Kastelein Johannes Jacob Pieter insider trades
Kastelein Johannes Jacob Pieter has filed 11 Form 4s with the SEC that we hold, all for NewAmsterdam Pharma Co N.V. (NAMS), as Chief Scientific Officer, Director. Across all of them we count 0 purchases worth $0 and 11 sales worth $18.7M reported on Form 4. In the last 12 months: 0 purchases ($0) and 7 sales ($12.2M). The largest single trade was a sale of 190,476 shares of NewAmsterdam Pharma Co N.V. worth $4.1M, dated 2024-03-26. Of 1 sale filed since we began reading the 10b5-1 checkbox, 1 (100%) was marked as made under a 10b5-1 trading plan. The first filing on our record is dated 2024-01-03 and the latest 2026-10-02.
NewAmsterdam Pharma Co N.V. (NAMS)
| Trade date | Code | Shares | Value as filed | Filed |
|---|---|---|---|---|
| 2024-03-26 | S, sale reported on Form 4 | 190,476 | $4.1M | 2024-03-27 |
| 2025-08-21 | S, sale reported on Form 4 | 50,000 | $1.2M | 2025-08-25 |
| 2025-08-22 | S, sale reported on Form 4 | 7,658 | $195.2K | 2025-08-25 |
| 2025-08-22 | S, sale reported on Form 4 | 42,342 | $1.1M | 2025-08-25 |
| 2026-01-05 | S, sale reported on Form 4 | 6,000 | $199.5K | 2026-01-07 |
| 2026-02-20 | S, sale reported on Form 4 | 30,789 | $1.1M | 2026-02-24 |
| 2026-02-20 | S, sale reported on Form 4 | 14,692 | $514.2K | 2026-02-24 |
| 2026-03-05 | S, sale reported on Form 4 | 104,467 | $3.2M | 2026-03-09 |
| 2026-03-06 | S, sale reported on Form 4 | 94,124 | $2.9M | 2026-03-09 |
| 2026-03-09 | S, sale reported on Form 4 | 101,409 | $3.1M | 2026-03-09 |
| 2026-09-30 | S, sale reported on Form 4 | 50,246 | $1.3M | 2026-10-02 |
Counted from the Form 4 filings this reporting owner (SEC CIK 2000389) filed on EDGAR. Values are the transaction values as filed. See every filing on EDGAR, or browse insider buying and today's insider purchases.
Source: U.S. Securities and Exchange Commission (EDGAR) and other official
government data · Updated 2026-10-12 ·
For informational purposes only, not investment advice.
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