENTRA BIOSCIENCES, LLC <br>

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>

#### CONCENTRA MERGER SUB V, INC. <br>

#### a wholly owned subsidiary of Purchaser<br>

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>

#### TANG CAPITAL PARTNERS, LP <br>

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>

#### TANG CAPITAL MANAGEMENT, LLC
The undersigned acknowledge(s) receipt of your letter and the enclosed Offer to Purchase, dated July 16, 2025 (together with any amendments or supplements thereto, the "<u>Offer to Purchase</u>"), and the related Letter of Transmittal (together with any amendments or supplements thereto, the "<u>Letter of Transmittal</u>" and, together with the Offer to Purchase, the "<u>Offer</u>"), in connection with the offer by Concentra Biosciences, LLC, a Delaware limited liability company ("<u>Parent</u>" or "<u>Purchaser</u>"), to purchase all of the outstanding shares of common stock, par value $0.01 per share (the "<u>Shares</u>"), of IGM Biosciences, Inc., a Delaware corporation ("<u>IGM</u>"), for: (i) $1.247 per Share in cash (the "<u>Cash Amount</u>"); plus (ii) one non-transferable contractual contingent value right for each Share (each, a "<u>CVR,</u>" and each CVR together with the Cash Amount, the "<u>Offer Price</u>"), all upon the terms and subject to the conditions described in the Offer to Purchase (together with any amendments or supplements hereto, the "<u>Offer to Purchase</u>") and the Letter of Transmittal (together with any amendments or supplements thereto, the "<u>Letter of Transmittal</u>"). Subject to the terms of the Merger Agreement (as defined below) and the CVR Agreement (as defined below), the Offer Price will be paid net of any applicable tax withholding and without interest. The undersigned hereby instruct(s) you to tender to Purchaser the number of Shares indicated below or, if no number is indicated, all Shares held by you for the account of the undersigned, upon the terms and subject to the conditions set forth in the Offer.

Concurrently with the execution of the Merger Agreement, and as a condition and inducement to IGM's willingness to enter into the Merger Agreement, Tang Capital Partners, LP, a Delaware limited partnership ("<u>TCP</u>" or "<u>Guarantor</u>") and sole member of Parent, delivered to IGM a duly executed limited guaranty (the "<u>Limited Guaranty</u>"), dated as of the date of the Merger Agreement, in favor of IGM, in respect of certain obligations of Parent and Concentra Merger Sub V, Inc., a Delaware corporation ("<u>Merger Sub</u>") and a wholly owned subsidiary of Purchaser, under the Merger Agreement and the CVR Agreement. Certain obligations under the Limited Guaranty are subject to a cap of $78,000,000, which includes certain Enforcement Costs, under the Merger Agreement and an amount equivalent to the CVR Proceeds under the CVR Agreement. Tang Capital Management, LLC, a Delaware limited liability company ("<u>TCM</u>"), is the sole manager of Parent and the general partner of TCP. Accordingly, TCP and TCM are considered co-offerors in the Offer.

The undersigned understands and acknowledges that all questions as to validity, form and eligibility of the tender of Shares submitted on the undersigned's behalf to Broadridge Corporate Issuer Solutions, LLC (the "<u>Paying and Depositary Agent</u>") will be determined by Purchaser (which may delegate power in whole or in part to the Paying and Depositary Agent) and such determination shall be final and binding.

4<br>

------

#### ACCOUNT NUMBER:

#### NUMBER OF SHARES BEING TENDERED HEREBY:   SHARES\*
**The method of delivery of this document is at the election and risk of the tendering stockholder. If delivery is by mail, then registered mail with return receipt requested, properly insured, is recommended. In all cases, sufficient time should be allowed to ensure timely delivery.** 

\*<br> Unless otherwise indicated, it will be assumed that all Shares held by us for your account are to be tendered.

Dated:<u> </u>, 2025

#### (Signature(s)) <br>

#### (Please Print Name(s))
Address:<u> </u>

#### Include Zip Code
Area Code and Telephone No.<u> </u>

Taxpayer Identification No. (e.g.) Social Security No. or Employer Identification No.)<u> </u>

5<br>

## Ex-99.(D)(2)

------

#### Exhibit (d)(2)

#### CONFIDENTIAL

![](ny20051934x1_exd2logo.jpg)

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., a Delaware corporation ("<u>we</u>" or the "<u>Company</u>") and Concentra Biosciences, LLC ("<u>you</u>" or "<u>Bidder</u>") (any such transaction being referred to herein as a "<u>Transaction</u>"), it is expected that each of the parties hereto will convey, furnish or otherwise make available to the other party and its Representatives (as defined below), Confidential Information (as defined below) for purposes of evaluating, negotiating, and consummating a Transaction (the "<u>Purpose</u>"). Each of the parties hereto hereby agrees to treat all Confidential Information of the other party hereto, all Evaluation Material (as defined below), and all Transaction Information (as defined below) in accordance with the provisions of this letter agreement, and to take or abstain from taking certain other actions set forth herein. The party hereto conveying, furnishing or otherwise making available Confidential Information hereunder is sometimes referred to herein, in such capacity, as the "<u>Disclosing Party</u>" and the party hereto receiving any such Confidential Information is sometimes referred to herein, in such capacity, as the "<u>Receiving Party</u>."

For purposes of this letter agreement, the following terms have the following respective meanings:

"<u>Confidential Information</u>" means all information, data, documents or materials concerning the Disclosing Party or any of its affiliates (including, without limitation, all information and other data about the Disclosing Party or any of its affiliates' business, capital structure, business plans, market positioning, operations, financial condition, results of operations, strategies, projections, forecasts, budgets, prospects, competitors, technology platform, products, product candidates, product roadmaps, clinical development, clinical trials, intellectual property, trade secrets and know how, personnel, assets, properties and liabilities) conveyed, furnished or otherwise made available by the Disclosing Party or any of its Representatives to the Receiving Party or any of its Representatives, whether prior to, on or following the date hereof, in connection with a Transaction, whether in written, electronic or other form or medium or conveyed verbally.

"<u>Evaluation Material</u>" means all reports, studies, analyses, interpretations, compilations, memoranda, notes and any other written or electronic materials prepared by the Receiving Party or any of its Representatives to the extent such materials contain, reflect or are derived or based, in whole or in part, upon any Confidential Information of the Disclosing Party.

Notwithstanding the foregoing or anything to the contrary set forth herein, for purposes of this letter agreement, the capitalized terms "Confidential Information" and "Evaluation Material" do not mean or include information which the Receiving Party can demonstrate (a) is already or becomes available or known to the Receiving Party or any of its Representatives on a non-confidential basis from a source other than the Disclosing Party or its Representatives, *provided* that such source is not known by the Receiving Party or any of its Representatives (in each case, after reasonable inquiry) to be bound by a confidentiality agreement with, or other direct or indirect obligation of confidentiality to, the Disclosing Party or any of its Representatives, (b) is or becomes generally known to the public other than as a result of a disclosure by the Receiving Party or any of its Representatives in breach of this letter agreement or any other obligation of confidentiality, or as a result of a disclosure by the Receiving Party or any of its Representatives pursuant to <u>Section 3</u> hereof, or (c) is or was independently developed by the Receiving Party or any of its Representatives without any reference to or use of any Confidential Information or Evaluation Material and without violation of any provision of this letter agreement.

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#### CONFIDENTIAL
<br> "<u>Representatives</u>" of a party means and includes such party's affiliates' and its and their respective directors, officers and other employees, legal counsel, accountants, financial advisors and other similar professional advisors; *provided*, *however*, that, in the case of Bidder, "Representatives" expressly excludes (a) any portfolio company of Bidder, including any portfolio company of any affiliate or affiliated fund of Bidder, and (b) any potential co-bidder with you for the Transaction or potential source of equity or debt capital or equity or debt financing in connection with a Transaction (any such potential co-bidder or source of capital or financing, a "<u>Financing Source</u>") unless (i) the Company consents in writing to make such Financing Source a "Representative" of Bidder under this letter agreement, and (ii) such Financing Source has executed an acknowledgment reasonably satisfactory to the Company of its obligations as a Representative under this letter agreement, in which event such Financing Source shall become Bidder's "Representative" for all purposes of and under this letter agreement (a Financing Source which has received approval to be a Representative, an "<u>Approved Financing Source</u>"). For purposes of this letter agreement, Bidder's "Representatives" include Tang Capital Partners, LP, parent to Bidder, and Tang Capital Management, LLC, general partner to Tang Capital Partners, LP.

