Johannes Jacob Pieter Kastelein
Chief Scientific Officer, Director · NewAmsterdam Pharma Co N.V.
IndividualSelling only15 10b5-1 trades
- 2025
- Oct 2, 2026
- 6
Chief Scientific Officer, Director · NewAmsterdam Pharma Co N.V.
Latest filing:
Johannes Jacob Pieter Kastelein is Chief Scientific Officer, Director of NewAmsterdam Pharma Co N.V. (NAMS). 6 SEC Form 4 filings on record going back to 2025, most recently on 2 October 2026. Most recent open-market trade: sold $1.26M of NAMS on 2 October 2026. Lifetime open-market sales: $17.99M.
The latest 17 SEC Form 4 transactions reported by Johannes Jacob Pieter Kastelein.
Insiders who reported open-market trades in the last 12 months at the companies Johannes Jacob Pieter Kastelein files at. Multiple unrelated insiders buying the same stock within a short window, cluster buying, has historically been one of the strongest Form 4 signals.
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Johannes Jacob Pieter Kastelein is a corporate insider, tracked as Chief Scientific Officer, Director of NewAmsterdam Pharma Co N.V. (NAMS). InsiderAlpha holds 6 primary Form 4 filings for them, the earliest from 2025, updated as new SEC EDGAR filings are processed.
2 primary Form 4 filings in the last 90 days, covering 1 company.
Recorded transactions: 0 open-market purchases and 11 open-market sales ($17.99M) across all tracked filings.
InsiderAlpha's records for Johannes Jacob Pieter Kastelein go back to 2025: 6 primary Form 4 filings, an average of 3.0 per year. 15 recorded transactions carry a Rule 10b5-1 plan flag. This identifies the marked transactions as reported under a trading plan; it does not establish the plan status of unmarked transactions.
