Castle Biosciences (CSTL) CEO sells shares and exercises options under 10b5-1 plan
Filing Impact
Filing Sentiment
Form Type
4
Rhea-AI Filing Summary
Castle Biosciences CEO Derek J. Maetzold reported a mix of option exercises and share sales in Castle Biosciences Inc. common stock. He exercised stock options to acquire 6,214 shares at a price of $2.3900 per share and sold 9,836 shares in open-market transactions at a weighted-average price of $20.8570 per share.
Part of the sales came from entities such as The Maetzold Descendants 2020 Trust, the Derek Maetzold 2020 Irrevocable Trust and several 2018 remainder trusts, while a portion was from his direct holdings, which totaled 21,479 shares after these transactions. All sales were executed under a pre-arranged Rule 10b5-1 trading plan adopted on December 3, 2025.
Positive
- None.
Negative
- None.
Insider Trade Summary 10b5-1
Net Seller: 9,836 shares ($205,149)
Net Sell
14 txns
Insider
MAETZOLD DEREK J
Role
Pres. & Chief Exec. Officer
Sold
9,836 shs ($205K)
| Type | Security | Shares | Price | Value |
|---|---|---|---|---|
| Exercise | Stock option (right to buy) | 204 | $0.00 | -- |
| Exercise | Stock option (right to buy) | 6,010 | $0.00 | -- |
| Exercise | Common Stock | 204 | $2.39 | $487.56 |
| Exercise | Common Stock | 6,010 | $2.39 | $14K |
| Sale | Common Stock | 6,214 | $20.857 | $130K |
| Sale | Common Stock | 1,357 | $20.857 | $28K |
| Sale | Common Stock | 1,153 | $20.857 | $24K |
| Sale | Common Stock | 278 | $20.857 | $6K |
| Sale | Common Stock | 278 | $20.857 | $6K |
| Sale | Common Stock | 278 | $20.857 | $6K |
| Sale | Common Stock | 278 | $20.857 | $6K |
| holding | Common Stock | -- | -- | -- |
| holding | Common Stock | -- | -- | -- |
| holding | Common Stock | -- | -- | -- |
Holdings After Transaction:
Stock option (right to buy) — 0 shares (Direct, null);
Common Stock — 21,683 shares (Direct, null);
Common Stock — 43,424 shares (Indirect, By The Maetzold Descendants 2020 Trust)
Footnotes (1)
- These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on December 3, 2025. This transaction was executed in multiple trades at prices ranging from $20.470 to $21.175, 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. The shares subject to the option are fully vested.
Key Figures
Shares sold: 9,836 shares
Weighted-average sale price: $20.8570 per share
Sale price range: $20.470–$21.175 per share
+4 more
7 metrics
Shares sold
9,836 shares
Common stock sold in open-market transactions on June 1, 2026
Weighted-average sale price
$20.8570 per share
Open-market sales of CSTL common stock
Sale price range
$20.470–$21.175 per share
Price range of multiple trades aggregated into reported average
Options exercised
6,214 shares
Stock options converted into common shares on June 1, 2026
Option exercise price
$2.3900 per share
Exercise price for stock options converted into common stock
Direct common shares after trades
21,479 shares
Derek Maetzold’s direct CSTL holdings following reported transactions
Descendants 2020 Trust holdings
43,424 shares
Common stock held by The Maetzold Descendants 2020 Trust after sales
Key Terms
Rule 10b5-1 plan, Grantor Retained Annuity Trust, Irrevocable Trust, Stock option (right to buy), +1 more
5 terms
Rule 10b5-1 plan regulatory
"These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on December 3, 2025."
A Rule 10b5-1 plan is a prearranged, written schedule that lets corporate insiders buy or sell company stock at set times or amounts, even if they later learn material nonpublic information. Think of it like setting an automatic thermostat for trades: it creates a clear record that trades were planned in advance, reducing the risk of insider-trading accusations and helping investors trust that insider transactions are routine rather than based on secret information.
Grantor Retained Annuity Trust financial
"Held by DJM Grantor Retained Annuity Trust No. 5 of which the Reporting Person is the trustee and beneficiary."
A grantor retained annuity trust (GRAT) is an estate-planning tool where the person who creates the trust transfers assets into it but receives fixed cash payments (an annuity) from the trust for a set number of years; whatever remains after that term passes to designated beneficiaries. It matters to investors because it can shift future appreciation of assets out of the creator’s taxable estate—like putting an asset into a timed vending machine that pays you fixed amounts while any extra value that grows inside the machine goes to heirs with reduced gift or estate tax consequences.
Irrevocable Trust financial
"Held by Derek Maetzold 2020 Irrevocable Trust of which the Reporting Person is the trustee and his children are beneficiaries."
An irrevocable trust is a legal arrangement where an owner transfers assets into a separate entity managed by a trustee and gives up the power to modify or reclaim those assets. For investors it matters because putting stock or other holdings into such a trust can change who controls and benefits from the assets, affect taxes and creditor protection, and influence how easy it is to sell or value those holdings—like placing valuables in a locked safe overseen by someone else.
Stock option (right to buy) financial
"Stock option (right to buy) with underlying security title Common Stock and exercise price of $2.3900."
weighted-average sale price financial
"The price reported above reflects the weighted-average sale price."
FAQ
What insider transactions did CSTL CEO Derek Maetzold report?
Derek Maetzold reported exercising stock options and selling Castle Biosciences (CSTL) shares. He exercised 6,214 options at $2.3900 per share and sold 9,836 common shares at a weighted-average price of $20.8570 per share in open-market trades.
What stock options did the CSTL CEO exercise in this Form 4?
Derek Maetzold exercised stock options covering 6,214 Castle Biosciences common shares. The options had an exercise price of $2.3900 per share and were fully vested. After these exercises, no remaining derivative positions related to these options are shown in the filing.