Johannes Jacob Pieter Kastelein sold $1.6M of NAMS
Chief Scientific Officer at NewAmsterdam Pharma Co N.V.. 45,481 shares at an average of $35.31, traded Feb 20, 2026, filed Feb 24, 2026.
Score components
- +15RoleOfficer
- +25Trade size$1.6M at market
- +10Share of holdings soldSold 46% of holdings
- +15Cluster3 insiders selling within 14 days
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.
This signal so far: 1m -13.2%, 3m +0.3%, 6m -24.1%.
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 0001193125-26-067260, as filed. Open on EDGAR
| Date | Transaction | Shares | Price | Value | Holdings after | Filed |
|---|---|---|---|---|---|---|
| Feb 20, 2026 | SOpen-market sale Ordinary Shares | -14,692 | $35.00 | $514k | 84,289 | Feb 24, 2026 |
| Feb 20, 2026 | SOpen-market sale Ordinary Shares | -30,789 | $35.46 | $1.1M | 53,500 | Feb 24, 2026 |
Related signals
Other insiders at NewAmsterdam Pharma Co N.V. and this insider’s other filings.
| Score | Company | Insider | Value | Holdings | Filed |
|---|---|---|---|---|---|
| 15Weak | NewAmsterdam Pharma Co N.V. | Johannes Jacob Pieter Kastelein Chief Scientific Officer | $1.3M 50,246 shares | -42% | |
| 38Weak | NAMSbuy NewAmsterdam Pharma Co N.V. | Michael H. Davidson Chief Executive Officer | $227k 10,000 shares | +1% | |
| 34Weak | NewAmsterdam Pharma Co N.V. | John W Smither director | $41k 1,600 shares | -15% | |
| 33Weak | NewAmsterdam Pharma Co N.V. | Johannes Jacob Pieter Kastelein Chief Scientific Officer | $3.4M 125,000 shares | -64% | |
| 25Weak | NewAmsterdam Pharma Co N.V. | Louise Frederika Kooij Chief Accounting Officer | $3.2M 105,000 shares | -81% | |
| 25Weak | NewAmsterdam Pharma Co N.V. | Louise Frederika Kooij Chief Accounting Officer | $1.2M 40,000 shares | -62% | |
| 25Weak | NewAmsterdam Pharma Co N.V. | Louise Frederika Kooij Chief Accounting Officer | $2.3M 65,000 shares | -73% | |
| 75Notable | NewAmsterdam Pharma Co N.V. | Louis G Lange director | $1.4M 44,619 shares | -81% | |
| 73Notable | NewAmsterdam Pharma Co N.V. | Louis G Lange director | $829k 28,186 shares | -100% | |
| 40Moderate | NewAmsterdam Pharma Co N.V. | Johannes Jacob Pieter Kastelein Chief Scientific Officer | $9.1M 300,000 shares | -173% |
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.