CCCC · C4 Therapeutics, Inc.

Represents shares withheld by the Issuer to satisfy tax withholding obligations in connection with the vesting and settlement of RSUs and does not represent a sale by the Reporting Person.

Reflects the acquisition of shares of Common Stock upon vesting of previously disclosed grants of restricted stock units ("RSUs"). The grant of RSUs was initially reported in Table I of the Form 4 filed by the Reporting Person on July 12, 2023.

These shares were issued in accordance with the Issuer's Non-Employee Director Compensation Policy, pursuant to which the Reporting Person elected to receive shares of the Issuer's common stock in lieu of cash compensation for services as a non-employee director of the Issuer.

The price reported in Column 4 is based upon the closing market price of the Issuer's common stock on July 1, 2026.

These shares were issued in accordance with the Issuer's Non-Employee Director Compensation Policy, pursuant to which the Reporting Person elected to receive shares of the Issuer's common stock in lieu of cash compensation for services as a non-employee director of the Issuer.

The price reported in Column 4 is based upon the closing market price of the Issuer's common stock on July 1, 2026.

This option shall vest and become exercisable in full upon the earlier to occur of (i) June 24, 2027 and (ii) the next annual meeting of the Issuer's stockholders, subject to the recipient's continued service as a member of the Board on such date.

This option shall vest and become exercisable in full upon the earlier to occur of (i) June 24, 2027 and (ii) the next annual meeting of the Issuer's stockholders, subject to the recipient's continued service as a member of the Board on such date.

This option shall vest and become exercisable in full upon the earlier to occur of (i) June 24, 2027 and (ii) the next annual meeting of the Issuer's stockholders, subject to the recipient's continued service as a member of the Board on such date.

This option shall vest and become exercisable in full upon the earlier to occur of (i) June 24, 2027 and (ii) the next annual meeting of the Issuer's stockholders, subject to the recipient's continued service as a member of the Board on such date.

This option shall vest and become exercisable in full upon the earlier to occur of (i) June 24, 2027 and (ii) the next annual meeting of the Issuer's stockholders, subject to the recipient's continued service as a member of the Board on such date.

This option shall vest and become exercisable in full upon the earlier to occur of (i) June 24, 2027 and (ii) the next annual meeting of the Issuer's stockholders, subject to the recipient's continued service as a member of the Board on such date.

This option shall vest and become exercisable in full upon the earlier to occur of (i) June 24, 2027 and (ii) the next annual meeting of the Issuer's stockholders, subject to the recipient's continued service as a member of the Board on such date.

This option shall vest and become exercisable in full upon the earlier to occur of (i) June 24, 2027 and (ii) the next annual meeting of the Issuer's stockholders, subject to the recipient's continued service as a member of the Board on such date.

The reported transaction represents the exercise of a stock option for cash. No shares were sold in connection with the exercise.

The shares underlying this option are fully vested and exercisable.

The reported transaction represents the exercise of a stock option for cash. No shares were sold in connection with the exercise.

These shares were issued in accordance with the Issuer's Non-Employee Director Compensation Policy, pursuant to which the Reporting Person elected to receive shares of the Issuer's common stock in lieu of cash compensation for services as a non-employee director of the Issuer.

The price reported in Column 4 is based upon the closing market price of the Issuer's common stock on April 1, 2026.

These shares were issued in accordance with the Issuer's Non-Employee Director Compensation Policy, pursuant to which the Reporting Person elected to receive shares of the Issuer's common stock in lieu of cash compensation for services as a non-employee director of the Issuer.

The price reported in Column 4 is based upon the closing market price of the Issuer's common stock on April 1, 2026.

Represents shares withheld by the Issuer to satisfy tax withholding obligations in connection with the vesting and settlement of RSUs and does not represent a sale by the Reporting Person.

Reflects the acquisition of shares of Common Stock upon vesting of previously disclosed grants of RSUs. The grants of RSUs were initially reported in Table I of the Forms 4 filed by the Reporting Person on February 15, 2023, February 15, 2024 and February 18, 2025.

