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

Role
Chief Accounting Officer
Signature
/s/ Shagha Russell, Attorney-in-Fact
Issuer symbol
CCCC
Transactions as of
13 Feb 2026
Net transactions value
-$6,177
Form type
4
Filing time
18 Feb 2026, 17:04:38 UTC
Previous filing
18 Feb 2025
SEC
View on sec.gov

Reporting Owners (1)

Name Relationship Address Signature Signature date CIK
Mossler Mark Chief Accounting Officer C/O C4 THERAPEUTICS, INC., 490 ARSENAL WAY #120, WATERTOWN /s/ Shagha Russell, Attorney-in-Fact 18 Feb 2026 0001992219

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
transaction CCCC Common Stock Award $0 +56,980 +313% $0.000000 75,184 13 Feb 2026 Direct F1
transaction CCCC Common Stock Options Exercise $0 +9,420 +14% $0.000000 75,184 14 Feb 2026 Direct F2
transaction CCCC Common Stock Tax liability $6,177 -3,268 -4.3% $1.89 71,916 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) 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.
F2 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.
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.