$NAMS insider trading
Over the last 12 months, NewAmsterdam Pharma insiders reported 2 buys totaling $47K and 19 sales totaling $65.8M across SEC Form 4 filings. 67% of those filings were made under pre-arranged 10b5-1 trading plans.
- Bought · 12m
- $47K 2 events
- Sold · 12m
- $65.8M 19 events
- Events · 12m
- 21 Form 4 filings, grouped
- Insiders · 12m
- 6 distinct reporters
- 10b5-1 share
- 67% of events, not dollars
All insider trades
Scroll the table sideways for price, value and marks.
| Date | Insider | Type | Shares | Avg price | Value | Δ stake | Marks |
|---|---|---|---|---|---|---|---|
| Aug 24, 2026 | Kastelein Johannes Jacob PieterChief Scientific Officer · O·D | ▼ Sale | 125,000 | $26.91 | $3.4M | -64.3% | plan · indirect |
| Jul 20, 2026 | Kooij Louise FrederikaChief Accounting Officer · O | ▼ Sale | 105,000 | $30.34 | $3.2M | -81.2% | plan · 3 tranches |
| Jun 22, 2026 | Kooij Louise FrederikaChief Accounting Officer · O | ▼ Sale | 40,000 | $30.2 | $1.2M | -62.2% | plan · 2 tranches |
| May 26, 2026 | Kooij Louise FrederikaChief Accounting Officer · O | ▼ Sale | 65,000 | $35.69 | $2.3M | -72.7% | plan |
| Mar 11, 2026 | LANGE LOUIS GD | ▼ Sale | 44,619 | $30.42 | $1.4M | -81.2% | 2 tranches |
| Mar 9, 2026 | Kastelein Johannes Jacob PieterChief Scientific Officer · O·D | ▼ Sale | 300,000 | $30.3 | $9.1M | -81.2% | plan · 3 tranches · indirect |
| Mar 6, 2026 | LANGE LOUIS GD | ▼ Sale | 28,186 | $29.41 | $829K | -100% | indirect |
| Mar 2, 2026 | Davidson Michael H.Chief Executive Officer · O·D | ▼ Sale | 443,707 | $33.25 | $14.8M | -71.8% | — |
| Feb 26, 2026 | Davidson Michael H.Chief Executive Officer · O·D | ▼ Sale | 306,293 | $34.53 | $10.6M | -63.8% | plan · 7 tranches |
| Feb 20, 2026 | Kastelein Johannes Jacob PieterChief Scientific Officer · O·D | ▼ Sale | 45,481 | $35.31 | $1.6M | -45.9% | 2 tranches |
| Jan 28, 2026 | Kooij Louise FrederikaChief Accounting Officer · O | ▼ Sale | 72,428 | $32.25 | $2.3M | -74.8% | plan · 2 tranches |
| Jan 26, 2026 | Kooij Louise FrederikaChief Accounting Officer · O | ▼ Sale | 72,572 | $33.29 | $2.4M | -74.9% | plan · 4 tranches |
| Jan 21, 2026 | Somaiya Mayur IanChief Financial Officer · O | ▼ Sale | 100,000 | $32.61 | $3.3M | -63.1% | plan · 5 tranches |
| Jan 7, 2026 | Davidson Michael H.Chief Executive Officer · O·D | ▼ Sale | 11,582 | — | — | -3% | plan |
| Jan 5, 2026 | Kastelein Johannes Jacob PieterChief Scientific Officer · O·D | ▼ Sale | 6,000 | $33.25 | $200K | -7.5% | plan |
| Jan 5, 2026 | Kooij Louise FrederikaChief Accounting Officer · O | ▼ Sale | 2,647 | $33.25 | $88K | -17.6% | plan |
| Jan 5, 2026 | Somaiya Mayur IanChief Financial Officer · O | ▼ Sale | 5,118 | $33.25 | $170K | -13.5% | plan |
| Dec 26, 2025 | Kooij Louise FrederikaChief Accounting Officer · O | ▼ Sale | 145,000 | $35.84 | $5.2M | -90.6% | plan · 3 tranches |
| Sep 15, 2025 | Topper James ND | ▲ Buy | 660 | $23.7 | $16K | — | indirect |
| Sep 9, 2025 | Kooij Louise FrederikaChief Accounting Officer · O | ▼ Sale | 150,000 | $25.83 | $3.9M | -90.9% | 2 tranches |
| Sep 8, 2025 | Topper James ND | ▲ Buy | 1,260 | $24.99 | $31K | — | indirect |
| Sep 3, 2025 | Kooij Louise FrederikaChief Accounting Officer · O | ▼ Sale | 18,073 | $25.09 | $453K | -54.6% | — |
| Aug 25, 2025 | Kooij Louise FrederikaChief Accounting Officer · O | ▼ Sale | 8,269 | $24.86 | $206K | -35.5% | — |
| Aug 22, 2025 | Kastelein Johannes Jacob PieterChief Scientific Officer · O·D | ▼ Sale | 100,000 | $24.72 | $2.5M | -59.1% | 3 tranches · indirect |
| Aug 11, 2025 | Topper James ND | ▲ Buy | 471 | $23.98 | $11K | — | indirect |
Every $NAMS filing on this page is one API call away
The same Form 4 data over REST or MCP, already grouped into events with the plan flag and the dollar value read. A free key does 100 calls a day and needs no card. Prefer email? NewAmsterdam Pharma filings can reach your inbox instead.
Corporate insiders — officers, directors and 10%+ owners — must report their trades to the SEC on Form 4 within two business days. This page shows open-market activity: purchases (code P), sales (S) and dispositions back to the issuer (D). Scheduled compensation events such as stock grants and option exercises are also filed on Form 4 but carry no trading signal, so they are not shown and counts here can be lower than the raw EDGAR filing total. We group each filing's transactions into one economic event (a laddered 10b5-1 sale is one event, not 25 rows), flag pre-arranged plans and late filings, and link every event to its AI-scored article in the $NAMS feed.