MAETZOLD DEREK J 4

What Happened
Derek J. Maetzold, President & Chief Executive Officer and a director of Castle Biosciences (CSTL), sold a total of 30,779 shares in open-market transactions between March 13 and March 16, 2026, generating approximately $792,410 in proceeds. The sales were carried out pursuant to a Rule 10b5-1 trading plan adopted December 3, 2025, and the reported prices (weighted averages where applicable) were $25.45, $25.96 and $26.68.

Key Details

• Transaction dates and amounts:
  • 2026-03-13: 13,204 shares sold at a weighted-average price of $25.45 for $336,002. (Footnote F2: multiple trades at $25.210–$25.785)
  • 2026-03-16: 17,449 shares sold at a weighted-average price of $25.96 for $453,046. (Footnote F3: multiple trades at $25.660–$26.630)
  • 2026-03-16: 126 shares sold at $26.68 for $3,362.
• Total shares sold: 30,779; total proceeds: ~$792,410.
• Shares owned after the transactions: not specified in the information provided in this summary.
• Notable footnotes: sales were made under a 10b5-1 plan (F1); some holdings referenced in the filing are held in various family or grantor retained annuity trusts (F4–F12).
• Filing/timeliness: Form 4 filed March 17, 2026 (covers trades on 3/13 and 3/16); filing appears to be within the standard two-business-day reporting window.

Context
These are open-market sales (code S) executed under a pre-established 10b5-1 plan. Such sales are generally considered routine liquidity transactions under a trading plan and do not by themselves indicate management’s view of the company’s near-term prospects. The filing includes weighted-average prices and notes that detailed trade-level data is available upon request to the SEC or issuer.