Castle Biosciences (CSTL) CEO pre-planned sale of 9,836 shares after option exercise
Filing Impact
Filing Sentiment
Form Type
4
Rhea-AI Filing Summary
CASTLE BIOSCIENCES INC President & CEO Derek J. Maetzold reported an exercise-and-sell transaction in company stock. On April 6, 2026, he exercised stock options to acquire 6,214 shares of common stock at an exercise price of $2.39 per share, converting previously granted options into shares.
On the same date, Maetzold sold 6,214 directly held shares of common stock at a weighted-average price of about $25.03 per share, along with additional open-market sales through several family and estate-planning trusts totaling 9,836 shares sold overall. According to the filing, these sales were made under a Rule 10b5-1 trading plan adopted on December 3, 2025, indicating they were pre-scheduled rather than opportunistic trades.
After these transactions, Maetzold continues to hold 21,479 shares directly and maintains substantial indirect ownership through multiple trusts, including 48,852 shares in The Maetzold Descendants 2020 Trust and 85,959 shares in DJM Grantor Retained Annuity Trust No. 5, among other vehicles.
Positive
- None.
Negative
- None.
Insider Trade Summary 10b5-1
Net Seller: 9,836 shares ($246,195)
Net Sell
12 txns
Insider
MAETZOLD DEREK J
Role
Pres. & Chief Exec. Officer
Sold
9,836 shs ($246K)
| Type | Security | Shares | Price | Value |
|---|---|---|---|---|
| Exercise | Stock option (right to buy) | 6,214 | $0.00 | -- |
| Exercise | Common Stock | 6,214 | $2.39 | $15K |
| Sale | Common Stock | 6,214 | $25.03 | $156K |
| Sale | Common Stock | 1,357 | $25.03 | $34K |
| Sale | Common Stock | 1,153 | $25.03 | $29K |
| Sale | Common Stock | 278 | $25.03 | $7K |
| Sale | Common Stock | 278 | $25.03 | $7K |
| Sale | Common Stock | 278 | $25.03 | $7K |
| Sale | Common Stock | 278 | $25.03 | $7K |
| holding | Common Stock | -- | -- | -- |
| holding | Common Stock | -- | -- | -- |
| holding | Common Stock | -- | -- | -- |
Holdings After Transaction:
Stock option (right to buy) — 7,518 shares (Direct);
Common Stock — 27,693 shares (Direct);
Common Stock — 48,852 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 $24.64 to $25.29, 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
Options exercised: 6,214 shares
Exercise price: $2.39 per share
Direct shares sold: 6,214 shares
+5 more
8 metrics
Options exercised
6,214 shares
Stock option exercise at $2.39 on April 6, 2026
Exercise price
$2.39 per share
Strike price of stock option exercised for 6,214 shares
Direct shares sold
6,214 shares
Common stock sold at weighted-average $25.03 per share
Total shares sold
9,836 shares
Aggregate open-market sales including trust-held shares
Sale price
$25.03 per share
Weighted-average price for CSTL common stock sales
Direct holdings after trade
21,479 shares
Common stock directly owned by Maetzold post-transaction
Descendants 2020 Trust holdings
48,852 shares
CSTL common stock held by The Maetzold Descendants 2020 Trust
GRAT No. 5 holdings
85,959 shares
CSTL common stock held by DJM Grantor Retained Annuity Trust No. 5
Key Terms
Rule 10b5-1 plan, weighted-average sale price, Grantor Retained Annuity 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..."
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.
weighted-average sale price financial
"executed in multiple trades at prices ranging... The price reported above reflects the weighted-average sale price."
Grantor Retained Annuity Trust financial
"Held by DJM Grantor Retained Annuity Trust No. 5 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.
stock option (right to buy) financial
"security_title": "Stock option (right to buy)""
open-market sale financial
"transaction_action": "open-market sale""
An open-market sale is when a shareholder sells existing shares directly on a public exchange to any willing buyer, rather than through a private deal. Think of it like putting goods on a busy market stall where price is set by supply and demand; for investors it matters because such sales increase available supply, can put short-term downward pressure on the stock price, and signal changes in liquidity or investor confidence.
FAQ
What insider transactions did CSTL CEO Derek Maetzold report on April 6, 2026?
He exercised stock options for 6,214 shares at $2.39 and sold a total of 9,836 shares of Castle Biosciences (CSTL) common stock at around $25.03 per share, including direct and trust-held shares.
What happened to Derek Maetzold’s CSTL stock options in this Form 4 filing?
He exercised fully vested options covering 6,214 shares at an exercise price of $2.39 per share. After this exercise, there are no remaining options from that grant, and the acquired shares were then sold in open-market transactions reported in the same filing.