144 0001992219 XXXXXXXX LIVE 0001662579 C4 Therapeutics, Inc. 001-39567 490 Arsenal Way Suite 120 Watertown MA 2472 617-231-0700 Mark Mossler Former Section 16 Officer Stock Options E*Trade

3 Edison Drive Alpharetta GA 30005

9087 35484.74 110567222 05/27/2026 Nasdaq Stock Options 02/14/2025 Grant under Issuer's 2020 Equity Incentive Plan C4 Therapeutics, Inc. N 29080 02/14/2025 These securities were acquired pursuant to an option grant under the Issuer's 2020 Equity Incentive Plan. 29,080 options were granted on February 14, 2025, of which 9,087 vested and were exercised and sold pursuant to a same-day sale transaction. Y 05/28/2026 Mark Mossler