"<u>person</u>" will be broadly interpreted to include, without limitation, the media and any corporation, company, partnership, limited liability company, trust, association, joint venture, governmental or regulatory body or agency or other entity or individual.

"<u>affiliate</u>" will have the meaning ascribed to such term in Rule 12b-2 of the General Rules and Regulations under the Securities Exchange Act of 1934, as amended (the "<u>Exchange Act</u>").

"<u>group</u>" shall have the meaning given to that term (or as that term is used) in Section 13(d)(3) of the Exchange Act.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;1. Each Receiving Party hereby agrees that it and its Representatives (a) will use Confidential Information of the Disclosing Party and all Evaluation Material derived therefrom solely for the Purpose and will not use any such Confidential Information or Evaluation Material for any other purpose, and (b) except as otherwise provided by <u>Section 3</u> of this letter agreement, will keep all Confidential Information of the Disclosing Party and all Evaluation Material derived therefrom strictly confidential and not disclose any Confidential Information of the Disclosing Party or any Evaluation Material derived therefrom to any person other than its Representatives who need to know such information solely for the Purpose (it being understood that such Representatives will be informed by the Receiving Party of the confidential nature of such information). Each Receiving Party further agrees that it and its Representatives will undertake commercially reasonable precautions to safeguard and protect the confidentiality of the Confidential Information of the Disclosing Party and the Evaluation Material derived therefrom and to prevent its and its Representatives from prohibited or unauthorized disclosure or uses of the Confidential Information of the Disclosing Party and the Evaluation Material derived therefrom.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;2. Except as otherwise provided by <u>Section 3</u> hereof, each party hereto hereby agrees that neither it nor any of its Representatives will, directly or indirectly, discuss with or disclose to any person, other than its Representatives who need to know such information solely for the Purpose, the fact that (a) the parties have entered into this letter agreement or the terms and conditions hereof, (b) Confidential Information has been made available to the Receiving Party or any of its Representatives, (c) either of the parties may be considering a Transaction and any potential terms, conditions or facts with respect to a Transaction, the status thereof or any investment arrangements designed to effect or facilitate a Transaction, (d) the parties or their Representatives have had, are having, or propose to have any discussions or negotiations with respect to a Transaction or that such party or its Representatives have conducted due diligence or attended management meetings with the other party or its Representatives, or (e) if applicable, that the parties have ceased, terminated or are otherwise no longer holding discussions or negotiations with respect to a Transaction (the matters referenced in the preceding clauses (a)-(e), inclusive, being referred to herein as "<u>Transaction Information</u>"). Notwithstanding anything herein to the contrary, nothing herein shall prohibit the Company from making any disclosures or announcements regarding the solicitation or negotiation of a Transaction or other Transaction Information so long as the Company does not specifically identify the Bidder in such disclosure or announcement. You hereby further agree that you and your Representatives will use the Transaction Information solely for the Purpose and will not use any such Transaction Information for any other purpose.

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#### <br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;3. In the event that the Receiving Party or any of its Representatives is required by law or regulation (including the rules and regulation of self-regulatory organizations), listing standard, or by any judicial, administrative, arbitral, or other similar proceeding or legal process ("<u>Law</u>") to disclose any Confidential Information of the Disclosing Party, the Evaluation Material derived therefrom, or Transaction Information or to make any other disclosure prohibited by this letter agreement in connection with any judicial, administrative, arbitral, or similar proceedings, in advance of such disclosure the Receiving Party will, unless and solely to the extent expressly prohibited by applicable Law, (a) promptly notify the Disclosing Party of such requirement, along with, to the extent applicable, a copy of any applicable notices describing such requirement, the circumstances surrounding such requirements, the reason that such disclosure is required and the time and place such disclosure is expected to be made, (b) provide the Disclosing Party with a copy, description and/or list (as applicable) of any such Confidential Information, Evaluation Material or Transaction Information the Receiving Party or any of its Representatives (as the case may be) intends or proposes to disclose in response to such requirement, and (c) reasonably cooperate with the Disclosing Party if and to the extent the Disclosing Party may seek to prevent or limit such disclosure, including, if requested by the Disclosing Party, taking all reasonable steps and cooperating with the Disclosing Party (at the Disclosing Party's expense) to resist or avoid any such disclosure. If the Receiving Party or any of its Representatives (as the case may be) and the Disclosing Party are unable to obtain a protective order preventing the required disclosure of such Confidential Information, Evaluation Material or Transaction Information, and the Disclosing Party refuses or fails to grant a waiver of the confidentiality restrictions set forth in this letter agreement after a request therefor is made by the Receiving Party or its Representatives (as the case may be) in writing (such request to be made as soon as reasonably practicable to allow the Disclosing Party a reasonable amount of time to respond thereto), the Receiving Party or its Representatives (as the case may be) may, on advice of counsel, disclose such Confidential Information, Evaluation Material or Transaction Information without liability hereunder, *provided* that the Receiving Party or its Representatives (as the case may be) disclose only that portion of such Confidential Information, Evaluation Material or Transaction Information that the Receiving Party or any of its Representatives (as the case may be), on advice of counsel, is required by Law to disclose and the Receiving Party and its Representatives use their respective reasonable best efforts (at the Disclosing Party's expense) to obtain assurances that confidential treatment will be accorded to such Confidential Information, Evaluation Material or Transaction Information, as applicable. Notwithstanding the foregoing, no such notice shall be required by the Receiving Party or any of its Representatives in connection with any routine audit or examination by a bank examiner or regulatory authority that is not in connection with, and does not reference, the Disclosing Party, a Transaction, Confidential Information, Evaluation Material, or Transaction Information. Notwithstanding any disclosure of Confidential Information, Evaluation Material or Transaction Information pursuant to this <u>Section 3</u>, the Receiving Party and its Representatives will continue to otherwise comply with the obligations of confidentiality and other obligations hereunder with respect to such Confidential Information, Evaluation Material or Transaction Information.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;4. You hereby agree that neither you nor any of your Representatives (acting for your or any of your affiliates' benefit, on your or any of your affiliates' behalf, or at your or any of your affiliates' direction) will have any discussions or other communications, or enter into any agreement, arrangement or understanding, whether formal or informal and whether or not binding, with any other prospective bidder for the Company with respect to (i) whether or not you or such other prospective bidder will make a bid or offer in connection with a Transaction or any other transaction involving the Company or any of its subsidiaries, or (ii) the price that you or such other bidder may bid or offer in connection with a Transaction or any other transaction involving the Company or any of its subsidiaries. You represent and warrant to the Company that, as of the date hereof, neither you nor any of your Representatives (acting for your benefit, on your benefit, or at your direction) have entered into any such agreement, arrangement or understanding.

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#### CONFIDENTIAL
 

<br> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;5.

