SCHEDULE 13G/A 0001812275 XXXXXXXX LIVE 2 Common Stock, par value $0.0001 per share 12/31/2025 0001662579 C4 Therapeutics, Inc 12529R107 490 Arsenal Way Suite 120 Watertown MA 02472 Rule 13d-1(c) Soleus Private Equity Fund III, L.P. DE 0.00 6072822.00 0.00 6072822.00 6072822.00 N 5.9 PN (1) The shares reported in the table above are held directly by Soleus Private Equity Fund III, L.P. ("Soleus PE"). Soleus Private Equity GP III, LLC ("Soleus PE GP") is the sole general partner of Soleus PE, Soleus PE GP III, LLC is the sole manager of Soleus PE GP, Soleus Capital Management, L.P. ("SCM") is the investment manager for Soleus PE and for Soleus Capital Master Fund, L.P. ("Master Fund"), and Soleus GP, LLC is the sole general partner of SCM. Guy Levy is the sole managing member of each of Soleus PE GP III, LLC and of Soleus GP, LLC. Each of Mr. Levy, Soleus PE GP III, LLC, Soleus PE GP, SCM and Soleus GP, LLC disclaims beneficial ownership of these shares held by Soleus PE other than for the purpose of determining their obligations under Section 13(d) of the Securities Exchange Act of 1934, as amended (the "Exchange Act"), and the filing of this report shall not be deemed an admission that any of the foregoing persons is the beneficial owner of such shares for any other purpose. (2) The number of shares reported in the table above includes warrants to purchase up to 5,822,829 shares of the common stock of C4 Therapeutics, Inc. (the "Issuer"). (3) The percentage set forth in row 11 is calculated based upon 96,914,418 shares of the common stock of the Issuer outstanding as of October 29, 2025, as reported on the cover of the Issuer's Quarterly Report on Form 10-Q for the period ended September 30, 2025 filed with the Securities and Exchange Commission on November 6, 2025 (the "Form 10-Q"). Soleus Private Equity GP III, LLC DE 0.00 6072822.00 0.00 6072822.00 6072822.00 N 5.9 OO (1) The shares reported in the table above are held directly by Soleus PE. Soleus PE GP is the sole general partner of Soleus PE, Soleus PE GP III, LLC is the sole manager of Soleus PE GP, SCM is the investment manager for Soleus PE and for Master Fund, and Soleus GP, LLC is the sole general partner of SCM. Guy Levy is the sole managing member of each of Soleus PE GP III, LLC and of Soleus GP, LLC. Each of Mr. Levy, Soleus PE GP III, LLC, Soleus PE GP, SCM and Soleus GP, LLC disclaims beneficial ownership of these shares held by Soleus PE other than for the purpose of determining their obligations under Section 13(d) of the Exchange Act, and the filing of this report shall not be deemed an admission that any of the foregoing persons is the beneficial owner of such shares for any other purpose. (2) The number of shares reported in the table above includes warrants to purchase up to 5,822,829 shares of the common stock of the Issuer. (3) The percentage set forth in row 11 is calculated based upon 96,914,418 shares of the common stock of the Issuer outstanding as of October 29, 2025, as set forth on the cover of the Form 10-Q. Soleus PE GP III, LLC DE 0.00 6072822.00 0.00 6072822.00 6072822.00 N 5.9 OO (1) The shares reported in the table above are held directly by Soleus PE. Soleus PE GP is the sole general partner of Soleus PE, Soleus PE GP III, LLC is the sole manager of Soleus PE GP, SCM is the investment manager for Soleus PE and for Master Fund, and Soleus GP, LLC is the sole general partner of SCM. Guy Levy is the sole managing member of each of Soleus PE GP III, LLC and of Soleus GP, LLC. Each of Mr. Levy, Soleus PE GP III, LLC, Soleus PE GP, SCM and Soleus GP, LLC disclaims beneficial ownership of these shares held by Soleus PE other than for the purpose of determining their obligations under Section 13(d) of the Exchange Act, and the filing of this report shall not be deemed an admission that any of the foregoing persons is the beneficial owner of such shares for any other purpose. (2) The number of shares reported in the table above includes warrants to purchase up to 5,822,829 shares of the common stock of the Issuer. (3) The percentage set forth in row 11 is calculated based upon 96,914,418 shares of the common stock of the Issuer outstanding as of October 