Form 4 for CSTL CASTLE BIOSCIENCES INC
Accepted 2026-09-03 16:07:34 ET · period of report 2026-09-01 · accession 0001628280-26-060430 · 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| DT | 2026-09-03 16:07 | 2026-09-01 | CSTL | Oelschlager Kristen M | COO | M - OptEx | $3.38 | +4,152 | 17.5K | +31% | +$14.0K |
| DMT | 2026-09-03 16:07 | 2026-09-01 | CSTL | Oelschlager Kristen M | COO | S - Sale+OE | $33.39 | -4,152 | 13.4K | -24% | -$138.6K |
| DT | 2026-09-03 16:07 | 2026-09-01 | CSTL | Oelschlager Kristen M | COO | M - OptEx | $0.00 | -4,152 | 12.5K | -25% | $0 |
Purchase Sale Sale after option exercise All abbreviations
Every reported transaction
| # | Table | Security | Date | Code | A/D | Shares | Price | Owned after | Own | Exercise / expiry | Underlying | Footnotes |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | Common | Common Stock | 2026-09-01 | M | A | 4,152 | $3.38 | 17,508 | D | — | — | (F1) These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person, on March 17, 2026. (F2) Includes 68 shares acquired on August 31, 2026, under the Issuer's employee stock purchase plan. |
| 2 | Common | Common Stock | 2026-09-01 | S | D | 3,952 | $33.36 | 13,556 | D | — | — | (F1) These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person, on March 17, 2026. (F3) This transaction was executed in multiple trades at prices ranging from $33.015 to $33.900, 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. |
| 3 | Common | Common Stock | 2026-09-01 | S | D | 200 | $34.02 | 13,356 | D | — | — | (F1) These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person, on March 17, 2026. |
| 4 | Derivative | Stock option (right to buy) | 2026-09-01 | M | D | 4,152 | $0.00 | 12,458 | D | $3.38 · — to 2029-03-12 | 4,152 Common Stock | (F1) These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person, on March 17, 2026. (F5) The shares subject to the option are fully vested. |