You hereby agree that neither you nor any of your Representatives (acting for your or any of your affiliates' benefit, on your or any of your affiliates' behalf, or at your or any of your affiliates' direction) will, directly or indirectly, without the prior written consent of the Company, (a) contact any third party (other than an Approved Financing Source) who may participate with you in a Transaction, whether as a co-investor, strategic partner or otherwise, or who may provide debt or equity financing or other potential sources of capital in connection with a Transaction or any other transaction involving the Company or any of its subsidiaries to discuss a Transaction or any other transaction involving the Company or any of its subsidiaries in any manner whatsoever (including, without limitation, on a confidential or "no names" basis) or disclose any Confidential Information of the Company, any Evaluation Material derived therefrom, or any Transaction Information to any such third party, or (b) enter into any agreement, arrangement or understanding with any other person that has or would have the effect of requiring such person to provide you or any of your affiliates with equity or debt financing or other potential sources of capital on an exclusive basis in connection with a Transaction or any other transaction involving the Company or any of its subsidiaries, or that would have the effect of preventing, impairing or otherwise limiting the ability of any person to provide equity or debt financing or other potential sources of capital to any other person in connection with a Transaction or any other transaction involving the Company or any of its subsidiaries, whether or not such person becomes an Approved Financing Source. You represent and warrant to the Company that, as of the date hereof, neither you nor any of your Representatives (acting for your or any of your affiliates' benefit, on your or any of your affiliates' behalf, or at your or any of your affiliates' direction) have entered into any such agreement, arrangement or understanding. In addition, you hereby agree that you and your Representatives will not, directly or indirectly, discourage any financial institution or financial advisor from being retained by other bidders or potential bidders as advisors in connection with a Transaction or any other transaction involving the Company or any of its subsidiaries. You hereby agree that, if you or any of your Representatives are directly or indirectly contacted by a third party to discuss the possibility of participating with you in a Transaction, whether as a co-investor, strategic partner or otherwise, or the possibility of providing equity, debt or other type of financing for a Transaction, then you will promptly (and in any event within 24 hours) notify us of such contact (which notice will include, without limitation, the identity of the third party making such contact and the material terms and details of such discussions).

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6. You hereby agree that, without the prior written consent of the Company, all communications from you or your Representatives to the Company in connection with a Transaction, including requests for Confidential Information regarding the Company or any of its subsidiaries, will be submitted only to such person or persons as the Company may direct in writing and, unless expressly directed to the contrary by the Company, not to any other personnel of the Company or any of its Representatives. You agree that you and your Representatives will not engage in any discussions with the Company or any of its employees, customers, suppliers, vendors, service providers, joint venture partners, consultants, lenders, or other commercial or business counterparties in connection with a Transaction, or regarding any Transaction Information or Evaluation Material without the prior consent of the Company.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;7. You hereby agree that, except to the extent expressly authorized by the board of directors of the Company (or any authorized committee thereof) in advance, neither you nor any of your Representatives will directly or indirectly have any formal or informal discussions or other communications, or directly or indirectly enter into any agreement, arrangement or understanding, whether formal or informal and whether or not binding, with any director, officer or other employee of the Company or any of its subsidiaries relating to (a) any retention, severance or other compensation, incentives or benefits that may be or become payable to any directors, officers or employees of the Company or any of its subsidiaries in connection with a Transaction or following the consummation thereof, (b) any equity rollover or other similar transaction, or any equity or other investment in the Company or any parent company thereof, or any affiliate of the Company or any parent company thereof, following the consummation of a Transaction, or (c) any directorship, employment, consulting arrangement or other similar association or involvement of any directors, officers or other employees of the Company or any of its subsidiaries with the Company or any of its subsidiaries or any parent company thereof, or affiliate of the Company or any of its subsidiaries or any parent company thereof, following the consummation of a Transaction.

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<br> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.

Each party hereto hereby acknowledges that it is aware, and that it will advise its Representatives who are informed as to the matters which are the subject of this letter agreement, that the United States securities laws prohibit any person who has received from an issuer material, non-public information concerning the matters which are the subject of this letter agreement from purchasing or selling securities of such issuer or from communicating such information to any other person under circumstances in which it is reasonably foreseeable that such person is likely to purchase or sell such securities.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9. The Receiving Party hereby acknowledges and agrees that, other than those representations and warranties that may be made to the Receiving Party or its affiliates in a definitive written agreement with respect to a Transaction (when, as, and if executed, and subject to such limitations and restrictions as may be specified therein), none of the Disclosing Party or any of its Representatives have made or makes, and the Receiving Party and its Representatives have not relied upon and will not rely upon, any representation or warranty, express or implied, with respect to the business, operations, assets, financial performance, or prospects of the Disclosing Party or any of its subsidiaries, or any other matter, or as to the accuracy or completeness of any statement or information, including any Confidential Information of the Disclosing Party or any Evaluation Material derived therefrom. The Receiving Party hereby agrees that, except as may be expressly set forth in such definitive written agreement, none of the Disclosing Party or its Representatives will have any liability to the Receiving Party or any of its Representatives or any other person, including, without limitation, in contract, tort or under federal or state securities laws, relating to or resulting from the use of any Confidential Information of the Disclosing Party or any Evaluation Material derived therefrom by the Receiving Party or any of its Representatives or any errors therein or omissions therefrom, whether such Confidential Information or Evaluation Material is provided before or after entering into a definitive written agreement, and none of the Receiving Party or any of its Representatives will make any claims whatsoever with respect to or arising out of the Confidential Information of the Disclosing Party or for any errors therein or omissions therefrom. Each party acknowledges and agrees that its determination to engage in a Transaction, if any, will be based solely on the terms of such definitive written agreement and on such party's own investigation, analysis, and assessment of the other party and its affiliates. Nothing herein, nor any disclosure contemplated hereby, shall be deemed to transfer to the Receiving Party, any of its Representatives, or any other person any interest in, or confer in the Receiving Party or any other person any right (including, without limitation, intellectual property right) over, the Confidential Information of the Disclosing Party whatsoever beyond those interests and rights expressly provided for in this letter agreement. The Disclosing Party and its Representatives expressly disclaim any duty (express or implied) to update, supplement or correct any Confidential Information of the Disclosing Party disclosed under this letter agreement regardless of the circumstances.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10. Each party hereto hereby agrees that, unless and until a definitive written agreement between the Company and the Bidder (or their respective affiliates) with respect to a Transaction has been executed and delivered by each of the parties thereto, no party hereto will be under any legal obligation of any kind whatsoever with respect to a Transaction by virtue of this letter agreement or any written or oral expression with respect to a Transaction by any party hereto or any of its Representatives except, in the case of this letter agreement, for the matters specifically agreed to herein. Each party hereto hereby further acknowledges and agrees that (a) the other party or parties hereto shall have no obligation to authorize or pursue the Transaction, and (b) no party hereto has, as of the date hereof, authorized any Transaction. In addition, each party hereto acknowledges and agrees that the other party or parties hereto reserves the right, in its sole and absolute discretion, to reject any and all proposals made by such party or any of its Representatives with regard to a Transaction, to determine not to engage in discussions or negotiations and to terminate discussions and negotiations with such party or parties or with any other person at any time. You acknowledge and agree that the Company reserves the right to conduct, directly or through any of its Representatives, any process for any other transaction, if and as it in its sole discretion shall determine (including, without limitation, negotiating with any other interested parties and entering into a definitive agreement without prior notice to you or any other person).

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;11.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; The Disclosing Party may decide at any time to terminate further access by the Receiving Party to, and its review of, any Confidential Information of the Disclosing Party. Upon written request by the Disclosing Party, the Receiving Party and its Representatives will promptly (a) at the Receiving Party's option, deliver to the Disclosing Party or destroy all Confidential Information of the Disclosing Party, and (b) destroy all Evaluation Material derived from the Confidential Information of the Disclosing Party, in each case to the extent in the possession or control of the Receiving Party or any of its Representatives, and will not retain any copies, extracts or other reproductions in whole or in part of such Confidential Information or Evaluation Material (including, to the extent practicable, expunging all such Confidential Information and Evaluation Material from any computer, word processor or other device containing such information), *provided*, *however*, that notwithstanding the foregoing, (i) the Receiving Party and its Representatives may retain copies of any Confidential Information and Evaluation Material if and to the extent required by applicable Law, *provided* that such Confidential Information and Evaluation Material is not used for any purpose other than compliance with such Law, (ii) neither the Receiving Party nor any of its Representatives will be required to destroy any electronic copy of any Confidential Information or Evaluation Material which is retained pursuant to such person's bona fide document retention, electronic backup or archival procedures if (x) personnel whose functions are not primarily information technology in nature do not have access to such retained copies and (y) personnel whose functions are primarily information technology in nature have access to such copies only as reasonably necessary for the performance of their information technology duties (e.g., for purposes of system recovery), and (iii) if a legal proceeding has been instituted to seek disclosure of any Confidential Information or Evaluation Material, or that may otherwise implicate any such Confidential Information or Evaluation Material, such Confidential Information and Evaluation Material may be retained and need not be destroyed unless and until such legal proceeding is settled or a final judgment with respect thereto is rendered, *provided* that personnel whose functions are not primarily legal in nature or who otherwise are not directly involved in such legal proceeding do not have access to such retained copies. If requested by the Disclosing Party, an appropriate officer of the Receiving Party will certify to the Disclosing Party in writing that all such material has been so delivered or destroyed in compliance herewith. Regardless of the delivery or destruction of any Confidential Information or Evaluation Material required by this <u>Section 11</u>, any and all duties and obligations existing under this letter agreement with respect thereto will remain in full force and effect for so long as such information is retained by the Receiving Party or any of its Representatives notwithstanding the earlier termination of this letter agreement.