29, 2025, as set forth on the cover of the Form 10-Q. Soleus Capital Master Fund, L.P. E9 0.00 10361860.00 0.00 10361860.00 10361860.00 N 9.99 FI (1) The shares reported in the table above are held directly by Master Fund. Soleus Capital, LLC is the sole general partner of Master Fund, Soleus Capital Group, LLC ("SCG") is the sole managing member of Soleus Capital, LLC, SCM is the investment manager for Soleus PE and for Master Fund, and Soleus GP, LLC is the sole general partner of SCM. Guy Levy is the sole managing member of each of SCG and of Soleus GP, LLC. Each of SCG, Soleus Capital, LLC, SCM, Soleus GP, LLC and Mr. Levy disclaims beneficial ownership of these shares held by Master Fund other than for the purpose of determining their obligations under Section 13(d) of the Exchange Act, and the filing of this report shall not be deemed an admission that any of the foregoing persons is the beneficial owner of such shares for any other purpose. (2) The number of shares reported in the table above includes warrants to purchase up to 6,807,911 shares of the common stock of the Issuer, and reflects the maximum number of shares of common stock that may be held by the Reporting Person as a result of the beneficial ownership limitations set forth in such warrants. (3) The percentage set forth in row 11 is calculated based upon 96,914,418 shares of the common stock of the Issuer outstanding as of October 29, 2025, as set forth on the cover of the Form 10-Q. Soleus Capital, LLC DE 0.00 10361860.00 0.00 10361860.00 10361860.00 N 9.99 OO (1) The shares reported in the table above are held directly by Master Fund. Soleus Capital, LLC is the sole general partner of Master Fund, SCG is the sole managing member of Soleus Capital, LLC, SCM is the investment manager for Soleus PE and for Master Fund, and Soleus GP, LLC is the sole general partner of SCM. Guy Levy is the sole managing member of each of SCG and of Soleus GP, LLC. Each of SCG, Soleus Capital, LLC, SCM, Soleus GP, LLC and Mr. Levy disclaims beneficial ownership of these shares held by Master Fund other than for the purpose of determining their obligations under Section 13(d) of the Exchange Act, and the filing of this report shall not be deemed an admission that any of the foregoing persons is the beneficial owner of such shares for any other purpose. (2) The number of shares reported in the table above includes warrants to purchase up to 6,807,911 shares of the common stock of the Issuer, and reflects the maximum number of shares of common stock that may be held by the Reporting Person as a result of the beneficial ownership limitations set forth in such warrants. (3) The percentage set forth in row 11 is calculated based upon 96,914,418 shares of the common stock of the Issuer outstanding as of October 29, 2025, as set forth on the cover of the Form 10-Q. Soleus Capital Group, LLC DE 0.00 10361860.00 0.00 10361860.00 10361860.00 N 9.99 OO (1) The shares reported in the table above are held directly by Master Fund. Soleus Capital, LLC is the sole general partner of Master Fund, SCG is the sole managing member of Soleus Capital, LLC, SCM is the investment manager for Soleus PE and for Master Fund, and Soleus GP, LLC is the sole general partner of SCM. Guy Levy is the sole managing member of each of SCG and of Soleus GP, LLC. Each of SCG, Soleus Capital, LLC, SCM, Soleus GP, LLC and Mr. Levy disclaims beneficial ownership of these shares held by Master Fund other than for the purpose of determining their obligations under Section 13(d) of the Exchange Act, and the filing of this report shall not be deemed an admission that any of the foregoing persons is the beneficial owner of such shares for any other purpose. (2) The number of shares reported in the table above includes warrants to purchase up to 6,807,911 shares of the common stock of the Issuer, and reflects the maximum number of shares of common stock that may be held by the Reporting Person as a result of the beneficial ownership limitations set forth in such warrants. (3) The percentage set forth in row 11 is calculated based upon 96,914,418 shares of the common stock of the Issuer outstanding as of October 29, 2025, as set