Represents shares withheld by the Issuer to satisfy tax withholding obligations in connection with the vesting and settlement of RSUs and does not represent a sale by the Reporting Person.

Reflects the acquisition of shares of Common Stock upon vesting of previously disclosed grants of RSUs. The grants of RSUs were initially reported in Table I of the Forms 4 filed by the Reporting Person on February 15, 2023, February 14, 2024 and February 18, 2025.

Represents shares withheld by the Issuer to satisfy tax withholding obligations in connection with the vesting and settlement of RSUs and does not represent a sale by the Reporting Person.

Represents shares withheld by the Issuer to satisfy tax withholding obligations in connection with the vesting and settlement of RSUs and does not represent a sale by the Reporting Person.

Reflects the acquisition of shares of Common Stock upon vesting of previously disclosed grants of RSUs. The grants of RSUs were initially reported in Table I of the Forms 4 filed by the Reporting Person on February 15, 2023, February 14, 2024 and February 18, 2025.

Reflects the acquisition of shares of Common Stock upon vesting of previously disclosed grants of RSUs. The grants of RSUs were initially reported in Table I of the Forms 4 filed by the Reporting Person on April 10, 2024 and February 18, 2025.

Reflects the acquisition of shares of Common Stock upon vesting of a previously disclosed grant of RSUs. The grant of RSUs was initially reported in Table I of the Forms 4 filed by the Reporting Person on February 18, 2025.

Reflects the acquisition of shares of Common Stock upon vesting of previously disclosed grants of RSUs. The grants of RSUs were initially reported in Table I of the Forms 4 filed by the Reporting Person on February 15, 2023, February 14, 2024 and February 18, 2025.

Reflects the acquisition of shares of Common Stock upon vesting of previously disclosed grants of RSUs. The grants of RSUs were initially reported in Table I of the Forms 4 filed by the Reporting Person on February 15, 2023, February 14, 2024 and February 18, 2025.

Represents shares withheld by the Issuer to satisfy tax withholding obligations in connection with the vesting and settlement of RSUs and does not represent a sale by the Reporting Person.

Represents shares withheld by the Issuer to satisfy tax withholding obligations in connection with the vesting and settlement of RSUs and does not represent a sale by the Reporting Person.

Reflects the acquisition of shares of Common Stock upon vesting of previously disclosed grants of RSUs. The grants of RSUs were initially reported in Table I of the Forms 4 filed by the Reporting Person on February 15, 2023, February 15, 2024 and February 18, 2025.

Reflects the acquisition of shares of Common Stock upon vesting of previously disclosed grants of RSUs. The grants of RSUs were initially reported in Table I of the Forms 4 filed by the Reporting Person on February 14, 2024 and February 18, 2025.

Represents shares withheld by the Issuer to satisfy tax withholding obligations in connection with the vesting and settlement of RSUs and does not represent a sale by the Reporting Person.

Reflects the acquisition of shares of Common Stock upon vesting of previously disclosed grants of RSUs. The grants of RSUs were initially reported in Table I of the Forms 4 filed by the Reporting Person on February 15, 2023, February 14, 2024 and February 18, 2025.

Represents restricted stock units ("RSUs"). Each RSU represents the contingent right to receive one share of the Issuer's Common Stock upon vesting and settlement. The RSUs shall vest as follows: (i) 100,000 RSUs shall vest in three equal annual installments following the grant date, with the first installment vesting on February 13, 2027, and (ii) 100,000 RSUs shall vest in full on February 13, 2029, subject to potential acceleration upon achievement of certain performance milestones.

Represents restricted stock units ("RSUs"). Each RSU represents the contingent right to receive one share of the Issuer's Common Stock upon vesting and settlement. The RSUs shall vest as follows: (i) 28,490 RSUs shall vest in three equal annual installments following the grant date, with the first installment vesting on February 13, 2027, and (ii) 28,490 RSUs shall vest in full on February 13, 2029, subject to potential acceleration upon achievement of certain performance milestones.

