Castle Biosciences CEO trades stock under plan
Castle Biosciences CEO Derek J. Maetzold exercised stock options for 6,214 shares of common stock at $2.39 per share and reported related sales totaling 9,836 common shares on July 27, 2026.
Rhea-AI Filing Summary
Castle Biosciences CEO Derek J. Maetzold exercised stock options for 6,214 shares of common stock at $2.39 per share and reported related sales totaling 9,836 common shares on July 27, 2026. Sales from direct holdings and several family trusts occurred at weighted-average prices of $24.13 and $25.06 per share, pursuant to a Rule 10b5-1 trading plan adopted on December 3, 2025. Following the option exercise, Maetzold held 78,903 options, and indirect holdings included 18,718, 44,323 and 40,935 common shares in three Grantor Retained Annuity Trusts.
Positive
- None.
Negative
- None.
Insider Trade Summary 10b5-1
Exercise and sale activity reported; no spread calculated
Exercise and Sale
19 txns
Insider
MAETZOLD DEREK J
Role
Pres. & Chief Exec. Officer
Sold
9,836 shs ($238K)
Approx. gross sale proceeds
$238K
Approx. exercise cost
$15K
| Type | Security | Shares | Price | Value |
|---|---|---|---|---|
| Exercise | Stock option (right to buy) F1, F13 | 6,214 | $0.00 | $0.00 |
| Exercise | Common Stock F1 | 6,214 | $2.39 | $15K |
| Sale | Common Stock F1, F2 | 5,982 | $24.13 | $144K |
| Sale | Common Stock F1, F2, F3 | 1,307 | $24.13 | $32K |
| Sale | Common Stock F1, F2, F4 | 1,110 | $24.13 | $27K |
| Sale | Common Stock F1, F2, F5 | 268 | $24.13 | $6K |
| Sale | Common Stock F1, F2, F6 | 268 | $24.13 | $6K |
| Sale | Common Stock F1, F2, F7 | 268 | $24.13 | $6K |
| Sale | Common Stock F1, F2, F8 | 268 | $24.13 | $6K |
| Sale | Common Stock F1, F9 | 232 | $25.06 | $6K |
| Sale | Common Stock F1, F9, F3 | 50 | $25.06 | $1K |
| Sale | Common Stock F1, F9, F4 | 43 | $25.06 | $1K |
| Sale | Common Stock F1, F9, F5 | 10 | $25.06 | $250.60 |
| Sale | Common Stock F1, F9, F6 | 10 | $25.06 | $250.60 |
| Sale | Common Stock F1, F9, F7 | 10 | $25.06 | $250.60 |
| Sale | Common Stock F1, F9, F8 | 10 | $25.06 | $250.60 |
| holding | Common Stock F10 | -- | -- | -- |
| holding | Common Stock F11 | -- | -- | -- |
| holding | Common Stock F12 | -- | -- | -- |
Holdings After Transaction:
Stock option (right to buy) — 78,903 contracts (Direct);
Common Stock — 21,479 shares (Direct);
Common Stock — 37,996 shares (Indirect, By The Maetzold Descendants 2020 Trust);
Common Stock — 32,296 shares (Indirect, By Derek Maetzold 2020 Irrevocable Trust);
Common Stock — 11,812 shares (Indirect, By The Maetzold 2018 Remainder Trust FBO Emily Carol Kirk);
Common Stock — 11,812 shares (Indirect, By The Maetzold 2018 Remainder Trust FBO Hannah Elizabeth Maetzold);
Common Stock — 11,812 shares (Indirect, By The Maetzold 2018 Remainder Trust FBO John Derek Maetzold);
Common Stock — 11,812 shares (Indirect, By The Maetzold 2018 Remainder Trust FBO Peter Douglas Maetzold);
Common Stock — 18,718 shares (Indirect, By DJM Grantor Retained Annuity Trust No. 6);
Common Stock — 44,323 shares (Indirect, By DJM Grantor Retained Annuity Trust No. 7);
Common Stock — 40,935 shares (Indirect, By DJM Grantor Retained Annuity Trust No. 8)
Footnotes (13)
- F1. These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on December 3, 2025.