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;12. In consideration for being furnished with the Confidential Information relating to the Company and its subsidiaries, Bidder agrees that, during the Standstill Period (as defined below), none of Bidder, its affiliates, or any of their respective Representatives (acting for your or your affiliates' benefit, on your or your affiliates' behalf, or at your or your affiliates' direction) will in any manner, directly or indirectly, acting alone or as part of a group:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(a) acquire, agree to acquire, or publicly propose or offer to acquire, whether by means of a private or open market purchase, a block trade, a tender or exchange offer, a merger, consolidation or other form of business combination transaction or in any other manner, (i) beneficial ownership (as defined in Rule 13d-3 under the Exchange Act) of, any economic interest in, any right to direct the voting or disposition of, or any other right with respect to any securities of the Company or any of its subsidiaries, including through options, puts, calls, swaps or other derivative or convertible instruments, hedging contracts or any other form of transaction, agreement, arrangement or understanding (collectively, "<u>Derivative Securities</u>"), in each case, whether or not any of the foregoing may be acquired or obtained immediately or only after the passage of time or upon the satisfaction of one or more conditions (whether or not within the control of such party) and whether or not any of the foregoing would give rise to beneficial ownership (as defined under Rule 13d-3 under the Exchange Act), or (ii) ownership of any indebtedness, businesses, properties or assets of the Company or any of its subsidiaries, in each case including any rights or options to acquire such ownership through derivative or any other form of transaction;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(b) seek or attempt to effect, or publicly propose or offer to effect, (i) any merger, consolidation or other form of business combination transaction in each case with respect to or in any way involving the Company or any of its subsidiaries, (ii) any acquisition of stock or assets (whether by private or open market purchase, a block trade, a tender or exchange offer or any other form of transaction) in each case with respect to or in any way involving the Company or any of its subsidiaries, or (iii) any recapitalization, restructuring, liquidation, dissolution or any other extraordinary transaction, in each case with respect to or in any way involving the Company or any of its subsidiaries;

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(c) initiate, or induce or attempt to induce any other person or group to initiate, (i) any transaction of the type referenced in either of the foregoing clauses (a) and (b) of this <u>Section 12</u>, (ii) any stockholder proposal regarding the Company or any of its subsidiaries or any board of directors, management, business, strategies, policies or affairs thereof (whether binding or precatory in nature), or (iii) the calling, holding or convening of a stockholders' meeting of the Company for any purpose;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(d) &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(i) seek or attempt to change, control or influence, or induce or attempt to induce any other person or group to seek or attempt to change, control or influence, the board of directors, management, business, strategies, policies or affairs of the Company or any of its subsidiaries, or (ii) seek or attempt, or induce or attempt to induce any other person or group to seek or attempt, to obtain representation on the board of directors of the Company or any of its subsidiaries, including in each case, without limitation, by means of a "solicitation" of "proxies" (as such terms are defined in Rule 14a-1 of Regulation 14A promulgated pursuant to Section 14 of the Exchange Act, disregarding clause (iv) of Rule 14a-1(l)(2) and including any otherwise exempt solicitation pursuant to Rule 14a-2(b)), contacting any person relating to any of the matters set forth in this <u>Section 12</u> or seeking to influence, advise or direct the vote of any holder of voting securities of the Company or any of its subsidiaries;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(e) contact, or enter into any discussions or arrangements with, any person or group who has filed, or will (within ten (10) days thereafter) be required to file, a statement containing the information required by Rule 13d-1 under the Exchange Act, concerning any of the matters set forth in this <u>Section 12</u>;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(f) make any public announcement with respect to the restrictions of this <u>Section 12</u>, or take any action that might reasonably be expected to require the Company or its Representatives under applicable Law to make a public announcement regarding any of the matters referenced or described in this <u>Section 12</u>; or

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(g) advise, assist or encourage any other person or group (including serving as a financing source for any other person or group) in connection with any of the matters referenced or described in this <u>Section 12</u>.

The "<u>Standstill Period</u>" is the period commencing immediately after the execution of this letter agreement and ending (but only if Bidder is not in violation of this <u>Section 12</u>) upon the earliest to occur of: (i) 11:59 p.m., Pacific time, on the date that is one year after the date of this letter agreement; (ii) the date that any person other than Bidder or any of its affiliates has entered into a binding definitive agreement that has been duly approved by board of directors of the Company to acquire more than 50% of the outstanding voting securities of Company or assets of Company and its subsidiaries representing more than 50% of the consolidated earnings power of Company and its subsidiaries; or (iii) the date that Company files with the Securities and Exchange Commission a Schedule 14D-9 that does not recommend that Company's stockholders reject a tender or exchange offer commenced by a third person other than Bidder or any of its affiliates that, if consummated, would result in such person's acquisition of beneficial ownership of more than 50% of the outstanding voting securities of Company. For the avoidance of doubt, this <u>Section 12</u> will not restrict Bidder from making any proposal regarding a Transaction directly to the board of directors of the Company on a confidential basis, but only if such proposal would not reasonably be expected to require Company, Bidder, or another person to make a public announcement or other public statement regarding this letter agreement, such proposal, a Transaction or any of the matters described in this <u>Section 12</u>. You hereby represent and warrant that, as of the date of this letter agreement, neither you nor any of your affiliates possess any economic interest, voting right or other right with respect to any security (including Derivative Securities) of Company or any of its subsidiaries.

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#### CONFIDENTIAL
 

<br> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;13.

You hereby agree that, for a period of eighteen (18) months from the date of this letter agreement, none of you, your affiliates, or any of your or their Representatives (acting for your or your affiliate's benefit, on your or your affiliate's behalf, or at your or your affiliate's direction) will, directly or indirectly, solicit the employment or service of any individual who, during any period during which the parties are engaged in discussions regarding a Transaction, is a director, officer or employee of the Company or any of its subsidiaries; *provided*, *however*, that this letter agreement will not prohibit or otherwise restrict you from (i) publishing general advertisements or making general public solicitations (including through a third-party recruiting firm) for employment for any position not specifically targeted at any directors, officers, or employees of the Company or any of its subsidiaries, or (ii) hiring any director, officer, or employee of the Company or any of its subsidiaries who responds to an advertisement or general solicitation that is not specifically targeted at any directors, officers, employees of the Company or any of its subsidiaries.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;14. To the extent that any Confidential Information or Evaluation Materials may include material subject to the attorney-client privilege, work product doctrine or any other applicable privilege concerning pending or threatened legal or regulatory proceedings or governmental investigations, the parties hereto understand and agree that they have a commonality of interest with respect to such matters and it is their desire, intention and mutual understanding that the disclosure of such material is not intended to, and will not, waive or diminish in any way the confidentiality of such material or its continued protection under the attorney-client privilege, work product doctrine or other applicable privilege and any such Confidential Information and Evaluation Materials will remain entitled to all protection under these privileges, this letter agreement and the joint defense doctrine. Nothing in this letter agreement obligates any party hereto to reveal material subject to the attorney-client privilege, work product doctrine or any other applicable privilege, and in the event of an inadvertent disclosure of any materials which may have the effect of waiving any such privilege, the Receiving Party and its Representatives agree to destroy any such materials promptly upon the request of the Disclosing Party or its Representatives.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;15. Each party hereto hereby agrees to cause its Representatives to comply with the provisions of this letter agreement that apply to such party's Representatives and restrain from prohibited and unauthorized disclosure or use of the Confidential Information, Evaluation Material or Transaction Information, and further agrees that it will be responsible and liable for any actions taken or omissions made by any of such party's Representatives as if such actions were taken or such omissions made directly by such party hereto. The foregoing obligation shall not limit the remedies available to either party for any such breach of this letter agreement against any of the Representatives of the other party.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;16. This letter agreement and all obligations herein shall terminate on the third anniversary of the date of this letter agreement; *provided*, *however*, that <u>Sections 8</u> through <u>11</u>, inclusive, and <u>Sections 14</u> through <u>27</u>, inclusive, shall survive any termination of this letter agreement; *provided*, *further*, that this provision shall not relieve any party from liability for any breach of this letter agreement prior to such termination.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;17. Company acknowledges that you and your Representatives are in the investment business. Notwithstanding anything in this letter agreement to the contrary, this letter agreement shall not limit, restrict or impair the ability of you or your Representatives to engage in transactions with respect to securities of any entity other than the Company so long as such transactions would not violate applicable securities laws and to the extent that no Confidential Information, Transaction Information, or Evaluation Materials of the Company are used or disclosed in connection therewith. Company acknowledges and understands that you or your Representatives may now or in the future evaluate, invest in or do business with competitors or potential competitors of Company. Accordingly, nothing in this letter agreement will be construed as a representation or agreement that you or your Representatives will not continue to evaluate, invest in or do business with competitors or potential competitors of Company, and to the extent that no Confidential Information, Transaction Information, or Evaluation Materials of the Company are used or disclosed in connection therewith.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;18. Each party hereto hereby acknowledges and agrees that the other party hereto will be entitled to seek equitable relief (including, without limitation, injunction and specific performance) as a remedy for any breach or threatened breach of the terms of this letter agreement, and in furtherance thereof each party hereto further agrees (a) not to raise as a defense thereof that money damages would be an adequate remedy at law for any such breach or threatened breach or that any such breach or threatened breach should be compensable by an award of money damages and (b) to waive any requirements for the securing or posting of any bond in connection with such a remedy. Such remedies will not be deemed to be the exclusive remedies for a breach by a party or its Representatives of this letter agreement but shall be in addition to all other remedies available at law or equity to the other party.

