Castle Biosciences (CSTL) CEO Derek Maetzold Exercises Options, Sells Shares

What Happened Derek J. Maetzold, President & Chief Executive Officer and a director of Castle Biosciences (CSTL), exercised stock options and sold shares on September 21, 2026. He exercised 8,580 option shares at a $2.39 strike (cash cost $20,506). Separately, he sold a total of 14,496 shares in open‑market transactions at a weighted average price of $35.33 for aggregate gross proceeds of approximately $512,202. The filing also reports an 8,580‑share derivative conversion/disposition reported at $0.

Key Details

• Transaction date: 2026-09-21; Form 4 filed 2026-09-23 (timely — within the 2 business‑day window).
• Option exercise: 8,580 shares at $2.39 per share (total exercise cost $20,506). Options are fully vested (footnote F13).
• Open‑market sales: 8,580; 3,198; and 2,718 shares (total 14,496) at a weighted average price of $35.33, range $35.02–$35.665 (footnote F2); total proceeds ≈ $512,202.
• A derivative disposition of 8,580 shares is reported at $0 (reported separately in the filing).
• Transactions were made pursuant to a Rule 10b5‑1 trading plan adopted June 2, 2026 (footnote F1).
• Several holdings are held in various trusts of which Mr. Maetzold is trustee or beneficiary (footnotes F3–F12).
• Shares owned after the transactions are not specified in the provided summary.

Context This was an option exercise (code M) combined with immediate/open‑market sales (code S). Because the sales were executed under a prearranged 10b5‑1 plan and the options were fully vested, the activity appears to be a planned disposition rather than an ad‑hoc trade; filings are factual records and do not itself indicate insider sentiment. If you want a follow‑up, you can request the full trade-by-trade breakdown (prices and share counts) the reporting person offered to provide per footnote F2.