Castle Biosciences (CSTL) CEO Maetzold exercises options, trusts sell 4,172 shares
Filing Impact
Filing Sentiment
Form Type
4
Rhea-AI Filing Summary
CASTLE BIOSCIENCES INC director and CEO Derek J. Maetzold reported a mix of option exercises and pre-planned share sales involving his direct and trust-related holdings. He exercised stock options to acquire 550 shares of common stock at $2.39 per share, increasing his direct holdings before selling shares.
Entities associated with him, including several 2018 and 2020 family trusts, sold a combined 4,172 shares of common stock in open-market transactions at a weighted-average price of $20.66 per share. These sales were carried out under a Rule 10b5-1 trading plan adopted on December 3, 2025, indicating the trades were pre-scheduled. Following the transactions, Maetzold holds 21,479 shares directly and various additional indirect positions through multiple grantor retained annuity and remainder trusts.
Positive
- None.
Negative
- None.
Insider Trade Summary 10b5-1
Net Seller: 4,172 shares ($86,194)
Net Sell
12 txns
Insider
MAETZOLD DEREK J
Role
Pres. & Chief Exec. Officer
Sold
4,172 shs ($86K)
| Type | Security | Shares | Price | Value |
|---|---|---|---|---|
| Exercise | Stock option (right to buy) | 550 | $0.00 | -- |
| Exercise | Common Stock | 550 | $2.39 | $1K |
| Sale | Common Stock | 550 | $20.66 | $11K |
| Sale | Common Stock | 1,357 | $20.66 | $28K |
| Sale | Common Stock | 1,153 | $20.66 | $24K |
| Sale | Common Stock | 278 | $20.66 | $6K |
| Sale | Common Stock | 278 | $20.66 | $6K |
| Sale | Common Stock | 278 | $20.66 | $6K |
| Sale | Common Stock | 278 | $20.66 | $6K |
| holding | Common Stock | -- | -- | -- |
| holding | Common Stock | -- | -- | -- |
| holding | Common Stock | -- | -- | -- |
Holdings After Transaction:
Stock option (right to buy) — 91,881 shares (Direct, null);
Common Stock — 22,029 shares (Direct, null);
Common Stock — 42,067 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 $20.44 to $20.98, 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. Reflects the transfers on June 10, 2026, of 45,024 shares of common stock from DJM Grantor Annuity Trust No. 5, of which, 11,256 transferred to The Maetzold 2018 Remainder Trust FBO Emily Carol Kirk, 11,256 transferred to The Maetzold 2018 Remainder Trust FBO Hannah Elizabeth Maetzold, 11,256 transferred to The Maetzold 2018 Remainder Trust FBO John Derek Maetzold and 11,256 transferred to The Maetzold 2018 Remainder Trust FBO Peter Douglas Maetzold. The remaining 40,935 shares of common stock held by DJM Grantor Annuity Trust No. 5 were transferred as described in footnote 12, after which DJM Grantor Annuity Trust No. 5 holds no remaining shares of common stock. 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. 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. Held by DJM Grantor Retained Annuity Trust No. 8 of which the Reporting Person is the trustee and beneficiary. On June 10, 2026, 40,935 shares of common stock were transferred from DJM Grantor Annuity Trust No. 5 to the Reporting Person's direct holdings, and subsequently transferred from the Reporting Person's direct holdings to DJM Grantor Retained Annuity Trust No. 8. The shares subject to the option are fully vested.
Key Figures
Shares sold: 4,172 shares
Sale price: $20.66/share
Options exercised: 550 shares
+5 more
8 metrics
Shares sold
4,172 shares
Total common shares sold across entities on June 15, 2026
Sale price
$20.66/share
Weighted-average price for open-market sales, trades $20.44–$20.98
Options exercised
550 shares
Stock option exercise into common stock on June 15, 2026
Option exercise price
$2.39/share
Exercise price for 550 stock option shares
Direct holdings after
21,479 shares
Maetzold’s direct Castle Biosciences common stock after transactions
Descendants 2020 Trust holdings
42,067 shares
Common stock held by The Maetzold Descendants 2020 Trust after sales
Irrevocable 2020 Trust holdings
35,755 shares
Common stock held by Derek Maetzold 2020 Irrevocable Trust after sales
Net share change
-4,172 shares
Net buy-sell shares across all reported transactions
Key Terms
Rule 10b5-1 plan, Grantor Retained Annuity Trust, stock option (right to buy), weighted-average sale price, +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. 6 of which the Reporting Person is the trustee and the beneficiaries are..."
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.
stock option (right to buy) financial
"Stock option (right to buy) ... Exercise or conversion of derivative security"
weighted-average sale price financial
"The price reported above reflects the weighted-average sale price."
derivative security financial
"Exercise or conversion of derivative security"
A derivative security is a financial contract whose value comes from the price or performance of something else, such as a stock, bond, commodity, or market index. For investors it acts like an insurance policy or a wager: it can be used to protect against losses, lock in prices, or amplify gains and losses, so it can change a portfolio’s risk and potential return without owning the underlying asset directly.