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<br> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;19.

Except as expressly provided in this letter agreement or as may be contemplated by any definitive agreements, all costs and expenses incurred in connection with this letter agreement and the consideration, evaluation, negotiation and consummation by the parties of a Transaction, including, all fees of law firms, commercial banks, investment banks, accountants, public relations firms, experts and consultants, shall be paid by the party incurring such cost or expense.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;20. If any provision of this letter agreement is found to violate any statute, regulation, rule, order or decree of any governmental authority, court, agency or exchange, such invalidity shall not be deemed to affect any other provision hereof or the validity of the remainder of this letter agreement, and such invalid provision shall be deemed deleted herefrom to the minimum extent necessary to cure such violation.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;21. Each party hereby acknowledges and agrees that no failure or delay by the other party in exercising any right, power or privilege hereunder shall operate as a waiver thereof, nor will any single or partial exercise thereof preclude any other or further exercise thereof or the exercise of any other right, power or privilege hereunder.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;22. This letter agreement sets forth the entire agreement between the Bidder and the Company regarding the subject matter hereof and supersedes all prior agreements, understandings, arrangements and discussions between the Bidder and its Representatives and the Company and its Representatives regarding the subject matter hereof.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;23. This letter agreement may only be amended, modified or waived by a written instrument signed by you and the Company, which writing will only be effective to the extent that it expressly refers to the provision to be waived, modified or amended and sets forth the specific terms of such waiver, modification or amendment.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;24. This letter agreement will benefit and bind successors and assigns of the Bidder and the Company. Any assignment of this letter agreement by either party hereto without the prior written consent of the other party will be void and of no effect, except that the Company may assign this letter agreement without the prior consent of Bidder to any acquiror of the Company or a majority of its voting securities or consolidated assets. This letter agreement is intended to be for the benefit of each party hereto and its affiliates and Representatives.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;25. This letter agreement, and all claims, causes of action (whether in contract, tort or statute) or other matter that may result from, arise out of, be in connection with or relating to this letter agreement or the negotiation, administration, performance, or enforcement of this letter agreement (collectively, "<u>Relevant Matters</u>"), is governed by, and construed in accordance with, the laws of the State of Delaware (including its statute of limitations) without regard to conflict of laws principles or other principle that would apply the laws of any other jurisdiction. Each party irrevocably submits to the jurisdiction of the Court of Chancery of the State of Delaware and any state appellate court therefrom within the State of Delaware (or, if the Court of Chancery of the State of Delaware declines to accept jurisdiction over a particular matter, any state or federal court within the State of Delaware) for purposes of any action, suit, or proceeding resulting from, arising out of, that is in connection with, or relating to any Relevant Matter. Each party irrevocably and unconditionally waives (and agrees not to plead or claim) any objection to the laying of venue of any such action, suit or proceeding in the Court of Chancery of the State of Delaware and any state appellate court therefrom within the State of Delaware (or, if the Court of Chancery of the State of Delaware declines to accept jurisdiction over a particular matter, any state or federal court within the State of Delaware) or that any such action, suit or proceeding brought in any such court has been brought in an inconvenient forum. EACH PARTY HERETO IRREVOCABLY WAIVES ANY AND ALL RIGHT TO TRIAL BY JURY IN ANY ACTION, SUIT, OR PROCEEDING RESULTING FROM, ARISING OUT OF, THAT IS IN CONNECTION WITH, OR RELATING TO ANY RELEVANT MATTER.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;26. This letter agreement also applies to any Confidential Information accessed through the Company's electronic data room and supersedes any "click through" acknowledgement or agreement associated with any such electronic data room.

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<br> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;27.

This letter agreement may be signed by .pdf or other electronic means and in one or more counterparts, each of which shall be deemed an original but all of which shall be deemed to constitute a single instrument.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;27. This letter agreement also constitutes notice to you that Company has engaged Wilson Sonsini Goodrich & Rosati, Professional Corporation ("<u>Wilson Sonsini</u>") as its legal counsel in connection with a Transaction. You (i) consent to Company's representation by Wilson Sonsini in connection with this letter agreement and a Transaction notwithstanding that Wilson Sonsini may have represented, and may currently or in the future represent, you or any of your affiliates with respect to unrelated matters; and (ii) waive any actual or alleged conflict or actual or alleged violation of ethical or comparable rules applicable to Wilson Sonsini that may arise from its representation of Company in connection with this letter agreement and a Transaction. In addition, you acknowledge and agree that (A) the consent and waiver pursuant to this <u>Section</u> <u>27</u> is voluntary and informed; (B) you are aware of the extent of your relationships, if any, with Wilson Sonsini; and (C) you do not require additional information from Wilson Sonsini in order to understand the nature of this consent. Wilson Sonsini is an express third-party beneficiary of this <u>Section</u> <u>27</u>.

*[Remainder of Page Intentionally Left Blank]*

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If you are in agreement with the foregoing, please so indicate by signing and returning one copy of this letter agreement, whereupon this letter agreement will constitute our binding agreement with respect to the subject matter hereof.

---

| | |
|:---|:---|
| Very truly yours, | Very truly yours, |
| **IGM BIOSCIENCES, INC.** | **IGM BIOSCIENCES, INC.** |
| By: | /s/ Dr. Mary Beth Harler |
| Name: | Dr. Mary Beth Harler |
| Title: | Chief Executive Officer |

---

---

| | |
|:---|:---|
| **CONFIRMED, ACCEPTED AND AGREED**: | **CONFIRMED, ACCEPTED AND AGREED**: |
| **CONCENTRA BIOSCIENCES, LLC** | **CONCENTRA BIOSCIENCES, LLC** |
| By: | /s/ Kevin Tang |
| Name: | Kevin Tang |
| Title: | Chief Executive Officer |

---

[Signature Page to Confidentiality Agreement] <br>

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## Ex-99.(D)(3)

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#### 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., a Delaware corporation (the "***Company***") and the Representative to be party to the CVR Agreement (as defined below) (the "***Representative***"). Reference is hereby made to (i) that certain Agreement and Plan of Merger, dated as of the date hereof (the "***Merger Agreement***"), by and among Concentra Biosciences, LLC, a Delaware limited liability company ("***Parent***"), Concentra Merger Sub V, Inc., a Delaware corporation and a wholly owned subsidiary of Parent ("***Merger Sub***") and the Company, pursuant to which, among other things, Merger Sub will merge with and into the Company with the Company continuing as the surviving corporation in the merger as a wholly owned subsidiary of Parent, on the terms and subject to the conditions set forth in the Merger Agreement and (ii) that certain Contingent Value Rights Agreement (the "***CVR Agreement***") to be entered into in accordance with the Merger Agreement by and among Parent, Merger Sub, the Rights Agent (as defined in the CVR Agreement) and the Representative. As used in this Limited Guaranty, references to the "***Guaranteed Party***" shall mean (i) the Company with respect to the Guaranteed Purchase Price Obligation and the Guaranteed Damages Obligation and (ii) the Representative with respect to the Guaranteed CVR Obligation. Capitalized terms used herein but not otherwise defined herein have the meanings ascribed to them in the Merger Agreement or the CVR Agreement.