forth on the cover of the Form 10-Q. Soleus Capital Management, L.P. DE 0.00 10334114.00 0.00 10334114.00 10334114.00 N 9.99 PN (1) The shares reported in the table above are held directly by Soleus PE and by Master Fund. Soleus PE GP is the sole general partner of Soleus PE, Soleus PE GP III, LLC is the sole manager of Soleus PE GP, SCM is the investment manager for Soleus PE, and Soleus GP, LLC is the sole general partner of SCM. Soleus Capital, LLC is the sole general partner of Master Fund, SCG is the sole managing member of Soleus Capital, LLC, SCM is the investment manager for Master Fund, and Soleus GP, LLC is the sole general partner of SCM. Guy Levy is the sole managing member of each of Soleus PE GP III, LLC, SCG and Soleus GP, LLC. Each of Soleus PE GP, Soleus PE GP III, LLC, Soleus Capital, LLC, SCG, SCM, Soleus GP, LLC and Mr. Levy disclaims beneficial ownership of these shares held directly by Soleus PE and Master Fund other than for the purpose of determining their obligations under Section 13(d) of the Exchange Act, and the filing of this report shall not be deemed an admission that any of the foregoing persons is the beneficial owner of such shares for any other purpose. (2) The number of shares reported in the table above includes warrants to purchase up to 6,530,172 shares of the common stock of the Issuer, and reflects the maximum number of shares of common stock that may be held by the Reporting Person as a result of the beneficial ownership limitations set forth in such warrants. (3) The percentage set forth in row 11 is calculated based upon 96,914,418 shares of the common stock of the Issuer outstanding as of October 29, 2025, as set forth on the cover of the Form 10-Q. Soleus GP, LLC DE 0.00 10334114.00 0.00 10334114.00 10334114.00 N 9.99 OO (1) The shares reported in the table above are held directly by Soleus PE and by Master Fund. Soleus PE GP is the sole general partner of Soleus PE, Soleus PE GP III, LLC is the sole manager of Soleus PE GP, SSCM is the investment manager for Soleus PE, and Soleus GP, LLC is the sole general partner of SCM. Soleus Capital, LLC is the sole general partner of Master Fund, SCG is the sole managing member of Soleus Capital, LLC, SCM is the investment manager for Master Fund, and Soleus GP, LLC is the sole general partner of SCM. Guy Levy is the sole managing member of each of Soleus PE GP III, LLC, SCG and Soleus GP, LLC. Each of Soleus PE GP, Soleus PE GP III, LLC, Soleus Capital, LLC, SCG, SCM, Soleus GP, LLC and Mr. Levy disclaims beneficial ownership of these shares held directly by Soleus PE and Master Fund other than for the purpose of determining their obligations under Section 13(d) of the Exchange Act, and the filing of this report shall not be deemed an admission that any of the foregoing persons is the beneficial owner of such shares for any other purpose. (2) The number of shares reported in the table above includes warrants to purchase up to 6,530,172 shares of the common stock of the Issuer, and reflects the maximum number of shares of common stock that may be held by the Reporting Person as a result of the beneficial ownership limitations set forth in such warrants. (3) The percentage set forth in row 11 is calculated based upon 96,914,418 shares of the common stock of the Issuer outstanding as of October 29, 2025, as set forth on the cover of the Form 10-Q. Guy Levy X1 0.00 10334114.00 0.00 10334114.00 10334114.00 N 9.99 IN (1) The shares reported in the table above are held directly by Soleus PE and by Master Fund. Soleus PE GP is the sole general partner of Soleus PE, Soleus PE GP III, LLC is the sole manager of Soleus PE GP, SCM is the investment manager for Soleus PE, and Soleus GP, LLC is the sole general partner of SCM. Soleus Capital, LLC is the sole general partner of Master Fund, SCG is the sole managing member of Soleus Capital, LLC, SCM is the investment manager for Master Fund, and Soleus GP, LLC is the sole general partner of SCM. Guy Levy is the sole managing member of each of Soleus PE GP III, LLC, SCG and Soleus GP, LLC. Each of Soleus PE GP, Soleus PE GP III, LLC, Soleus Capital, LLC, SCG, SCM, Soleus GP, LLC and Mr. Levy disclaims beneficial