X0508 4 2026-01-12 0001447362 CASTLE BIOSCIENCES INC CSTL 0001782815 Stokes Frank C/O CASTLE BIOSCIENCES, INC. 505 S. FRIENDSWOOD DRIVE, SUITE 401 FRIENDSWOOD TX 77546 false true false false Chief Financial Officer 0 Common Stock 2026-01-12 4 A 0 8124 0 A 58450 D Performance-Based Stock Unit 2026-01-12 4 A 0 8124 0 A Common Stock 8124 8124 D 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. 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. /s/ Frank Stokes, Attorney-in-Fact 2026-01-14