1. <u>Limited Guaranty</u>.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(a) To induce the Guaranteed Party to enter into the Merger Agreement and the CVR Agreement, the Guarantor, intending to be legally bound, hereby expressly, absolutely, irrevocably and unconditionally guarantees to the Guaranteed Party, subject to the terms and conditions hereof:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(i) With respect to the Company as the Guaranteed Party: (A) the obligation to promptly fund all amounts payable by Parent and/or Merger Sub pursuant to the terms of the Merger Agreement in connection with consummation of the transactions contemplated thereby (for the avoidance of doubt, such obligations shall include payment of Offer Price, the Merger Consideration, the Company Stock Option Cash Consideration and the Restricted Stock Unit Cash Consideration, without duplication) (collectively, the "***Guaranteed Purchase Price Obligation***"); and (B) the obligation of Parent and/or Merger Sub to pay monetary damages to the Guaranteed Party in connection with fraud or a Willful Breach by Parent or Merger Sub of the Merger Agreement pursuant to a final non-appealable judgment by a court of competent jurisdiction in accordance with Section 9.02 of the Merger Agreement, together with any Enforcement Costs (collectively, the "***Guaranteed Damages Obligation***"); provided that the maximum amount of the Guaranteed Purchase Price Obligation plus the Guaranteed Damages Obligation shall not exceed $78,000,000 (the "***Maximum Guaranteed Purchase Obligations***"); and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(ii) With respect to the Representative as the Guaranteed Party: the payment obligations of Parent and Merger Sub and to perform the covenants set forth in the CVR Agreement, including to pay the aggregate CVR Payment Amount (as defined in the CVR Agreement), together with any Enforcement Costs, in each case under and in accordance with the terms, conditions and limitations of the CVR Agreement, subject to, in the case of any such Enforcement Costs payable under the CVR Agreement, the CVR Expense Cap (as defined in the CVR Agreement) (collectively, the "***Guaranteed CVR Obligation***", and, together with the Guaranteed Purchase Price Obligation and the Guaranteed Damages Obligation, the "***Guaranteed Obligations***"), provided that the maximum amount of the Guaranteed CVR Obligation shall not exceed the CVR Proceeds plus all such Enforcement Costs up to the CVR Expense Cap (the "***Maximum CVR Obligation***" and, together with the Maximum Guaranteed Purchase Obligation, the "***Maximum Guaranteed Obligations***").

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(b) The Guaranteed Purchase Price Obligation shall be reduced on a dollar-for-dollar basis by the amount that such obligation is actually satisfied by Parent or Merger Sub, as applicable, and the Guaranteed CVR Payment Obligation and Guaranteed Damages Obligation shall be reduced on a dollar-for-dollar basis by the amount that any such obligation is actually satisfied by Parent, Merger Sub or the Company, as applicable.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(c) Notwithstanding anything herein to the contrary, the Guaranteed Party hereby agrees that (i) in no event will the Guarantor be required to pay to any Person or Persons more than the Maximum Guaranteed Obligations, in respect of or in connection with this Limited Guaranty, the Merger Agreement, the CVR Agreement or any other document or instrument delivered in connection herewith or therewith ("***Transaction Documents***"), or the transactions contemplated hereby or thereby (or the termination or abandonment thereof) or otherwise ("***Transactions***"), and (ii) the Guarantor shall not have any obligation or liability to any Person or Persons (including, without limitation, to the Holders (as defined in the CVR Agreement), Affiliates and subsidiaries) relating to, arising out of or in connection with the Transaction Documents or the Transactions, other than as expressly set forth herein and solely to the extent hereof. Notwithstanding anything to the contrary contained in the Transaction Documents, the Guaranteed Party hereby agrees that to the extent Parent, Merger Sub or the Company is relieved of all or any portion of its payment or performance obligations under the Merger Agreement or CVR Agreement, by satisfaction or waiver thereof or pursuant to any other agreement with the Guaranteed Party, the Guarantor shall be similarly relieved, to such extent, of their respective obligations under this Limited Guaranty.

2. <u>Terms of Limited Guaranty</u>.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(a) This Limited Guaranty is an absolute, unconditional, irrevocable and continuing guarantee of payment, not of collection, and a separate action may be brought and prosecuted against the Guarantor to enforce this Limited Guaranty, irrespective of whether any action is brought against Parent or Merger Sub or whether Parent or Merger Sub are joined in any action, up to an amount equal to the Maximum Guaranteed Obligations. All payments to be made hereunder by the Guarantor shall be made in United States Dollars.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(b) The liability of the Guarantor under this Limited Guaranty shall, to the fullest extent permitted under Applicable Law and to the extent provided herein, be absolute, irrevocable and unconditional, other than as provided herein.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(c) The Guarantor hereby waives any and all notice of the creation, renewal, extension or accrual of any of the Guaranteed Obligations and notice of or proof of reliance by the Guaranteed Party upon this Limited Guaranty or acceptance of this Limited Guaranty. Without expanding the obligations of the Guarantor hereunder, the Guaranteed Obligations shall conclusively be deemed to have been created, contracted or incurred in reliance upon this Limited Guaranty, and all dealings between Parent, Merger Sub, the Company and/or the Guarantor, on the one hand, and the Guaranteed Party, on the other, shall likewise be conclusively presumed to have been had or consummated in reliance upon this Limited Guaranty. This Limited Guaranty is a primary obligation of the Guarantor and not merely the creation of a surety relationship. When pursuing any of its rights and remedies hereunder against the Guarantor, the Guaranteed Party shall be under no obligation to pursue (or elect among) such rights and remedies they may have against Parent, Merger Sub, or the Company or any other Person for the Guaranteed Obligations or any right of offset with respect thereto, and any failure by the Guaranteed Party to pursue such other rights or remedies or to collect any payments from Parent, Merger Sub, or the Company or any such other Person or to realize upon or to exercise any such right of offset shall not relieve the Guarantor of any liability hereunder.

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(d) The Guaranteed Party shall not be obligated to file any claim relating to any Guaranteed Obligation in the event that Parent, Merger Sub or the Company becomes subject to a bankruptcy, insolvency, reorganization or similar proceeding, and the failure of the Guaranteed Party to so file shall not affect the Guarantor's obligation hereunder (and notwithstanding anything herein to the contrary, any bar to the payment, or collection, of any Guaranteed Obligations as a result of any such proceeding shall not discharge the obligations of the Guarantor hereunder).

