Company: CSTL
Filing Date: 2025-11-03
Form Type: 10-Q
Source: 0001628280-25-048254
Chunk: 129

Company: CASTLE BIOSCIENCES INC
Filing Date: 2025-11-03
Form: 10-Q
Item: Item 8
Chunk 129
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LE 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 30,20252024Average expected term (years)N/A5.0Expected stock price volatilityN/A80.20% - 80.20%Risk-free interest rateN/A4.39% - 4.39%Dividend yieldN/A—%The following table sets forth assumptions used to determine the fair value of the purchase rights issued under the ESPP: Nine Months EndedSeptember 30,20252024Average expected term (years)1.21.2Expected stock price volatility 56.55% - 85.21%59.85% - 130.95%Risk-free interest rate 3.52% - 4.22%3.82% - 5.33%Dividend yield—%—%We use the closing price of our common stock on the date of grant to determine the