Kastelein Johannes Jacob Pieter — SEC Form 4 filings
SEC reporting owner CIK 2000389. 10 Form 4 filings on record with FilingPulse; latest filed 2026-08-25.
Transaction summary — filings shown
Covers all 10 filings on record, filed 2024-03-27 to 2026-08-25. Counts and totals are arithmetic on values as filed — descriptive data, not a recommendation.
- Open-market purchases (code P, non-derivative): none reported.
- Open-market sales (code S, non-derivative): 11 legs across 6 filings — 766,957 shares, $20,826,990 total (shares × price as filed).
- Other reported legs (grants, option exercises, tax withholding, gifts, derivative-security transactions, …): 21.
- Largest priced transaction: sale of 190,476 shares @ $21.50 ($4,095,234) in NewAmsterdam Pharma Co N.V., filed 2024-03-27.
By issuer — same filings
Open-market purchase/sale legs on non-derivative securities, grouped by issuer. Role is as filed on the newest filing for that issuer. Dollar totals cover priced legs only (shares × price as filed). Ordered by priced transaction value, largest first.
| Issuer | Role (as filed) | Filings | Purchases (P) | Sales (S) | Other legs |
|---|---|---|---|---|---|
| NewAmsterdam Pharma Co N.V. (NAMS) | Chief Scientific Officer, Director | 10 | — | 11 legs · 766,957 sh · $20,826,990 | 21 |
Form 4 filings — Kastelein Johannes Jacob Pieter
| Filed | Form | Issuer | Reported transactions | Source |
|---|---|---|---|---|
| 2026-08-25 | 4 | NewAmsterdam Pharma Co N.V. (NAMS) | Option exercise (M): 125,000 · Sale (S): 125,000 @ $26.91 · Option exercise (M): 125,000 (derivative) @ $0 | EDGAR |
| 2026-03-09 | 4 | NewAmsterdam Pharma Co N.V. (NAMS) | Option exercise (M): 104,467 · Sale (S): 104,467 @ $30.30 · Option exercise (M): 94,124 · Sale (S): 94,124 @ $30.32 · Option exercise (M): 101,409 · Sale (S): 101,409 @ $30.29 · +3 more | EDGAR |
| 2026-02-24 | 4 | NewAmsterdam Pharma Co N.V. (NAMS) | Sale (S): 14,692 @ $35 · Sale (S): 30,789 @ $35.46 | EDGAR |
| 2026-01-07 | 4 | NewAmsterdam Pharma Co N.V. (NAMS) | Sale (S): 6,000 @ $33.25 · Grant/award (A): 25,500 · Grant/award (A): 115,000 (derivative) @ $0 | EDGAR |
| 2025-08-25 | 4 | NewAmsterdam Pharma Co N.V. (NAMS) | Sale (S): 50,000 @ $24.29 · Sale (S): 42,342 @ $25.08 · Sale (S): 7,658 @ $25.49 | EDGAR |
| 2025-03-28 | 4 | NewAmsterdam Pharma Co N.V. (NAMS) | Grant/award (A): 19,302 @ $0 · Option exercise (M): 45,481 @ $0 · Grant/award (A): 45,481 (derivative) · Option exercise (M): 45,481 (derivative) | EDGAR |
| 2025-03-26 | 4 | NewAmsterdam Pharma Co N.V. (NAMS) | Option exercise (M): 150,000 · Option exercise (M): 150,000 (derivative) @ $0 | EDGAR |
| 2025-01-07 | 4 | NewAmsterdam Pharma Co N.V. (NAMS) | Grant/award (A): 34,000 | EDGAR |
| 2025-01-06 | 4 | NewAmsterdam Pharma Co N.V. (NAMS) | Grant/award (A): 200,000 (derivative) @ $0 | EDGAR |
| 2024-03-27 | 4 | NewAmsterdam Pharma Co N.V. (NAMS) | Option exercise (M): 201,673 · Tax withholding (F): 11,197 @ $22.72 · Sale (S): 190,476 @ $21.50 · Option exercise (M): 201,673 (derivative) @ $0 | EDGAR |
FilingPulse's Form 4 archive currently extends back to 2024-01-11 and is expanding backward through EDGAR history — earlier filings by this insider may not be indexed yet. Names and roles are shown as filed.
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