Represents restricted stock units ("RSUs"). Each RSU represents the contingent right to receive one share of the Issuer's Common Stock upon vesting and settlement. The RSUs shall vest as follows: (i) 120,000 RSUs shall vest in three equal annual installments following the grant date, with the first installment vesting on February 13, 2027, and (ii) 120,000 RSUs shall vest in full on February 13, 2029, subject to potential acceleration upon achievement of certain performance milestones.

Represents shares withheld by the Issuer to satisfy tax withholding obligations in connection with the vesting and settlement of RSUs and does not represent a sale by the Reporting Person.

Represents shares withheld by the Issuer to satisfy tax withholding obligations in connection with the vesting and settlement of RSUs and does not represent a sale by the Reporting Person.

Reflects the acquisition of shares of Common Stock upon vesting of previously disclosed grants of RSUs. The grants of RSUs were initially reported in Table I of the Forms 4 filed by the Reporting Person on February 15, 2023, February 14, 2024 and February 18, 2025.

Represents restricted stock units ("RSUs"). Each RSU represents the contingent right to receive one share of the Issuer's Common Stock upon vesting and settlement. The RSUs shall vest as follows: (i) 350,000 RSUs shall vest in three equal annual installments following the grant date, with the first installment vesting on February 13, 2027, and (ii) 350,000 RSUs shall vest in full on February 13, 2029, subject to potential acceleration upon achievement of certain performance milestones.

Represents restricted stock units ("RSUs"). Each RSU represents the contingent right to receive one share of the Issuer's Common Stock upon vesting and settlement. The RSUs shall vest as follows: (i) 100,000 RSUs shall vest in three equal annual installments following the grant date, with the first installment vesting on February 13, 2027, and (ii) 100,000 RSUs shall vest in full on February 13, 2029, subject to potential acceleration upon achievement of certain performance milestones.

Represents restricted stock units ("RSUs"). Each RSU represents the contingent right to receive one share of the Issuer's Common Stock upon vesting and settlement. The RSUs shall vest as follows: (i) 120,000 RSUs shall vest in three equal annual installments following the grant date, with the first installment vesting on February 13, 2027, and (ii) 120,000 RSUs shall vest in full on February 13, 2029, subject to potential acceleration upon achievement of certain performance milestones.

Represents restricted stock units ("RSUs"). Each RSU represents the contingent right to receive one share of the Issuer's Common Stock upon vesting and settlement. The RSUs shall vest as follows: (i) 120,000 RSUs shall vest in three equal annual installments following the grant date, with the first installment vesting on February 13, 2027, and (ii) 120,000 RSUs shall vest in full on February 13, 2029, subject to potential acceleration upon achievement of certain performance milestones.

Reflects the acquisition of shares of Common Stock upon vesting of previously disclosed grants of RSUs. The grants of RSUs were initially reported in Table I of the Forms 4 filed by the Reporting Person on February 15, 2023, February 14, 2024 and February 18, 2025.

Represents shares withheld by the Issuer to satisfy tax withholding obligations in connection with the vesting and settlement of RSUs and does not represent a sale by the Reporting Person.

These shares were issued in accordance with the Issuer's Non-Employee Director Compensation Policy, pursuant to which the Reporting Person elected to receive shares of the Issuer's common stock in lieu of cash compensation for services as a non-employee director of the Issuer.

The price reported in Column 4 is based upon the closing market price of the Issuer's common stock on January 2, 2026.

These shares were issued in accordance with the Issuer's Non-Employee Director Compensation Policy, pursuant to which the Reporting Person elected to receive shares of the Issuer's common stock in lieu of cash compensation for services as a non-employee director of the Issuer.

The price reported in Column 4 is based upon the closing market price of the Issuer's common stock on January 2, 2026.

Reflects the acquisition of shares of Common Stock upon vesting of a previously disclosed grant of restricted stock units ("RSUs"). The grant of RSUs was initially reported in Table I of the Form 4 filed by the Reporting Person on October 28, 2024.

Represents shares withheld by the Issuer to satisfy tax withholding obligations in connection with the vesting and settlement of RSUs and does not represent a sale by the Reporting Person.