ownership of these shares held directly by Soleus PE and Master Fund other than for the purpose of determining their obligations under Section 13(d) of the Exchange Act, and the filing of this report shall not be deemed an admission that any of the foregoing persons is the beneficial owner of such shares for any other purpose. (2) The number of shares reported in the table above includes warrants to purchase up to 6,530,172 shares of the common stock of the Issuer, and reflects the maximum number of shares of common stock that may be held by the Reporting Person as a result of the beneficial ownership limitations set forth in such warrants. (3) The percentage set forth in row 11 is calculated based upon 96,914,418 shares of the common stock of the Issuer outstanding as of October 29, 2025, as set forth on the cover of the Form 10-Q. C4 Therapeutics, Inc 490 Arsenal Way, Suite 120, Watertown, MA 02472 Soleus Private Equity GP III, LLC Soleus Private Equity Fund III, L.P. Soleus PE GP III, LLC Soleus Capital Master Fund, L.P. Soleus Capital, LLC Soleus Capital Group, LLC Soleus Capital Management, L.P. Soleus GP, LLC Guy Levy Soleus Private Equity GP III, LLC 100 Field Point Road, Suite 200 Greenwich, CT 06830 Soleus Private Equity Fund III, L.P. 100 Field Point Road, Suite 200 Greenwich, CT 06830 Soleus PE GP III, LLC 100 Field Point Road, Suite 200 Greenwich, CT 06830 Soleus Capital Master Fund, L.P. 100 Field Point Road, Suite 200 Greenwich, CT 06830 Soleus Capital, LLC 100 Field Point Road, Suite 200 Greenwich, CT 06830 Soleus Capital Group, LLC 100 Field Point Road, Suite 200 Greenwich, CT 06830 Soleus Capital Management, L.P. 100 Field Point Road, Suite 200 Greenwich, CT 06830 Soleus GP, LLC 100 Field Point Road, Suite 200 Greenwich, CT 06830 Guy Levy c/o Soleus Capital Management, L.P. 100 Field Point Road, Suite 200 Greenwich, CT 06830 Soleus Private Equity GP III, LLC - Delaware Soleus Private Equity Fund III, L.P. - Delaware Soleus PE GP III, LLC - Delaware Soleus Capital Master Fund, L.P. - Cayman Islands Soleus Capital, LLC - Delaware Soleus Capital Group, LLC - Delaware Soleus Capital Management, L.P. - Delaware Soleus GP, LLC - Delaware Guy Levy - United States Y The information in rows 5 through 9 and 11 on the cover pages to this Schedule 13G, including the footnotes thereto, is hereby incorporated by reference. Soleus Private Equity GP III, LLC - 6,072,822 Soleus Private Equity Fund III, L.P. - 6,072,822 Soleus PE GP III, LLC - 6,072,822 Soleus Capital Master Fund, L.P. - 10,361,860 Soleus Capital, LLC - 10,361,860 Soleus Capital Group, LLC - 10,361,860 Soleus Capital Management, L.P. - 10,334,114 Soleus GP, LLC - 10,334,114 Guy Levy - 10,334,114 Soleus Private Equity GP III, LLC - 5.9% Soleus Private Equity Fund III, L.P. - 5.9% Soleus PE GP III, LLC - 5.9% Soleus Capital Master Fund, L.P. - 9.99% Soleus Capital, LLC - 9.99% Soleus Capital Group, LLC - 9.99% Soleus Capital Management, L.P. - 9.99% Soleus GP, LLC - 9.99% Guy Levy - 9.99% 0 Soleus Private Equity GP III, LLC - 6,072,822 Soleus Private Equity Fund III, L.P. - 6,072,822 Soleus PE GP III, LLC - 6,072,822 Soleus Capital Master Fund, L.P. - 10,361,860 Soleus Capital, LLC - 10,361,860 Soleus Capital Group, LLC - 10,361,860 Soleus Capital Management, L.P. - 10,334,114 Soleus GP, LLC - 10,334,114 Guy Levy - 10,334,114 0 Soleus Private Equity GP III, LLC - 6,072,822 Soleus Private Equity Fund III, L.P. - 6,072,822 Soleus PE GP III, LLC - 6,072,822 Soleus Capital Master Fund, L.P. - 10,361,860 Soleus Capital, LLC - 10,361,860 Soleus Capital Group, LLC - 10,361,860 Soleus Capital Management, L.P. - 10,334,114 Soleus GP, LLC - 10,334,114 Guy Levy - 10,334,114 Y Y Y Y Y N By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11. Soleus Private Equity Fund III, L.P. /s/ Guy Levy 02/12/2026 Soleus Private Equity GP III, LLC /s/ Guy Levy 02/12/2026 Soleus PE GP III, LLC /s/ Guy Levy 02/12/2026 Soleus Capital Master Fund, L.P. /s/ Guy Levy 02/12/2026 Soleus Capital, LLC /s/ Guy Levy 02/12/2026 Soleus Capital Group, LLC /s/ Guy Levy 02/12/2026 Soleus Capital Management, L.P. /s/ Guy Levy 02/12/2026 Soleus GP, LLC /s/ Guy Levy 02/12/2026 Guy Levy /s/ Guy Levy 02/12/2026