Changes in Beneficial Ownership · 4

C4 Therapeutics, Inc.

CCCCNASDAQEQUITYCurrent

Changes in Beneficial Ownership

Filed Jul 13, 2026Accepted Jul 13, 2026, 4:33 PM EDTFiling CIK 1662579Accession 0001470831-26-000705

wk-form4_1783974826.xml

Name: REYNO LEONARD
Reporting owner CIK: 0001528716
Relationship: Officer
Officer title: Chief Medical Officer
Address: C/O C4 THERAPEUTICS, INC., 490 ARSENAL WAY #120, WATERTOWN, MA, 02472

Non-derivative transactions · 2 reported rows
Security	Transaction date	Code	Amount	A / D	Price (USD)	Owned after	Ownership	Timeliness
Common Stock	2026-07-10	M · Form 5^[F1]	15,325	A	0	379,803	D	E
Common Stock	2026-07-10	F · Form 4^[F2]	7,397	D	4.06	372,406	D

Table key

M · Form 5: Exempt derivative exercise or conversion under Rule 16b-3
A: Acquired
D: Direct
F · Form 4: Securities delivered or withheld for exercise price or tax liability under Rule 16b-3

F1: 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.↩ 1
F2: 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.↩ 1