Paige Mahaney - 13 Feb 2026 Form 4 Insider Report for C4 Therapeutics, Inc. (CCCC)

Role: Chief Scientific Officer
Signature: /s/ Shagha Russell, Attorney-in-Fact
Issuer symbol: CCCC
Transactions as of: 13 Feb 2026
Net transactions value: -$4,623
Form type: 4
Filing time: 18 Feb 2026, 17:05:11 UTC
Previous filing: 30 Oct 2025
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Mahaney Paige	Chief Scientific Officer	C4 THERAPEUTICS, INC., 490 ARSENAL WAY, SUITE 120, WATERTOWN	/s/ Shagha Russell, Attorney-in-Fact	18 Feb 2026	0002040313

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	CCCC	Common Stock	Award	$0	+240,000	+242%	$0.000000	339,356	13 Feb 2026	Direct	F1
transaction	CCCC	Common Stock	Options Exercise	$0	+7,050	+2.1%	$0.000000	339,356	14 Feb 2026	Direct	F2
transaction	CCCC	Common Stock	Tax liability	$4,623	-2,446	-0.72%	$1.89	336,910	14 Feb 2026	Direct	F3

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	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.
F2	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.
F3	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.