Form 4: Castle Biosciences CEO Sells Shares Under 10b5-1 Plan

Castle Biosciences President and CEO Derek J. Maetzold sold 4,017 shares of common stock for a weighted-average price of $40.013 per share as part of a pre-arranged Rule 10b5-1 trading plan.

Summary

• Derek J. Maetzold, President & Chief Exec. Officer and Director of Castle Biosciences Inc. (CSTL), reported a sale of common stock.
• The transaction involved the disposition of 4,017 shares of common stock.
• The shares were sold at a weighted-average price of $40.013 per share.
• The total value of the transaction was approximately $160,744.55 (4,017 shares * $40.013/share).
• This sale was executed on January 20, 2026.
• The transaction was made pursuant to a Rule 10b5-1 plan adopted by Mr. Maetzold on May 8, 2025.
• Following the transaction, Mr. Maetzold directly beneficially owns 87,715 shares of common stock.
• He also indirectly beneficially owns 216,469 shares through various trusts for family members and grantor retained annuity trusts.

Sentiment

Score: 5

Explanation: The transaction is a routine, pre-planned sale by an insider under a Rule 10b5-1 plan, which typically does not indicate a change in sentiment regarding the company's prospects.

Positives

• The sale was conducted under a pre-arranged Rule 10b5-1 plan, indicating a planned and systematic approach to stock disposition rather than an immediate reaction to market conditions.

Future Outlook

NA

Industry Context

NA

Related Party Transactions

• The reporting person holds significant indirect beneficial ownership through various trusts, including those for descendants and irrevocable trusts where his spouse or children are beneficiaries, and grantor retained annuity trusts where he is trustee and/or beneficiary. These structures represent related party holdings.

Stakeholder Impact

• Shareholders: A routine insider sale under a 10b5-1 plan is generally not seen as a significant signal for current shareholders, as it's a pre-planned liquidity event.
• Employees: No direct impact indicated.
• Customers: No direct impact indicated.
• Suppliers: No direct impact indicated.
• Creditors: No direct impact indicated.

Key Dates

Keywords

Castle Biosciences, CSTL, Derek J. Maetzold, insider trading, Form 4, stock sale, 10b5-1 plan, common stock, beneficial ownership, CEO, director