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

Castle Biosciences' President and CEO, Derek J. Maetzold, sold 2,678 shares of common stock for approximately $39.23 per share under a pre-arranged 10b5-1 plan.

Summary

• Derek J. Maetzold, President & Chief Executive Officer and Director of Castle Biosciences Inc. (CSTL), reported a sale of common stock.
• The transaction involved the disposition of 2,678 shares of common stock.
• The shares were sold at a weighted-average price of $39.23 per share.
• The total value of the transaction was approximately $105,000 ($39.23 * 2,678 shares).
• The sale was executed on December 2, 2025.
• This transaction was conducted pursuant to a Rule 10b5-1 plan adopted by Mr. Maetzold on May 8, 2025.
• Following the transaction, Mr. Maetzold directly owns 38,886 shares.
• Mr. Maetzold indirectly owns 261,372 shares through various trusts, including The Maetzold Descendants 2020 Trust, Derek Maetzold 2020 Irrevocable Trust, several Maetzold 2018 Remainder Trusts, and DJM Grantor Retained Annuity Trusts No. 5, 6, and 7.

Sentiment

Score: 5

Explanation: The sale of shares by the CEO, while a reduction in direct ownership, was conducted under a pre-arranged Rule 10b5-1 plan, which typically indicates a planned liquidity event rather than a reaction to new company-specific negative news. This makes the sentiment neutral, as it's a routine disclosure of a planned transaction.

Negatives

• The reporting person, Derek J. Maetzold, reduced his direct beneficial ownership by 2,678 shares of common stock.

Future Outlook

NA

Industry Context

NA

Stakeholder Impact

• Shareholders may perceive a slight reduction in direct insider ownership, although the sale was pre-planned under a Rule 10b5-1 plan, which mitigates concerns about opportunistic selling.

Key Dates

Recommendation

The filing reports a pre-scheduled sale of a relatively small number of shares by the CEO under a Rule 10b5-1 plan. This type of transaction is generally considered a planned liquidity event rather than a signal of new fundamental information about the company. Therefore, it does not provide a basis for a change in investment recommendation, suggesting a 'hold' position is appropriate based solely on this filing.

Keywords

Castle Biosciences, CSTL, Insider Trading, Form 4, Stock Sale, Derek Maetzold, 10b5-1 Plan, Officer Transaction, Director Transaction