NAMS insider buying and SEC filings, explained
NewAmsterdam Pharma Co N.V. · CIK 1936258
Tracked: Forms 3/4/5, 8-K, NT · All filings on sec.gov
Company profile
- Exchanges
- Nasdaq, Nasdaq
- Industry (SIC)
- Pharmaceutical Preparations
- State of incorporation
- P7
- Fiscal year end
- Dec 31
- Former names
- NewAmsterdam Pharma Co B.V.
Insider activity in the last 12 months
Bought
$227K
Insiders who bought
1
Sold (not marked 10b5-1)
$3.8M
Planned sales (10b5-1)
$44.7M
Insider purchases and sales, last 12 months
| Traded | Type | What was filed | Source |
|---|---|---|---|
| Sep 30, 2026 | Planned (10b5-1) | Johannes Jacob Pieter Kastelein (Chief Scientific Officer and Director) sold 50,246 shares indirectly at about $25.03 ($1.3M), marked as a 10b5-1 plan trade. Indirect holdings down 42% to 69,302 shares. | SEC filing Filed Oct 2, 2026, 4:30 PM ET |
| Sep 14, 2026 | Purchase (code P) | Michael H. Davidson (CEO and Director) bought 10,000 shares at $22.65 ($227K), reported as a purchase (code P). Holdings up 1% to 792,923 shares. Not marked as a 10b5-1 plan trade. | SEC filing Filed Sep 15, 2026 |
| Sep 4, 2026 | Sale | John W Smither (Director) sold 1,600 shares at about $25.32 ($41K). Holdings down 15% to 8,760 shares. Not marked as a 10b5-1 plan trade. | SEC filing Filed Sep 9, 2026 |
| Aug 24, 2026 | Planned (10b5-1) | Johannes Jacob Pieter Kastelein (Chief Scientific Officer and Director) sold 125,000 shares indirectly at about $26.91 ($3.4M), marked as a 10b5-1 plan trade. Indirect holdings down 64% to 69,302 shares. | SEC filing Filed Aug 25, 2026 |
| Jul 20, 2026 | Planned (10b5-1) | Louise Frederika Kooij (Chief Accounting Officer) sold 105,000 shares at about $30.34 ($3.2M), marked as a 10b5-1 plan trade. Holdings down 81% to 24,353 shares. | SEC filing Filed Jul 22, 2026 |
| Jun 22, 2026 | Planned (10b5-1) | Louise Frederika Kooij (Chief Accounting Officer) sold 40,000 shares at about $30.20 ($1.2M), marked as a 10b5-1 plan trade. Holdings down 62% to 24,353 shares. | SEC filing Filed Jun 24, 2026 |
| May 26, 2026 | Planned (10b5-1) | Louise Frederika Kooij (Chief Accounting Officer) sold 65,000 shares at about $35.69 ($2.3M), marked as a 10b5-1 plan trade. Holdings down 73% to 24,353 shares. | SEC filing Filed May 27, 2026 |
| Mar 11, 2026 | Sale | Louis G. Lange (Director) sold 44,619 shares at about $30.42 ($1.4M). Holdings down 81% to 10,360 shares. Not marked as a 10b5-1 plan trade. | SEC filing Filed Mar 12, 2026 |
| Mar 6, 2026 | Sale | Louis G. Lange (Director) sold 28,186 shares indirectly at about $29.41 ($829K). Indirect holdings down 100% to 0 shares. Not marked as a 10b5-1 plan trade. | SEC filing Filed Mar 10, 2026 |
| Mar 5–9, 2026 | Planned (10b5-1) | Johannes Jacob Pieter Kastelein (Chief Scientific Officer and Director) sold 300,000 shares indirectly between Mar 5 and Mar 9 at about $30.30 ($9.1M), marked as a 10b5-1 plan trade. Indirect holdings down 81% to 69,302 shares. | SEC filing Filed Mar 9, 2026 |
| Feb 24–26, 2026 | Planned (10b5-1) | Michael H. Davidson (CEO and Director) sold 306,293 shares between Feb 24 and Feb 26 at about $34.53 ($10.6M), marked as a 10b5-1 plan trade. Holdings down 64% to 174,144 shares. | SEC filing Filed Feb 26, 2026 |
| Feb 20, 2026 | Sale | Johannes Jacob Pieter Kastelein (Chief Scientific Officer and Director) sold 45,481 shares at about $35.31 ($1.6M). Holdings down 46% to 53,500 shares. Not marked as a 10b5-1 plan trade. | SEC filing Filed Feb 24, 2026 |
| Jan 27–28, 2026 | Planned (10b5-1) | Louise Frederika Kooij (Chief Accounting Officer) sold 72,428 shares between Jan 27 and Jan 28 at about $32.25 ($2.3M), marked as a 10b5-1 plan trade. Holdings down 75% to 24,353 shares. | SEC filing Filed Jan 29, 2026 |
| Jan 23–26, 2026 | Planned (10b5-1) | Louise Frederika Kooij (Chief Accounting Officer) sold 72,572 shares between Jan 23 and Jan 26 at about $33.29 ($2.4M), marked as a 10b5-1 plan trade. Holdings down 75% to 24,353 shares. | SEC filing Filed Jan 27, 2026 |
| Jan 20–21, 2026 | Planned (10b5-1) | Mayur Ian Somaiya (CFO) sold 100,000 shares between Jan 20 and Jan 21 at about $32.61 ($3.3M), marked as a 10b5-1 plan trade. Holdings down 63% to 58,382 shares. | SEC filing Filed Jan 22, 2026 |
| Jan 7, 2026 | Planned (10b5-1) | Michael H. Davidson (CEO and Director) sold 11,582 shares; the filing does not report a price. Holdings down 3% to 378,859 shares. | SEC filing Filed Jan 9, 2026 |
| Jan 5, 2026 | Planned (10b5-1) | Johannes Jacob Pieter Kastelein (Chief Scientific Officer and Director) sold 6,000 shares at about $33.25 ($200K), marked as a 10b5-1 plan trade. Holdings down 8% to 73,481 shares. | SEC filing Filed Jan 7, 2026 |
| Jan 5, 2026 | Planned (10b5-1) | Louise Frederika Kooij (Chief Accounting Officer) sold 2,647 shares at about $33.25 ($88K), marked as a 10b5-1 plan trade. Holdings down 18% to 12,353 shares. | SEC filing Filed Jan 7, 2026 |
| Jan 5, 2026 | Planned (10b5-1) | Mayur Ian Somaiya (CFO) sold 5,118 shares at about $33.25 ($170K), marked as a 10b5-1 plan trade. Holdings down 13% to 32,882 shares. | SEC filing Filed Jan 7, 2026 |
| Dec 23–26, 2025 | Planned (10b5-1) | Louise Frederika Kooij (Chief Accounting Officer) sold 145,000 shares between Dec 23, 2025 and Dec 26, 2025 at about $35.84 ($5.2M), marked as a 10b5-1 plan trade. Holdings down 91% to 15,000 shares. | SEC filing Filed Dec 29, 2025 |
25 routine transactions (such as grants, option exercises or tax withholding) are not listed.
Cluster buys
No cluster buys in the last 12 months.
Red flags
No red flags in the last 12 months.
Key events
No key events in the last 12 months.
8-K filings, last 12 months
No 8-K filings in the last 12 months.
Red flags are objective triggers only: the item or form filed, never an opinion.
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