| Item 1. | |
| (a) | Name of issuer:
C4 Therapeutics, Inc. |
| (b) | Address of issuer's principal executive offices:
490 Arsenal Way, Suite 120, Watertown, Massachusetts 02472 |
| Item 2. | |
| (a) | Name of person filing:
This Schedule 13G is being filed jointly by Bain Capital Life Sciences Fund II, L.P., a Cayman Islands exempted limited partnership ("BCLS Fund II"), BCIP Life Sciences Associates, LP, a Delaware limited partnership ("BCIPLS"), and BCLS II Equity Opportunities, LP, a Delaware limited partnership ("BCLS II Equity" and, together with BCLS Fund II and BCIPLS, the "Reporting Persons").
Bain Capital Life Sciences Investors, LLC, a Delaware limited liability company ("BCLSI"), is the manager of Bain Capital Life Sciences Investors II, LLC, a Cayman Islands limited liability company ("BCLSI II"), which is the general partner of BCLS Fund II.
Boylston Coinvestors, LLC, a Delaware limited liability company ("Boylston"), is the general partner of BCIPLS. BCLSI governs the investment strategy and decision-making process with respect to investments held by BCIPLS.
BCLS II Equity Opportunities GP, LLC, a Delaware limited liability company ("BCLS II Equity GP" and, together with the Reporting Persons, BCLSI, BCLSI II and Boylston, the "Bain Capital Life Sciences Entities"), whose manager is BCLS Fund II, is the general partner of BCLS II Equity.
As a result, BCLSI may be deemed to share voting and dispositive power with respect to the securities held by the Reporting Persons.
The Reporting Persons have entered into a Joint Filing Agreement, dated October 24, 2025, pursuant to which the Reporting Persons have agreed to file this Schedule 13G jointly in accordance with the provisions of Rule 13d-1(k)(1) promulgated under the Act. |
| (b) | Address or principal business office or, if none, residence:
The principal business address for each of the Bain Capital Life Sciences Entities is 200 Clarendon Street, Boston, Massachusetts 02116. |
| (c) | Citizenship:
See Item 2(a) hereof. |
| (d) | Title of class of securities:
Common Stock, par value $0.0001 per share |
| (e) | CUSIP No.:
12529R107 |
| Item 3. | If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a: |
| (a) |  Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
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| (b) | Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
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| (c) | Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
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| (d) | Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
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| (e) | An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
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| (f) | An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
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| (g) | A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
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| (h) | A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
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| (i) | A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
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| (j) | A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J),
please specify the type of institution:
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| (k) | Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
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| | |
| Item 4. | Ownership |
| (a) | Amount beneficially owned:
As of the date hereof, (i) BCLS Fund II holds 991,188 shares of Common Stock; (ii) BCIPLS holds 120,722 shares of Common Stock; and (iii) BCLS II Equity holds 2,020,000 shares of Common Stock and warrants to purchase an aggregate of 4,040,000 Common Stock. As a result of the foregoing and the relationships described in Item 2(a), the Reporting Persons may be deemed to collectively beneficially own an aggregate of 7,171,910 shares of Common Stock, representing approximately 7.4% of the outstanding Common Stock. BCLS II Equity is prohibited from exercising the warrants to purchase Common Stock if, as a result of such exercise, the Reporting Persons would beneficially own more than 9.99% of the total number of shares of Common Stock then issued and outstanding immediately after giving effect to the exercise.
The calculation of the beneficial ownership of the Reporting Persons is based on (i) 92,902,083 shares of Common Stock outstanding, as reported by the Issuer in its prospectus supplement filed with the Securities and Exchange Commission on October 16, 2025 and (ii) 4,040,000 shares of Common Stock issuable upon the exercise of warrants held by BCLS II Equity. |
| (b) | Percent of class:
See Item 4(a) hereof. |
| (c) | Number of shares as to which the person has:
|
| | (i) Sole power to vote or to direct the vote:
0
|
| | (ii) Shared power to vote or to direct the vote:
See Item 4(a) hereof.
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| | (iii) Sole power to dispose or to direct the disposition of:
0
|
| | (iv) Shared power to dispose or to direct the disposition of:
See Item 4(a) hereof.
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| Item 5. | Ownership of 5 Percent or Less of a Class. |
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| Item 6. | Ownership of more than 5 Percent on Behalf of Another Person. |
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Not Applicable
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| Item 7. | Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person. |
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Not Applicable
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| Item 8. | Identification and Classification of Members of the Group. |
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Not Applicable
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| Item 9. | Notice of Dissolution of Group. |
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Not Applicable
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Rule 13d-1(c)