Castle Biosciences (CSTL) Insider Sale: 1,339 Shares via 10b5-1 Plan
Rhea-AI Filing Summary
Castle Biosciences (CSTL) director and CEO Derek J. Maetzold reported a sale of 1,339 shares of common stock on 10/02/2025 at a weighted-average price of $22.58 per share under a pre-existing Rule 10b5-1 trading plan adopted on 5/08/2025. After the transaction, the filing shows 64,327 shares held directly by the reporting person and multiple indirect holdings across family and trust vehicles, including trusts named in the filing.
The sale was executed in multiple trades at prices ranging from $22.31 to $23.14, and the filer said they will provide detailed trade-by-trade information upon request. The Form 4 is a routine Section 16 disclosure showing an insider sale conducted under an affirmative-defense plan rather than an ad-hoc transaction.
Positive
- None.
Negative
- None.
Insights
TL;DR: Sale executed under a Rule 10b5-1 plan, reducing concerns about opportunistic timing.
The director and CEO adopted a written 10b5-1 plan on 5/08/2025, and the reported sale of 1,339 shares on 10/02/2025 was implemented under that plan. Using a pre-established plan is a common governance practice to provide an affirmative defense against insider trading claims.
Risks remain if trades cluster near material events, but the filing states the sale was executed in multiple trades at prices between $22.31 and $23.14. Monitor any future Form 4 filings for additional planned or ad-hoc trades within the next several months.
TL;DR: The transaction size is small and routine relative to ongoing insider disclosures.
The Form 4 reports a disposal of 1,339 shares at a weighted-average price of $22.58, executed in multiple trades. The filing does not show any option exercises or derivative transactions tied to this sale.
Because the filing lists substantial indirect ownership across trusts and annuity vehicles, this sale alone is unlikely to materially change insider ownership concentration. Watch for further filings or material company announcements over the next 90 days for context.
Insider Trade Summary
| Type | Security | Shares | Price | Value |
|---|---|---|---|---|
| Sale | Common Stock | 1,339 | $22.58 | $30K |
| holding | Common Stock | -- | -- | -- |
| holding | Common Stock | -- | -- | -- |
| holding | Common Stock | -- | -- | -- |
| holding | Common Stock | -- | -- | -- |
| holding | Common Stock | -- | -- | -- |
| holding | Common Stock | -- | -- | -- |
| holding | Common Stock | -- | -- | -- |
| holding | Common Stock | -- | -- | -- |
| holding | Common Stock | -- | -- | -- |
Footnotes (1)
- These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on May 8, 2025. This transaction was executed in multiple trades at prices ranging from $22.31 to $23.14, inclusive. The price reported above reflects the weighted-average sale price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected. Held by The Maetzold Descendants 2020 Trust of which the Reporting Person's spouse is the trustee and the Reporting Person's spouse and their children are beneficiaries. Held by Derek Maetzold 2020 Irrevocable Trust of which the Reporting Person is the trustee and his children are beneficiaries. Held by The Maetzold 2018 Remainder Trust FBO Emily Carol Kirk of which the Reporting Person is the trustee and his child is the beneficiary. Held by The Maetzold 2018 Remainder Trust FBO Hannah Elizabeth Maetzold of which the Reporting Person is the trustee and his child is the beneficiary. Held by The Maetzold 2018 Remainder Trust FBO John Derek Maetzold of which the Reporting Person is the trustee and his child is the beneficiary. Held by The Maetzold 2018 Remainder Trust FBO Peter Douglas Maetzold of which the Reporting Person is the trustee and his child is the beneficiary. Held by DJM Grantor Retained Annuity Trust No. 5 of which the Reporting Person is the trustee and beneficiary. Held by DJM Grantor Retained Annuity Trust No. 6 of which the Reporting Person is the trustee and the beneficiaries are The Maetzold 2018 Remainder Trust FBO John Derek Maetzold, The Maetzold 2018 Remainder Trust FBO Emily Carol Kirk, The Maetzold 2018 Remainder Trust FBO Peter Douglas Maetzold and The Maetzold 2018 Remainder Trust FBO Hannah Elizabeth Maetzold. Held by DJM Grantor Retained Annuity Trust No. 7 of which the Reporting Person is the trustee and beneficiary.