3. <u>Sole Remedy; No Recourse</u>. Notwithstanding anything that may be expressed or implied in this Limited Guaranty or any document or instrument delivered in connection herewith, by its acceptance of the benefits of this Limited Guaranty, for so long as this Limited Guaranty is in effect, the Guaranteed Party further agrees that, except for: (a) the Guaranteed Party's rights against the Guarantor under this Limited Guaranty; (b) the Guaranteed Party's remedies against Parent and Merger Sub and the Company and their assignees under the Merger Agreement and CVR Agreement; and (c) remedies against the Guarantor under the Confidentiality Agreement (collectively, the "***Permitted Claims***"), neither the Guaranteed Party nor any other Person (including, without limitation, the Holders (as defined in the CVR Agreement) and the Guaranteed Party's and the Holders' respective Affiliates and subsidiaries) has any right of recovery against, and no personal liability shall attach to, the Guarantor, any former, current or future, direct or indirect director, officer, employee, agent or Affiliate of the Guarantor, any former, current or future, direct or indirect holder of any equity interests or securities of the Guarantor (whether such holder is a limited or general partner, member, manager, stockholder or otherwise), any former, current or future assignee of the Guarantor, or any former, current or future director, officer, employee, agent, general or limited partner, manager, member, stockholder, Affiliate, controlling person, representative or assignee of any of the foregoing (each such Person, a "***Related Person***"), relating to, arising out of, or in connection with the Transaction Documents or the Transactions, through Parent, Merger Sub, the Company or otherwise, whether by or through attempted piercing of the corporate, limited liability company or limited partnership veil, by or through a claim by or on behalf of Parent against the Guarantor or any Related Person. The Permitted Claims shall be the sole and exclusive remedies of the Guaranteed Party, the Holders and all of their respective Affiliates and subsidiaries against the Guarantor and its Related Persons in respect of any liabilities or obligations relating to, arising out of, or in connection with, the Transaction Documents or the Transactions, including by or through attempted piercing of the corporate veil or similar action, by the enforcement of any assessment or by any proceeding at law or equity by or on behalf of Parent, Merger Sub or the Company. The Guaranteed Party hereby covenants and agrees that the Guaranteed Party shall not institute and shall cause its controlled Affiliates and subsidiaries not to institute, any proceeding or bring any other claim arising under, or in connection with, the Transaction Documents or the Transactions, against the Guarantor or its Related Persons, except for the Permitted Claims by or on behalf of the Guaranteed Party and its respective controlled Affiliates and subsidiaries, and the Guaranteed Party waives any and all claims arising under, or in connection with, the Transaction Documents or the Confidentiality Agreement or, in each case, the transactions contemplated hereby or thereby against the Guarantor or its respective Related Persons and release such Persons from such claims, in each case, except for Permitted Claims. Nothing set forth in this Limited Guaranty shall affect or be construed to affect any liability of Parent, Merger Sub or the Company or shall confer or give, or shall be construed to confer or give, to any Person (including any Person acting in a representative capacity or any equity holder of the Guaranteed Party) other than the Guaranteed Party any rights or remedies against any Person, including the Guarantor, except as expressly set forth herein.

4. <u>Subrogation</u>. The Guarantor hereby unconditionally and irrevocably waives, and agrees that it will not exercise against Parent, Merger Sub or the Company any rights of subrogation or contribution, whether arising by contract or operation of law (including, without limitation, any such right arising under bankruptcy or insolvency laws) or otherwise, by reason of any payment by it pursuant to the provisions of <u>Section 1</u> hereof unless and until the Guaranteed Obligations have been paid in full.

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5. <u>Termination</u>. This Limited Guaranty shall automatically and immediately terminate (and the Guarantor shall have no further obligations hereunder): (a) with respect to the Guaranteed Purchase Price Obligation, upon the earliest to occur of (i) the Merger Closing Date (and payment in full of all amounts required to be paid under Section 3.09(a) of the Merger Agreement), (ii) the payment in full of the Guaranteed Purchase Price Obligation or (iii) the valid termination of the Merger Agreement in accordance with its terms; provided, however, that, for the avoidance of doubt, any purported termination of the Merger Agreement that is not a valid termination shall not give rise to a termination of this Limited Guaranty pursuant to this <u>Section 5</u>; (b) with respect to the Guaranteed CVR Obligation, upon the earliest to occur of (i) the payment in full of the Guaranteed CVR Obligation or (ii) the valid termination of the CVR Agreement in accordance with its terms; and (c) with respect to the Guaranteed Damages Obligation, upon termination of the Merger Agreement in accordance with its terms (other than a termination if and to the extent that no later than the 90th day immediately following such termination, the Company shall have commenced a Proceeding against Parent or Merger Sub in a court of competent jurisdiction seeking monetary damages for fraud or a Willful Breach of the Merger Agreement by Parent or Merger Sub arising prior to termination thereof, in which case this Limited Guaranty, and the obligations and liability of the Guarantor hereunder, in respect of the Guaranteed Damages Obligation shall terminate no later than the earlier of the final adjudication of such claim after which no further appeal may be taken or the written agreement of the parties in settlement of such claim and terminating such Proceeding). In the event that prior to the Merger Closing Date the Guaranteed Party expressly asserts, on behalf of any of its controlled Affiliates or subsidiaries, in any litigation or other legal proceeding relating to this Limited Guaranty (i) that the provisions hereof (including, without limitation, <u>Section 1</u> hereof limiting the Guarantor's aggregate liability to the Maximum Guaranteed Obligations or <u>Section 3</u> hereof relating to the sole and exclusive remedies of the Guaranteed Party, the Holders (as defined in the CVR Agreement) and their respective Affiliates and subsidiaries against the Guarantor or its Related Persons) are illegal, invalid or unenforceable, in whole or in part, or (ii) any theory of liability against the Guarantor or its Related Persons other than any Permitted Claim, then (A) the obligations of the Guarantor under this Limited Guaranty shall terminate ab initio and be null and void, (B) if the Guarantor has previously made any payments under this Limited Guaranty, the Guarantor shall be entitled to recover such payments from the Guaranteed Party and (C) neither the Guarantor nor its Related Persons shall have any liability to the Guaranteed Party, the Holders or any of their respective Affiliates or subsidiaries with respect to this Limited Guaranty.

6. <u>Entire Agreement</u>. The Transaction Documents and the Confidentiality Agreement constitute the entire agreement with respect to the subject matter hereof, and supersede all other prior agreements and understandings, both written and oral, among Parent, Merger Sub, the Company and/or the Guarantor or any of their respective Affiliates, on the one hand, and the Guaranteed Party or any of its Affiliates, on the other hand, and this Limited Guaranty is not intended to and shall not confer upon any Person (including, without limitation, the Holders (as defined in the CVR Agreement) and the Guaranteed Party's and the Holders' respective Affiliates and subsidiaries) other than the parties hereto, or any Related Person any rights or remedies. Except as expressly provided in this Limited Guaranty, no representation or warranty has been made or relied upon by any of the parties to this Limited Guaranty with respect to this Limited Guaranty.

7. <u>Acknowledgement</u>. The Guarantor hereby acknowledges and agrees that the Guarantor will not willfully and intentionally circumvent the payment mechanics under the CVR Agreement by taking dividends, distributions or payments from the Company using proceeds that should otherwise inure to the benefit of the Holders (as defined in the CVR Agreement). For the avoidance of doubt, until termination of the Guaranteed CVR Obligation, and subject to Section 8, the Guaranteed Party shall be entitled to enforce the Guarantor's obligation under this Section 7.

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8. <u>Third-Party Beneficiaries</u>. The Guarantor and the Guaranteed Party hereby agree that the covenants and agreements set forth herein solely with respect of the Guaranteed CVR Obligations, are intended to be for the benefit of all Holders (as defined in the CVR Agreement) and shall be enforceable by the Representative. The Representative, solely at the direction of and with the prior written consent of the Acting Holders (as defined in the CVR Agreement), will have the right, on behalf of all Holders, by virtue of or under any provision of this Limited Guaranty relating to the Guaranteed CVR Obligations, to institute any action or proceeding at law or in equity or in bankruptcy or otherwise upon or under or with respect to the Guaranteed CVR Obligations set forth in this Limited Guaranty, and no other Person or Persons will be entitled to exercise such rights. For avoidance of doubt and notwithstanding anything to the contrary herein, the Representative shall not commence any action under this Limited Guaranty on behalf of or to enforce the rights of the Holders except at the direction of and with the prior written consent of the Acting Holders.

9. <u>Amendments and Waivers</u>. Any provision of this Limited Guaranty may be amended or waived only in a writing signed by the Guarantor and the Guaranteed Party. No waiver by any party of any breach or violation of, or default under, this Limited Guaranty, whether intentional or not, will be deemed to extend to any prior or subsequent breach, violation or default hereunder or affect in any way any rights arising by virtue of any prior or subsequent such occurrence. No delay or omission on the part of any party in exercising any right, power or remedy under this Limited Guaranty will operate as a waiver thereof.

