Form 4 for CSTL CASTLE BIOSCIENCES INC
Accepted 2026-03-05 00:00:00 ET · period of report 2026-03-03 · accession 0001628280-26-015344 · SEC index · Original document
Summary rows
Aggregated the way they appear in lists: one row per insider, transaction code and security table.
| X | Filed | Traded | Ticker | Insider | Title | Type | Price | Qty | Owned | ΔOwn | Value |
|---|---|---|---|---|---|---|---|---|---|---|---|
| D | 2026-03-05 | 2026-03-04 | CSTL | MAETZOLD DEREK J | Pres, Chief Exec. Off, Dir | M - OptEx | — | +59.1K | 123.8K | +91% | — |
| DM | 2026-03-05 | 2026-03-03+ | CSTL | MAETZOLD DEREK J | Pres, Chief Exec. Off, Dir | F - Tax | $27.86 | -37.0K | 105.8K | -26% | -$1.03M |
| DM | 2026-03-05 | 2026-03-04 | CSTL | MAETZOLD DEREK J | Pres, Chief Exec. Off, Dir | M - OptEx | $0.00 | -59.1K | 84.0K | -41% | $0 |
| D | 2026-03-05 | 2026-03-03 | CSTL | MAETZOLD DEREK J | Pres, Chief Exec. Off, Dir | A - Grant | $0.00 | +102.6K | 102.6K | New | $0 |
Every reported transaction
| # | Table | Security | Date | Code | A/D | Shares | Price | Owned after | Own | Exercise / expiry | Underlying | Footnotes |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | Common | Common Stock | 2026-03-04 | M | A | 59,097 | — | 123,752 | D | — | — | (F2) Each Restricted Stock Unit ("RSU") represents the right to receive one share of the Issuer's Common Stock. |
| 2 | Common | Common Stock | 2026-03-03 | F | D | 19,043 | $27.57 | 64,655 | D | — | — | (F1) Reflects the withholding of shares of the Issuer's common stock to satisfy tax withholding obligations in connection with the delivery of vested performance stock units reported on January 12, 2026. |
| 3 | Common | Common Stock | 2026-03-04 | F | D | 17,931 | $28.17 | 105,821 | D | — | — | |
| 4 | Derivative | Restricted Stock Units | 2026-03-04 | M | D | 31,110 | $0.00 | 62,218 | D | — · — to — | 31,110 Common Stock | (F2) Each Restricted Stock Unit ("RSU") represents the right to receive one share of the Issuer's Common Stock. (F13) On March 4, 2024, the Reporting Person was granted 124,437 RSUs which vest in four equal installments beginning on March 4, 2025. |
| 5 | Derivative | Restricted Stock Units | 2026-03-04 | M | D | 27,987 | $0.00 | 83,961 | D | — · — to — | 27,987 Common Stock | (F2) Each Restricted Stock Unit ("RSU") represents the right to receive one share of the Issuer's Common Stock. (F14) On March 4, 2025, the Reporting Person was granted 111,948 RSUs which vest in four equal installments beginning on March 4, 2026. |
| 6 | Derivative | Restricted Stock Units | 2026-03-03 | A | A | 102,597 | $0.00 | 102,597 | D | — · — to — | 102,597 Common Stock | (F2) Each Restricted Stock Unit ("RSU") represents the right to receive one share of the Issuer's Common Stock. (F12) The RSU's vest in four equal annual installments beginning on March 03, 2027. |