Johannes Jacob Pieter Kastelein sold $2.5M of NAMS
Chief Scientific Officer at NewAmsterdam Pharma Co N.V.. 100,000 shares at an average of $24.72, traded Aug 21, 2025, filed Aug 25, 2025.
Score components
- +15RoleOfficer
- +25Trade size$2.5M at market
- +20Share of holdings soldSold 59% of holdings
- +8Cluster2 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.
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 0000950170-25-111241, as filed. Open on EDGAR
| Date | Transaction | Shares | Price | Value | Holdings after | Filed |
|---|---|---|---|---|---|---|
| Aug 21, 2025 | SOpen-market sale Ordinary Sharesindirect: See footnote | -50,000 | $24.29 | $1.2M | 119,302 | Aug 25, 2025 |
| Aug 22, 2025 | SOpen-market sale Ordinary Sharesindirect: See footnote | -42,342 | $25.08 | $1.1M | 76,960 | Aug 25, 2025 |
| Aug 22, 2025 | SOpen-market sale Ordinary Sharesindirect: See footnote | -7,658 | $25.49 | $195k | 69,302 | Aug 25, 2025 |
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% | |
| 26Weak | NAMSsell NewAmsterdam Pharma Co N.V. | John W Smither director | $41k 1,600 shares | -15% | |
| 55Moderate | NAMSsell NewAmsterdam Pharma Co N.V. | Michael H. Davidson Chief Executive Officer | $15M 443,707 shares | -72% | |
| 35Weak | NewAmsterdam Pharma Co N.V. | Michael H. Davidson Chief Executive Officer | $11M 306,293 shares | -58% | |
| 25Weak | NewAmsterdam Pharma Co N.V. | Louise Frederika Kooij Chief Accounting Officer | $5.2M 145,000 shares | -161% | |
| 15Weak | NAMSbuy NewAmsterdam Pharma Co N.V. | James N Topper director | $16k 660 shares | +0% | |
| 45Moderate | NAMSsell NewAmsterdam Pharma Co N.V. | Louise Frederika Kooij Chief Accounting Officer | $3.9M 150,000 shares | -91% | |
| 20Weak | NAMSbuy NewAmsterdam Pharma Co N.V. | James N Topper director | $31k 1,260 shares | +0% | |
| 60Notable | NewAmsterdam Pharma Co N.V. | Louise Frederika Kooij Chief Accounting Officer | $453k 18,073 shares | -55% |
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.