10. <u>Notices</u>. Any notice, request, or demand desired or required to be given hereunder will be in writing and will be given by email delivery, addressed as respectively set forth below or to such email address as any party hereto will have previously designated by such a notice. The effective date of any notice, request, or demand will be the date on which the email is sent (provided that the sender of such email does not receive a written notification of delivery failure).

<u>Notices to the Guarantor, Parent or Merger Sub:</u>

Concentra Biosciences, LLC

4747 Executive Dr. Suite 210

San Diego, California 92121

Attention: Kevin Tang

Email: [\*\*\*]

<u>with a copy to (which shall not constitute notice):</u>

Gibson, Dunn & Crutcher LLP

One Embarcadero Center, Suite 2600

San Francisco, California 94111-3715

Attention: Ryan A. Murr

Email: rmurr@gibsondunn.com

<u>Notices to the Guaranteed Party:</u>

IGM Biosciences, Inc.

325 E. Middlefield Road

Mountain View, California 94043

Attention: Misbah Tahir

Email: [\*\*\*]

<u>with a copy (which shall not constitute notice) to:</u>

Wilson Sonsini Goodrich & Rosati, P.C.

650 Page Mill Road

Palo Alto, California 94304

Attention: Robert Ishii; Ethan Lutske

Email: rishii@wsgr.com; elutske@wsgr.com

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11. <u>Governing Law</u>. The provisions of Sections 10.06 (Governing Law), 10.08(b) (Jurisdiction) and 10.09 (Waiver of Jury Trial) of the Merger Agreement are hereby incorporated herein by reference, *mutatis mutandis*.

12. <u>Representations and Warranties</u>. The Guarantor hereby represents and warrants to the Guaranteed Party that: (a) it has all limited partnership, corporate or other organizational power and authority to execute, deliver and perform this Limited Guaranty; (b) the execution, delivery and performance of this Limited Guaranty by it has been duly and validly authorized and approved by all necessary limited partnership, corporate or other organizational action by it; (c) this Limited Guaranty has been duly and validly executed and delivered by it and constitutes a valid and legally binding obligation of it, enforceable against it in accordance with the terms of this Limited Guaranty; (d) it has, and will have at all times prior to the termination of this Limited Guaranty, available funds in excess of the sum of Maximum Guaranteed Obligations plus the aggregate amount of all other commitments and obligations it currently has outstanding; (e) if applicable, all consents, approvals, authorizations, permits of, filings with and notifications to, any Governmental Entity necessary for the due execution, delivery and performance of this Limited Guaranty by it have been obtained or made and all conditions thereof have been duly complied with, and no other action by, and no notice to or filing with, any Governmental Entity or regulatory body is required in connection with the execution, delivery or performance of this Limited Guaranty; and (f) the execution, delivery and performance by the Guarantor of this Limited Guaranty do not and will not (i) conflict with or result in any violation of or contravene the organizational documents of the Guarantor, (ii) violate any applicable Law, rule, regulation, decree, order or judgment binding on the Guarantor or its assets, or (iii) result in any violation of, or default (with or without notice or lapse of time or both) under, or give rise to a right of termination, cancellation or acceleration of any obligation or to the loss of any benefit under, any contract or agreement to which the Guarantor is a party.

13. <u>No Assignment</u>. Neither this Limited Guaranty nor any of the rights, interests or obligations hereunder shall be assignable without the prior written consent of the Guaranteed Party (in the case of an assignment by the Guarantor) or the Guarantor (in the case of an assignment by any of the Guaranteed Party) and any attempted assignment without such required consents shall be null and void and of no force or effect. Subject to the foregoing, all of the terms and provisions of this Limited Guaranty shall inure to the benefit of and be binding upon the parties hereto and their respective successors and permitted assigns.

14. <u>Severability</u>. If any term or other provision of this Limited Guaranty is determined by a court of competent jurisdiction to be invalid, illegal or incapable of being enforced by any rule or law, or public policy, all other conditions and provisions of this Limited Guaranty shall nevertheless remain in full force and effect. Upon such determination that any term or other provision is invalid, illegal or incapable of being enforced, the parties hereto shall negotiate in good faith to modify this Limited Guaranty so as to effect the original intent of the parties hereto as closely as possible in an acceptable manner to the end that the transactions contemplated hereunder are fulfilled to the extent possible.

15. <u>Headings</u>. The headings contained in this Limited Guaranty are for reference purposes only and shall not affect in any way the meaning or interpretation of this Limited Guaranty.

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16. <u>Counterparts</u>. This Limited Guaranty may be executed in any number of counterparts, each of which will be deemed an original, but all of which together will constitute one and the same instrument. This Limited Guaranty will become effective when duly executed by each party hereto.

*[Remainder of page intentionally left blank]*

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IN WITNESS WHEREOF, the undersigned have caused this Limited Guaranty to be executed and delivered as of the date first written above.

Concentra Biosciences, LLC, as Parent

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| | |
|:---|:---|
| By: | /s/ Kevin Tang |
| Name: | Kevin Tang |
| Title: | Chief Executive Officer |

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Concentra Merger Sub V, Inc., as Merger Sub

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| | |
|:---|:---|
| By: | /s/ Kevin Tang |
| Name: | Kevin Tang |
| Title: | Chief Executive Officer |

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Tang Capital Partners, LP, as Guarantor

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| | |
|:---|:---|
| By: | /s/ Kevin Tang |
| Name: | Kevin Tang |
| Title: | President of Tang Capital Management, LLC, General Partner |

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[Signature Page to Limited Guaranty]

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IN WITNESS WHEREOF, the undersigned have caused this Limited Guaranty to be executed and delivered as of the date first written above.

IGM Biosciences, Inc., as Guaranteed Party

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| | |
|:---|:---|
| By: | /s/ Mary Beth Harler, M.D. |
| Name: | Mary Beth Harler, M.D. |
| Title: | Chief Executive Officer |

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[Signature Page to Limited Guaranty]

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## Ex-Filing

#### Exhibit 107<br>

#### <br>

#### 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

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| | | | |
|:---|:---|:---|:---|
| | Transaction<br> Valuation\* | Fee<br> Rate | Amount of<br> Filing Fee\*\* |
|  Fees to Be Paid | $83997829.98 | 0.00015310 | $12860.07 |
|  Fees Previously Paid | $0.00 |  | $0.00 |
|  **Total Transaction Valuation** | $83997829.98 |  |  |
|  **Total Fees Due for Filing** |  |  | $12860.07 |
|  **Total Fees Previously Paid** |  |  | $0.00 |
|  **Total Fee Offsets** |  |  | $0.00 |
|  **Net Fee Due** |  |  | $12860.07 |

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\* The transaction valuation is estimated for purposes of calculating the amount of the filing fee only. The transaction valuation was estimated by adding: (i) the product of (A) the sum of (1) 60,189,151 shares of common stock (34,802,168 shares of voting common stock and 25,386,983 shares of non-voting common stock), par value $0.01 per share (the "Shares") of IGM Biosciences, Inc. ("IGM"), issued and outstanding; (2) 1,030,014 Shares subject to outstanding restricted stock units; and (B) $1.3425, the average of the high and low sales prices per Share on July 9, 2025, as reported by the Nasdaq Stock Market LLC (which, for the purposes of calculating the filing fee only, shall be deemed to be the "Reference Price"); (ii) the product of (A) 96,328, the number of Shares issuable upon the exercise of in-the-money stock options; and (B) $0.3437, the difference between the Reference Price and $0.9988, the weighted average exercise price of such options; and (iii) the product of (A) 1,334,332, the number of Shares issuable upon the exercise of pre-funded warrants; and (B) $1.3325, the difference between the Reference Price and $0.01, the weighted average exercise price of such pre-funded warrants. All Share amounts are based on information provided by IGM as of June 27, 2025.

\*\* The amount of the filing fee was calculated in accordance with Rule 0-11 of the Securities Exchange Act of 1934, as amended, and Fee Rate Advisory #1 for fiscal year 2025 beginning on October 1, 2024, issued on August 20, 2024, by multiplying the transaction valuation by 0.00015310.

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