X0306 4 2022-02-14 0 0001662579 C4 Therapeutics, Inc. CCCC 0001768223 Siegel Jolie C/O C4 THERAPEUTICS, INC. 490 ARSENAL WAY #200 WATERTOWN MA 02472 0 1 0 0 Chief Legal Officer Stock Option (Right to Buy) 22.71 2022-02-14 4 A 0 90000 0.00 A 2032-02-13 Common Stock 90000 90000 D Performance Restricted Stock Units 2022-02-14 4 A 0 26250 0.00 A 2025-02-28 Common Stock 26250 26250 D The shares underlying this option shall vest and become exercisable in sixteen equal quarterly installments following the grant date, with the first installment vesting on May 14, 2022. Each performance restricted stock unit ("PRSU") represents the contingent right to receive one share of the Issuer's Common Stock upon vesting and settlement. 4,500 PRSUs shall vest upon satisfaction of three escalating share price vesting milestones, and the remaining 21,750 PRSUs shall vest upon satisfaction of certain discovery and clinical milestones. /s/ Jolie Siegel 2022-02-16