Updated Jul 16, 2026 · Last SEC filing 2026-07-06
CASTLE BIOSCIENCES INC (CSTL) has filed 23 SEC Form 4 insider transactions in the last 90 days, with the most recent on 2026-07-06. 2 Form 8-K material event filings were reported by CSTL in the last 90 days. 4 Form 144 notices of proposed sale were filed for CSTL stock. InsiderAlpha tracks every CSTL SEC filing — Form 4, Form 144, and 8-K — in real time, including Rule 10b5-1 plan detection.
| SIC classification | Services-Medical Laboratories (SIC 8071) |
|---|---|
| SEC CIK | 0001447362 |
| Form 4 filings (90d) | 23 |
|---|---|
| Form 8-K filings (90d) | 2 |
| Form 144 notices (90d) | 4 |
| Latest Form 4 filing | 2026-07-06 |
| Date | Insider | Role | Transaction | Shares | Price | Value | Filing |
|---|---|---|---|---|---|---|---|
| MAETZOLD DEREK J | Pres. & Chief Exec. Officer | S — Open-market sale | 6.2K | $24.29 | $151K | SEC | |
| MAETZOLD DEREK J | Pres. & Chief Exec. Officer | M — Option exercise | 6.2K | $2.39 | $15K | SEC | |
| MAETZOLD DEREK J | Pres. & Chief Exec. Officer | S — Open-market sale | 278 | $24.29 | $7K | SEC | |
| MAETZOLD DEREK J | Pres. & Chief Exec. Officer | S — Open-market sale | 1.4K | $24.29 | $33K | SEC | |
| MAETZOLD DEREK J | Pres. & Chief Exec. Officer | S — Open-market sale | 278 | $24.29 | $7K | SEC | |
| MAETZOLD DEREK J | Pres. & Chief Exec. Officer | S — Open-market sale | 1.2K | $24.29 | $28K | SEC | |
| MAETZOLD DEREK J | Pres. & Chief Exec. Officer | S — Open-market sale | 278 | $24.29 | $7K | SEC | |
| MAETZOLD DEREK J | Pres. & Chief Exec. Officer | S — Open-market sale | 278 | $24.29 | $7K | SEC | |
| Oelschlager Kristen M | Chief Operating Officer | S — Open-market sale | 8.2K | $24.40 | $200K | SEC | |
| Oelschlager Kristen M | Chief Operating Officer | S — Open-market sale | 400 | $24.78 | $10K | SEC | |
| Oelschlager Kristen M | Chief Operating Officer | S — Open-market sale | 8.6K | $20.71 | $178K | SEC | |
| MAETZOLD DEREK J | Pres. & Chief Exec. Officer | S — Open-market sale | 278 | $20.66 | $6K | SEC | |
| MAETZOLD DEREK J | Pres. & Chief Exec. Officer | S — Open-market sale | 550 | $20.66 | $11K | SEC | |
| MAETZOLD DEREK J | Pres. & Chief Exec. Officer | M — Option exercise | 550 | $2.39 | $1K | SEC | |
| MAETZOLD DEREK J | Pres. & Chief Exec. Officer | S — Open-market sale | 1.4K | $20.66 | $28K | SEC |
All transactions sourced from SEC EDGAR Form 4 filings for CASTLE BIOSCIENCES INC (CSTL). Updated in real time as new filings are submitted to the SEC.
| Insider | Form 4 filings | Total transaction value |
|---|---|---|
| MAETZOLD DEREK J | 72 | $985K |
| Oelschlager Kristen M | 3 | $387K |
| BRADBURY DANIEL | 3 | — |
| Cole G Bradley | 3 | — |
| Cotton Rodney | 3 | — |
Form 144 must be filed before insiders sell restricted or control stock above SEC thresholds. A cluster of Form 144 notices often precedes a wave of insider distribution.
SEC Form 4 transactions are reported with a one-letter code indicating the type of transaction. Common codes you'll see in CSTL insider filings:
| P | Open-market purchase by the insider |
|---|---|
| S | Open-market sale by the insider |
| A | Grant, award, or other acquisition from the issuer |
| M | Exercise or conversion of derivative security (e.g. options) |
| F | Payment of exercise price or tax liability via share withholding |
| G | Bona-fide gift of securities |
| D | Disposition to the issuer (e.g. share buyback participation) |
| J | Other acquisition or disposition |
| X | Exercise of in-the-money or at-the-money derivative security |
| C | Conversion of derivative security |
| V | Transaction voluntarily reported earlier than required |
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