NAMS insider transaction filings
NewAmsterdam Pharma Co N.V. — 50 most recent Form 4 filings from SEC EDGAR, normalized by FilingPulse. Latest filing: 2026-09-15. Screen NAMS transaction legs live →
Insider transaction summary — last 90 days
2026-06-24 to 2026-09-22, from the filings listed below: 6 Form 4 filings. Counts and totals are arithmetic on values as filed — descriptive data, not a recommendation.
- Open-market purchases (code P, non-derivative): 1 leg across 1 filing by 1 insider — 10,000 shares, $226,500 total (shares × price as filed).
- Open-market sales (code S, non-derivative): 7 legs across 4 filings by 3 insiders — 271,600 shares, $7,798,077 total (shares × price as filed).
- Other reported legs (grants, option exercises, tax withholding, gifts, derivative-security transactions, …): 12.
- Largest priced transaction: sale of 125,000 shares @ $26.91 ($3,363,750) by Kastelein Johannes Jacob Pieter, filed 2026-08-25.
By insider — same window
Open-market purchase/sale legs on non-derivative securities, grouped by the filing's reporting owner(s); joint filings appear once. Dollar totals cover priced legs only (shares × price as filed). Ordered by priced transaction value, largest first.
| Insider | Filings | Purchases (P) | Sales (S) | Other legs |
|---|---|---|---|---|
| Kooij Louise Frederika — Chief Accounting Officer | 2 | — | 5 legs · 145,000 sh · $4,393,815 | 8 |
| Kastelein Johannes Jacob Pieter — Chief Scientific Officer, Director | 1 | — | 1 leg · 125,000 sh · $3,363,750 | 2 |
| Davidson Michael H. — Chief Executive Officer, Director | 1 | 1 leg · 10,000 sh · $226,500 | — | — |
| Smither John W — Director | 1 | — | 1 leg · 1,600 sh · $40,512 | — |
| Gunning Robert William — Vice President, Controller | 1 | — | — | 2 |
Recent Form 4 filings — NewAmsterdam Pharma Co N.V.
| Filed | Form | Insider | Reported transactions | Source |
|---|---|---|---|---|
| 2026-09-15 | 4 | Davidson Michael H. — Chief Executive Officer, Director | Purchase (P): 10,000 @ $22.65 | EDGAR |
| 2026-09-09 | 4 | Smither John W — Director | Sale (S): 1,600 @ $25.32 | EDGAR |
| 2026-09-03 | 4 | Gunning Robert William — Vice President, Controller | Grant/award (A): 3,200 @ $0 · Grant/award (A): 14,000 (derivative) @ $0 | EDGAR |
| 2026-08-25 | 4 | Kastelein Johannes Jacob Pieter — Chief Scientific Officer, Director | Option exercise (M): 125,000 · Sale (S): 125,000 @ $26.91 · Option exercise (M): 125,000 (derivative) @ $0 | EDGAR |
| 2026-07-22 | 4 | Kooij Louise Frederika — Chief Accounting Officer | Option exercise (M): 25,000 @ $11.90 · Option exercise (M): 80,000 @ $11.17 · Sale (S): 70,200 @ $29.96 · Sale (S): 31,885 @ $31.05 · Sale (S): 2,915 @ $31.71 · Option exercise (M): 25,000 (derivative) @ $0 · +1 more | EDGAR |
| 2026-06-24 | 4 | Kooij Louise Frederika — Chief Accounting Officer | Option exercise (M): 25,000 @ $10.90 · Option exercise (M): 15,000 @ $11.90 · Sale (S): 39,700 @ $30.20 · Sale (S): 300 @ $30.73 · Option exercise (M): 25,000 (derivative) @ $0 · Option exercise (M): 15,000 (derivative) @ $0 | EDGAR |
| 2026-05-27 | 4 | Kooij Louise Frederika — Chief Accounting Officer | Option exercise (M): 60,000 @ $10 · Option exercise (M): 5,000 @ $10.90 · Sale (S): 65,000 @ $35.69 · Option exercise (M): 60,000 (derivative) @ $0 · Option exercise (M): 5,000 (derivative) @ $0 | EDGAR |
| 2026-03-12 | 4 | LANGE LOUIS G — Director | Sale (S): 44,173 @ $30.41 · Sale (S): 446 @ $31.23 | EDGAR |
| 2026-03-10 | 4 | LANGE LOUIS G — Director | Sale (S): 28,186 @ $29.41 · Option exercise/expiry (X): 44,619 @ $11.50 · Option exercise/expiry (X): 44,619 (derivative) @ $0 | EDGAR |
