Company: CSTL
Filing Date: 2025-11-03
Form Type: 10-Q
Source: 0001628280-25-048254
Chunk: 30

Company: CASTLE BIOSCIENCES INC
Filing Date: 2025-11-03
Form: 10-Q
Item: Item 1
Chunk 30
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840,192 $36.17 4.8$8,933 Restricted Stock UnitsThe following table summarizes our RSU activity for the nine months ended September 30, 2025:Restricted Stock Units OutstandingWeighted-Average Grant Date Fair ValueBalance as of December 31, 20243,196,224 $23.52 Granted1,542,992 $21.14 Vested(1)(601,937)$23.50 Forfeited/Cancelled(226,090)$23.44 Balance as of September 30, 20253,911,189$22.59 (1)The aggregate number of shares withheld upon vesting for employee tax obligations was 167,751 for the nine months ended September 30, 2025.

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Table of ContentsCASTLE BIOSCIENCES, INC.NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (Continued)(UNAUDITED)

Performance-Based Restricted Stock UnitsThe following table summarizes our PSU activity for the nine months ended September 30, 2025:Performance-Based Restricted Stock Units OutstandingWeighted-Average Grant Date Fair ValueBalance as of December 31, 2024275,528 $21.94 Granted172,631 $22.23 Vested(98,015)$23.23 Forfeited/Cancelled— $— Balance as of September 30, 2025350,144$21.72 (1)The aggregate number of shares withheld upon vesting for employee tax obligations was 35,426 for the nine months ended September 30, 2025.Employee Stock Purchase PlanThe ESPP provides for certain automatic increases in the number of shares of common stock reserved for issuance, which resulted in an additional 284,831 shares becoming available under the ESPP effective January 1, 2025. During the nine months ended September 30, 2025, we issued 160,898 shares of common stock pursuant to scheduled purchases under the ESPP. As of September 30, 2025, 1,170,613 shares remained available for issuance under the ESPP.Determining Fair Value - Summary of AssumptionsWe use the Black-Scholes option pricing model to estimate the fair value of each option grant on the date of grant or any other measurement date. The following table sets forth the assumptions used to determine the fair value of stock options: Nine Months EndedSeptember 30,