Johannes Jacob Pieter Kastelein sold $1.3M of NAMS
Chief Scientific Officer at NewAmsterdam Pharma Co N.V.. 50,246 shares at an average of $25.03, traded Sep 30, 2026, filed Oct 2, 2026.
Score components
- +15RoleOfficer
- +25Trade size$1.3M at market
- +10Share of holdings soldSold 42% of holdings
- 0ClusterNo other insider selling within 14 days
- -15Exercise and sellShares came from an option exercise in the same filing
- -2010b5-1 planPre-scheduled under a 10b5-1 plan
What happened after comparable sells
Same side and tier, against the S&P 500, at 1, 3 and 6 months. Shown to Pro users; the whole table is on the backtest page.
Price around the trade, and since
From a quarter before the trade to today. The arrow is the trade, the circle the day the filing reached EDGAR, which is the first day anyone outside could act; the dotted line is the S&P 500 rebased to that day's close.
Daily candles, adjusted for splits and dividends. Green arrows are insider buys, red are sells, sized by value; the dashed line is the close on the filing day, the dotted line SPY rebased to it.Charts by TradingView Lightweight Charts™
Rows in this filing
Every transaction in Form 4 0001193125-26-412431, as filed. Open on EDGAR
| Date | Transaction | Shares | Price | Value | Holdings after | Filed |
|---|---|---|---|---|---|---|
| Sep 30, 2026 | MOption exercise Ordinary Sharesindirect: See footnotes10b5-1 | +50,246 | - | - | 119,548 | 10 d ago |
| Sep 30, 2026 | SOpen-market sale Ordinary Sharesindirect: See footnotes10b5-1 | -50,246 | $25.03 | $1.3M | 69,302 | 10 d ago |
| Sep 30, 2026 | MOption exercise Option (right to buy)derivativeindirect: See footnote10b5-1 | -50,246 | $0.00 | $0 | 344,983 | 10 d ago |
Related signals
Other insiders at NewAmsterdam Pharma Co N.V. and this insider’s other filings.
| Score | Company | Insider | Value | Holdings | Filed |
|---|---|---|---|---|---|
| 38Weak | NAMSbuy NewAmsterdam Pharma Co N.V. | Michael H. Davidson Chief Executive Officer | $227k 10,000 shares | +1% | |
| 26Weak | NAMSsell NewAmsterdam Pharma Co N.V. | John W Smither director | $41k 1,600 shares | -15% | |
| 31Weak | NAMSbuy NewAmsterdam Pharma Co N.V. | James N Topper director | $69k 3,780 shares | +0% | |
| 30Weak | NewAmsterdam Pharma Co N.V. | Douglas F Kling Chief Operating Officer | $1.9M 100,000 shares | -69% | |
| 25Weak | NAMSbuy NewAmsterdam Pharma Co N.V. | James N Topper director | $167k 8,584 shares | +0% | |
| 45Moderate | NAMSsell NewAmsterdam Pharma Co N.V. | Louise Frederika Kooij Chief Accounting Officer | $3.1M 150,000 shares | -91% | |
| 14Weak | NewAmsterdam Pharma Co N.V. | ForGrowth NAP B.V. owner | $762k 29,846 shares | -0% | |
| 17Weak | NewAmsterdam Pharma Co N.V. | ForGrowth NAP B.V. owner | $1.9M 74,910 shares | -1% | |
| 17Weak | NewAmsterdam Pharma Co N.V. | ForGrowth NAP B.V. owner | $2.3M 91,068 shares | -1% | |
| 17Weak | NewAmsterdam Pharma Co N.V. | ForGrowth NAP B.V. owner | $4.1M 157,234 shares | -1% |
Not investment advice. Scores and forward returns are decision support built from public SEC filings and past prices; they describe what happened after comparable filings, not what will happen after this one. Do your own research and size your risk.