| 2026-03-09 | 4 | Kastelein Johannes Jacob Pieter — Chief Scientific Officer, Director | Option exercise (M): 104,467 · Sale (S): 104,467 @ $30.30 · Option exercise (M): 94,124 · Sale (S): 94,124 @ $30.32 · Option exercise (M): 101,409 · Sale (S): 101,409 @ $30.29 · +3 more | EDGAR |
| 2026-03-02 | 4 | Davidson Michael H. — Chief Executive Officer, Director | Option exercise (M): 443,707 · Sale (S): 443,707 @ $33.25 · Option exercise (M): 443,707 (derivative) @ $0 | EDGAR |
| 2026-02-26 | 4 | Davidson Michael H. — Chief Executive Officer, Director | Option exercise (M): 64,708 · Sale (S): 61,547 @ $36.13 · Sale (S): 3,161 @ $36.46 · Option exercise (M): 58,253 · Sale (S): 46,517 @ $35.11 · Sale (S): 10,436 @ $35.96 · +7 more | EDGAR |
| 2026-02-24 | 4 | Kastelein Johannes Jacob Pieter — Chief Scientific Officer, Director | Sale (S): 14,692 @ $35 · Sale (S): 30,789 @ $35.46 | EDGAR |
| 2026-01-29 | 4 | Kooij Louise Frederika — Chief Accounting Officer | Option exercise (M): 39,816 @ $10.90 · Sale (S): 39,816 @ $32.62 · Option exercise (M): 32,612 @ $10.90 · Sale (S): 32,612 @ $31.80 · Option exercise (M): 39,816 (derivative) @ $0 · Option exercise (M): 32,612 (derivative) @ $0 | EDGAR |
| 2026-01-27 | 4 | Kooij Louise Frederika — Chief Accounting Officer | Option exercise (M): 38,172 @ $10.90 · Sale (S): 25,405 @ $33.44 · Sale (S): 12,767 @ $34.37 · Option exercise (M): 34,400 @ $10.90 · Sale (S): 34,091 @ $32.77 · Sale (S): 309 @ $33.45 · +2 more | EDGAR |
| 2026-01-22 | 4 | Somaiya Mayur Ian — Chief Financial Officer | Option exercise (M): 60,216 @ $9.26 · Sale (S): 900 @ $30.64 · Sale (S): 39,712 @ $31.78 · Sale (S): 19,604 @ $32.38 · Option exercise (M): 39,784 @ $9.26 · Sale (S): 15,422 @ $33.25 · +3 more | EDGAR |
| 2026-01-09 | 4 | van der Kamp Hilde Johanna — Director | Grant/award (A): 3,400 · Grant/award (A): 15,300 (derivative) @ $0 | EDGAR |
| 2026-01-09 | 4 | McKenna Mark C. — Director | Grant/award (A): 3,400 · Grant/award (A): 15,300 (derivative) @ $0 | EDGAR |
| 2026-01-09 | 4 | Gulfo Adele M. — Director | Grant/award (A): 3,400 · Grant/award (A): 15,300 (derivative) @ $0 | EDGAR |
| 2026-01-09 | 4 | Davidson Michael H. — Chief Executive Officer, Director | Sale (S): 11,582 · Grant/award (A): 81,000 · Grant/award (A): 364,000 (derivative) @ $0 | EDGAR |
| 2026-01-09 | 4 | Smither John W — Director | Grant/award (A): 3,400 · Grant/award (A): 15,300 (derivative) @ $0 | EDGAR |
| 2026-01-09 | 4 | Lewis William — Director | Grant/award (A): 3,400 · Grant/award (A): 15,300 (derivative) @ $0 | EDGAR |
| 2026-01-09 | 4 | LANGE LOUIS G — Director | Grant/award (A): 3,400 · Grant/award (A): 15,300 (derivative) @ $0 | EDGAR |
| 2026-01-07 | 4 | Kastelein Johannes Jacob Pieter — Chief Scientific Officer, Director | Sale (S): 6,000 @ $33.25 · Grant/award (A): 25,500 · Grant/award (A): 115,000 (derivative) @ $0 | EDGAR |
| 2026-01-07 | 4 | Kooij Louise Frederika — Chief Accounting Officer | Sale (S): 2,647 @ $33.25 · Grant/award (A): 12,000 · Grant/award (A): 53,500 (derivative) @ $0 | EDGAR |
| 2026-01-07 | 4 | Somaiya Mayur Ian — Chief Financial Officer | Sale (S): 5,118 @ $33.25 · Grant/award (A): 25,500 · Grant/award (A): 115,000 (derivative) @ $0 | EDGAR |
| 2025-12-29 | 4 | Kooij Louise Frederika — Chief Accounting Officer | Option exercise (M): 75,117 @ $10 · Sale (S): 75,117 @ $36.21 · Option exercise (M): 26,011 @ $10 · Sale (S): 26,011 @ $35.68 · Option exercise (M): 38,872 @ $10 · Option exercise (M): 5,000 @ $10.90 · +5 more | EDGAR |
| 2025-09-17 | 4 | Topper James N — Director | Purchase (P): 660 @ $23.70 | EDGAR |
