MAETZOLD DEREK J 4

What Happened
Derek J. Maetzold, President, Chief Executive Officer and a director of Castle Biosciences (CSTL), sold 4,017 shares on January 20, 2026. The weighted-average sale price was $40.01, for aggregate proceeds of approximately $160,732. The filing identifies the transaction as a sale (code S) and notes the trades were executed in multiple transactions at prices ranging from $39.695 to $40.25.

Key Details

• Transaction date: 2026-01-20; weighted-average price $40.01; price range $39.695–$40.25.
• Shares sold: 4,017; proceeds ≈ $160,732.
• Plan/authorization: Executed pursuant to a Rule 10b5-1 trading plan adopted by Maetzold on May 8, 2025 (Footnote F1).
• Trade execution detail: Multiple trades; reporting person offers to provide per-trade price/quantity on request (Footnote F2).
• Post-transaction holdings: Not specified in the provided filing excerpts.
• Filing timeliness: Report filed Jan 22, 2026 (appears timely based on the Jan 20 transaction).

Context
A 10b5-1 plan is a prearranged trading program that allows insiders to sell shares at scheduled times; such sales are often routine and do not necessarily indicate a change in management’s view of the company. Several footnotes in the filing reference family trusts and grantor retained annuity trusts that hold shares for Maetzold’s family members, but the filing does not specify which account(s) funded this particular sale.