- F2. This transaction was executed in multiple trades at prices ranging from $23.85 to $24.62, 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.
- F3. 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.
- F4. Held by Derek Maetzold 2020 Irrevocable Trust of which the Reporting Person is the trustee and his children are beneficiaries.
- F5. 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.
- F6. 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.
- F7. 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.
- F8. 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.
- F9. This transaction was executed in multiple trades at prices ranging from $24.97 to $25.11, 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.
- F10. 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.
- F11. Held by DJM Grantor Retained Annuity Trust No. 7 of which the Reporting Person is the trustee and beneficiary.
- F12. Held by DJM Grantor Retained Annuity Trust No. 8 of which the Reporting Person is the trustee and beneficiary.
- F13. The shares subject to the option are fully vested.
Key Figures
Options exercised: 6214.0000 shares
Option exercise price: 2.3900 $/share
Shares sold: 9836 shares
+5 more
8 metrics
Options exercised
6214.0000 shares
Stock options converted into common stock on 2026-07-27
Option exercise price
2.3900 $/share
Exercise price for 6,214-share stock option
Shares sold
9836 shares
Total common shares sold across reported transactions
Weighted-average sale price (group 1)
24.1300 $/share
Sales executed in trades ranging from $23.85 to $24.62
Weighted-average sale price (group 2)
25.0600 $/share
Sales executed in trades ranging from $24.97 to $25.11
Options remaining after exercise
78903.0000 shares
Stock options held following reported option exercise
Indirect holding Trust No. 6
18718.0000 shares
Common stock held by DJM Grantor Retained Annuity Trust No. 6
Indirect holding Trust No. 7
44323.0000 shares
Common stock held by DJM Grantor Retained Annuity Trust No. 7
Key Terms
Rule 10b5-1 plan, Grantor Retained Annuity Trust, weighted-average sale price, 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"
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"
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.
weighted-average sale price financial
"The price reported above reflects the weighted-average sale price"
Stock option (right to buy) financial
"security_title: Stock option (right to buy)"
indirect ownership financial
"nature_of_ownership: By The Maetzold Descendants 2020 Trust"
FAQ
AI-generated questions and answers. How Rhea-AI works. Not financial advice.
What insider transactions did CSTL CEO Derek Maetzold report on July 27, 2026?
Derek J. Maetzold reported exercising 6,214 Castle Biosciences shares via stock options at $2.39 and sales totaling 9,836 common shares. Sales came from direct holdings and several family trusts at weighted-average prices of $24.13 and $25.06 per share.
Were the CSTL insider trades by Derek Maetzold made under a Rule 10b5-1 plan?
Yes. The filing states the transactions were made pursuant to a Rule 10b5-1 plan adopted by Derek J. Maetzold on December 3, 2025. The document-level Rule 10b5‑1 checkbox is also affirmed, indicating these trades followed a pre-established trading arrangement.
What stock options did CSTL CEO Derek Maetzold exercise in this Form 4?
Maetzold exercised a stock option covering 6,214 Castle Biosciences shares at an exercise price of $2.39 per share. The option, fully vested and expiring on May 9, 2028, left him with 78,903 options remaining after the reported exercise.
What indirect Castle Biosciences (CSTL) holdings are reported through Maetzold family trusts?
Indirect CSTL holdings include 18,718 shares in DJM Grantor Retained Annuity Trust No. 6, 44,323 shares in Trust No. 7, and 40,935 shares in Trust No. 8. The filing notes Derek J. Maetzold serves as trustee and, in some trusts, also beneficiary.
AI-generated analysis. How Rhea-AI works. Not financial advice.
