X0202 SCHEDULE 13G/A 0002050709-26-000018 0002050709 XXXXXXXX LIVE 1 Common Stock, $0.0001 par value per share 06/30/2026 0001662579 C4 Therapeutics, Inc. 12529R107 490 ARSENAL WAY SUITE 120 WATERTOWN MA 02472 Rule 13d-1(b) Squadron Master Fund LP DE 0.00 7600000.00 0.00 7600000.00 7600000.00 6.9 PN Squadron Capital Management LLC DE 0.00 7600000.00 0.00 7600000.00 7600000.00 6.9 IA HC Matthew Sesterhenn X1 0.00 7600000.00 0.00 7600000.00 7600000.00 6.9 HC IN William Blank X1 0.00 7600000.00 0.00 7600000.00 7600000.00 6.9 HC IN C4 Therapeutics, Inc. 490 ARSENAL WAY, SUITE 120, WATERTOWN, MASSACHUSETTS, 02472. Squadron Master Fund LP Squadron Capital Management, LLC Matthew Sesterhenn William Blank Squadron Master Fund LP c/o Squadron Capital Management, LLC 1211 West 22nd Street, Suite 1008 Oak Brook, IL 60523 Squadron Capital Management, LLC 1211 West 22nd Street, Suite 1008 Oak Brook, IL 60523 Matthew Sesterhenn c/o Squadron Capital Management, LLC 1211 West 22nd Street, Suite 1008 Oak Brook, IL 60523 William Blank c/o Squadron Capital Management, LLC 1211 West 22nd Street, Suite 1008 Oak Brook, IL 60523 Squadron Master Fund LP - Delaware Squadron Capital Management, LLC - Delaware Matthew Sesterhenn - United States William Blank - United States N IA HC Squadron Capital Management, LLC is an investment adviser that is registered under the Investment Advisers Act of 1940. Squadron Capital Management, LLC, which serves as investment adviser to private funds, including but not limited to Squadron Master Fund LP (collectively, the "Funds"), may be deemed to be the beneficial owner of all shares of Common Stock held by the Funds. Mr. Sesterhenn and Mr. Blank, as Partners of Squadron Capital Management, LLC, with the power to exercise investment and voting discretion, may be deemed to be the beneficial owner of all shares of Common Stock held by the Funds. Pursuant to Rule 13d-4 under the Securities Exchange Act of 1934, as amended, Squadron Capital Management, LLC and Mr. Sesterhenn and Mr. Blank expressly disclaim beneficial ownership over any of the securities reported in this statement, and the filing of this statement shall not be construed as an admission that Squadron Capital Management, LLC or Mr. Sesterhenn and Mr. Blank are the beneficial owner of any of the securities reported herein. This amount comprises beneficial ownership of 7,600,000 shares of Common Stock which consists of (i) 7,200,000 shares of Common Stock and (ii) 400,000 shares of Common Stock underlying long call options held by Squadron Capital Management LLC that are currently exercisable (the "Options"). Squadron Master Fund LP - 7,600,000 shares Squadron Capital Management, LLC - 7,600,000 shares Matthew Sesterhenn - 7,600,000 shares William Blank - 7,600,000 shares All such shares of Common Stock in the aggregate represent beneficial ownership of approximately 6.9% of the Common Stock based on (i) 110,567,222 shares of Common Stock outstanding, $0.0001 par value per share, as of May 1, 2026, as reported by the Issuer on Form 10-Q filed with the Securities and Exchange Commission on May 12, 2026, plus (ii) 400,000 shares of Common Stock issuable upon exercise of the Options. Squadron Master Fund LP - 6.9% Squadron Capital Management, LLC - 6.9% Matthew Sesterhenn - 6.9% William Blank - 6.9% Squadron Master Fund LP - 0 Squadron Capital Management, LLC - 0 Matthew Sesterhenn - 0 William Blank - 0 Squadron Master Fund LP - 7,600,000 shares Squadron Capital Management, LLC - 7,600,000 shares Matthew Sesterhenn - 7,600,000 shares William Blank - 7,600,000 shares Squadron Master Fund LP - 0 Squadron Capital Management, LLC - 0 Matthew Sesterhenn - 0 William Blank - 0 Squadron Master Fund LP - 7,600,000 shares Squadron Capital Management, LLC - 7,600,000 shares Matthew Sesterhenn - 7,600,000 shares William Blank - 7,600,000 shares Y N The Funds have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, the shares of Common Stock covered by this Statement. N See Notes above. Y Y N By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and 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. Squadron Master Fund LP /s/ Matthew Sesterhenn 08/14/2026 Squadron Capital Management LLC /s/ Matthew Sesterhenn 08/14/2026 Matthew Sesterhenn /s/ Matthew Sesterhenn 08/14/2026 William Blank /s/ William Blank 08/14/2026