Frank Stokes - 12 Jan 2026 Form 4 Insider Report for CASTLE BIOSCIENCES INC (CSTL)

Role: Chief Financial Officer
Signature: /s/ Frank Stokes, Attorney-in-Fact
Issuer symbol: CSTL
Transactions as of: 12 Jan 2026
Net transactions value: $0
Form type: 4
Filing time: 14 Jan 2026, 16:30:05 UTC
Previous filing: 15 Dec 2025
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Stokes Frank	Chief Financial Officer	C/O CASTLE BIOSCIENCES, INC., 505 S. FRIENDSWOOD DRIVE, SUITE 401, FRIENDSWOOD	/s/ Frank Stokes, Attorney-in-Fact	14 Jan 2026	0001782815

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	CSTL	Common Stock	Award	$0	+8,124	+16%	$0.000000	58,450	12 Jan 2026	Direct	F1

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
transaction	CSTL	Performance-Based Stock Unit	Award	$0	+8,124		$0.000000	8,124	12 Jan 2026	Common Stock	8,124		Direct	F2

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

Explanation of Responses:

Id	Content
F1	Represents 50% of the Performance-Based Stock Units ("PSUs") granted on March 4, 2024 ("2024 PSUs") that vested based on the satisfaction of certain performance criteria as certified by the board of directors of the Issuer on January 12, 2026.
F2	Each PSU represents the right to receive one share of the Issuer's Common Stock. These PSUs represent the remaining 50% of the 2024 PSUs which will vest subject to the achievement of certain milestones.