Johannes Jacob Pieter Kastelein serves as Executive at NewAmsterdam Pharma Co N.V., where they oversee executive responsibilities. Since joining the company, Johannes Jacob Pieter Kastelein has executed 9 insider transactions totaling $6.8M, demonstrating a bearish approach to their equity position. Their most recent transaction on Jan 7, 2026 involved receiving (via award) 115,000 shares valued at $0.
Johannes Jacob Pieter Kastelein currently holds 115,000 shares of NewAmsterdam Pharma Co N.V. (NAMS), valued at approximately $0. This represents their equity stake as Executive.
Based on SEC Form 4 filings, Johannes Jacob Pieter Kastelein has been a net seller of NAMS stock. They have purchased $0 and sold $6.8M worth of shares.
Johannes Jacob Pieter Kastelein's most recent insider trade was on Jan 7, 2026, when they sold 115,000 shares at $0.00 per share.
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| $N/A |
| Discretionary |
| Jan 5, 2026 | NAMS | $199.5K | Sale | 6,000 | $33.25 | Discretionary |
| Aug 22, 2025 | NAMS | $1.1M | Sale | 42,342 | $25.08 | Discretionary |
| Aug 22, 2025 | NAMS | $195.2K | Sale | 7,658 | $25.49 | Discretionary |
| Aug 21, 2025 | NAMS | $1.2M | Sale | 50,000 | $24.29 | Discretionary |
| Mar 26, 2024 | NAMS | $0 | Option Exercise | 201,673 | $N/A | Discretionary |
| Mar 26, 2024 | NAMS | $254.4K | Payment | 11,197 | $22.72 | Discretionary |
| Mar 26, 2024 | NAMS | $4.1M | Sale | 190,476 | $21.50 | Discretionary |