SEC Form 4 · accession 0001628280-26-054334
CASTLE BIOSCIENCES INC · CSTL
Statement of changes in beneficial ownership, as filed. Original on EDGAR ↗
Reporting owner
Derek J Maetzold
Officer — Pres. & Chief Exec. Officer · Director
Period of report
Aug 4, 2026
Accepted (ET)
Aug 6, 2026 · 4:14 pm EDT
Rule 10b5-1 plan
yes — trade under a plan
Issuer CIK
0001447362
Table I — non-derivative securities
| Security | Date | Code | Shares | Price | A/D | Owned after | D/I | Nature of ownership |
|---|---|---|---|---|---|---|---|---|
| Common Stock | Aug 4, 2026 | M | 20,356 | $2.39 | A | 41,835 | D | |
| Common StockF2 | Aug 4, 2026 | S | 8,421 | $30.788 | D | 33,414 | D | |
| Common StockF2,F3 | Aug 4, 2026 | S | 3,374 | $30.788 | D | 28,407 | I | By The Maetzold Descendants 2020 Trust |
| Common StockF2,F4 | Aug 4, 2026 | S | 2,866 | $30.788 | D | 24,143 | I | By Derek Maetzold 2020 Irrevocable Trust |
| Common StockF5 | Aug 4, 2026 | S | 11,935 | $31.336 | D | 21,479 | D | |
| Common StockF5,F3 | Aug 4, 2026 | S | 4,782 | $31.336 | D | 23,625 | I | By The Maetzold Descendants 2020 Trust |
| Common StockF5,F4 | Aug 4, 2026 | S | 4,063 | $31.336 | D | 20,080 | I | By Derek Maetzold 2020 Irrevocable Trust |
| Common Stock | Aug 5, 2026 | M | 2,546 | $2.39 | A | 24,025 | D | |
| Common StockF6 | Aug 5, 2026 | S | 2,546 | $30.681 | D | 21,479 | D | |
| Common StockF6,F3 | Aug 5, 2026 | S | 556 | $30.681 | D | 23,069 | I | By The Maetzold Descendants 2020 Trust |
| Common StockF6,F4 | Aug 5, 2026 | S | 473 | $30.681 | D | 19,607 | I | By Derek Maetzold 2020 Irrevocable Trust |
| Common StockF7 | holding | — | — | — | 11,812 | I | By The Maetzold 2018 Remainder Trust FBO Emily Carol Kirk | |
| Common StockF8 | holding | — | — | — | 11,812 | I | By The Maetzold 2018 Remainder Trust FBO Hannah Elizabeth Maetzold | |
| Common StockF9 | holding | — | — | — | 11,812 | I | By The Maetzold 2018 Remainder Trust FBO John Derek Maetzold | |
| Common StockF10 | holding | — | — | — | 11,812 | I | By The Maetzold 2018 Remainder Trust FBO Peter Douglas Maetzold | |
| Common StockF11 | holding | — | — | — | 11,963 | I | By DJM Grantor Retained Annuity Trust No. 6 | |
| Common StockF12 | holding | — | — | — | 27,862 | I | By DJM Grantor Retained Annuity Trust No. 7 | |
| Common StockF13 | holding | — | — | — | 40,935 | I | By DJM Grantor Retained Annuity Trust No. 8 | |
| Common StockF14 | holding | — | — | — | 23,216 | I | DJM Grantor Retained Annuity Trust No. 9 |
Table II — derivative securities
| Security | Conv. / exercise price | Date | Code | Shares | A/D | Exercisable | Expires | Underlying | Underlying shares | Owned after | D/I |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Stock option (right to buy)F15 | $2.39 | Aug 4, 2026 | M | 20,356 | D | — | May 9, 2028 | Common Stock | 20,356 | 41,403 | D |
| Stock option (right to buy)F15 | $2.39 | Aug 5, 2026 | M | 2,546 | D | — | May 9, 2028 | Common Stock | 2,546 | 38,857 | D |
Explanation of responses
- F1These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on December 3, 2025.
- F10Held by The Maetzold 2018 Remainder Trust FBO Peter Douglas Maetzold of which the Reporting Person is the trustee and his child is the beneficiary.
- F11Held 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.
- F12Held by DJM Grantor Retained Annuity Trust No. 7 of which the Reporting Person is the trustee and beneficiary.
- F13Held by DJM Grantor Retained Annuity Trust No. 8 of which the Reporting Person is the trustee and beneficiary.
- F14Held by DJM Grantor Retained Annuity Trust No. 9 of which the Reporting Person is the trustee and beneficiary.
- F15The shares subject to the option are fully vested.
- F2This transaction was executed in multiple trades at prices ranging from $30.000 to $30.995, 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.
- F3Held 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.
- F4Held by Derek Maetzold 2020 Irrevocable Trust of which the Reporting Person is the trustee and his children are beneficiaries.
- F5This transaction was executed in multiple trades at prices ranging from $31.010 to $31.650, 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.
- F6This transaction was executed in multiple trades at prices ranging from $30.400 to $31.175, 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.
- F7Held by The Maetzold 2018 Remainder Trust FBO Emily Carol Kirk of which the Reporting Person is the trustee and his child is the beneficiary.
- F8Held by The Maetzold 2018 Remainder Trust FBO Hannah Elizabeth Maetzold of which the Reporting Person is the trustee and his child is the beneficiary.
- F9Held by The Maetzold 2018 Remainder Trust FBO John Derek Maetzold of which the Reporting Person is the trustee and his child is the beneficiary.