| 2025-09-10 | 4 | Kooij Louise Frederika — Chief Accounting Officer | Option exercise (M): 150,000 @ $10 · Sale (S): 53,104 @ $25.31 · Sale (S): 96,896 @ $26.11 · Option exercise (M): 150,000 (derivative) @ $0 | EDGAR |
| 2025-09-10 | 4 | Topper James N — Director | Purchase (P): 1,260 @ $24.99 | EDGAR |
| 2025-09-05 | 4 | Kooij Louise Frederika — Chief Accounting Officer | Sale (S): 18,073 @ $25.09 | EDGAR |
| 2025-09-04 | 4 | Kooij Louise Frederika — Chief Accounting Officer | Option exercise (M): 18,073 · Option exercise (M): 18,073 (derivative) @ $0 | EDGAR |
| 2025-08-27 | 4 | Kooij Louise Frederika — Chief Accounting Officer | Sale (S): 8,269 @ $24.86 | EDGAR |
| 2025-08-25 | 4 | Kastelein Johannes Jacob Pieter — Chief Scientific Officer, Director | Sale (S): 50,000 @ $24.29 · Sale (S): 42,342 @ $25.08 · Sale (S): 7,658 @ $25.49 | EDGAR |
| 2025-08-13 | 4 | Topper James N — Director | Purchase (P): 471 @ $23.98 | EDGAR |
| 2025-07-17 | 4 | Kling Douglas F — Chief Operating Officer | Option exercise (M): 47,569 @ $10.90 · Sale (S): 44,025 @ $21.38 · Sale (S): 3,544 @ $22.12 · Option exercise (M): 51,043 @ $10.90 · Sale (S): 51,043 @ $21.10 · Option exercise (M): 47,569 (derivative) @ $0 · +1 more | EDGAR |
| 2025-06-26 | 4 | Topper James N — Director | Purchase (P): 2,520 @ $18.43 · Purchase (P): 1,260 @ $18.26 | EDGAR |
| 2025-06-18 | 4 | Kling Douglas F — Chief Operating Officer | Option exercise (M): 78,101 @ $10 · Option exercise (M): 21,899 @ $10.90 · Sale (S): 81,891 @ $19.19 · Sale (S): 18,109 @ $19.75 · Option exercise (M): 78,101 (derivative) @ $0 · Option exercise (M): 21,899 (derivative) @ $0 | EDGAR |
| 2025-06-18 | 4 | Topper James N — Director | Purchase (P): 8,584 @ $19.50 | EDGAR |
| 2025-06-03 | 4 | Marino Michael F III — See Remarks | Grant/award (A): 55,000 · Grant/award (A): 315,000 (derivative) @ $0 | EDGAR |
| 2025-06-03 | 4 | LANGE LOUIS G — Director | Option exercise (M): 68 @ $0 · Option exercise (M): 68 (derivative) | EDGAR |
| 2025-05-19 | 4 | Kling Douglas F — Chief Operating Officer | Option exercise (M): 100,000 @ $10 · Sale (S): 100,000 · Option exercise (M): 100,000 (derivative) @ $0 | EDGAR |
| 2025-05-02 | 4 | Audet Juliette Berangere — See Remarks | Grant/award (A): 30,000 (derivative) @ $0 | EDGAR |
| 2025-05-02 | 4 | LANGE LOUIS G — Director | Option exercise (M): 69 @ $0 · Option exercise (M): 69 (derivative) | EDGAR |
| 2025-04-21 | 4 | LANGE LOUIS G — Director | Option exercise (M): 69 @ $0 · Option exercise (M): 69 (derivative) | EDGAR |
| 2025-04-17 | 4 | Kling Douglas F — Chief Operating Officer | Option exercise (M): 100,000 @ $10 · Sale (S): 99,090 · Sale (S): 910 · Option exercise (M): 100,000 (derivative) @ $0 | EDGAR |
| 2025-04-17 | 4 | Gulfo Adele M. — Director | Grant/award (A): 10,860 · Grant/award (A): 50,700 (derivative) @ $0 | EDGAR |
| 2025-03-28 | 4 | Davidson Michael H. — Chief Executive Officer, Director | Grant/award (A): 30,992 @ $0 · Option exercise (M): 38,394 @ $0 · Sale (S): 12,258 · Grant/award (A): 38,394 (derivative) · Option exercise (M): 38,394 (derivative) | EDGAR |
| 2025-03-28 | 4 | Topper James N — Director | Purchase (P): 1,135 @ $22.49 | EDGAR |
| 2025-03-28 | 4 | LANGE LOUIS G — Director | Option exercise (M): 3,102 @ $0 · Grant/award (A): 3,308 (derivative) · Option exercise (M): 3,102 (derivative) | EDGAR |
Recent 8-K events — NewAmsterdam Pharma Co N.V.
| Filed | Form | Items reported | Source |
|---|---|---|---|
| 2026-09-21 | 8-K | 8.01 — Other Events | EDGAR |
| 2026-08-14 | 8-K | 5.02 — Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers | EDGAR |
| 2026-08-14 | 8-K/A | 5.02 — Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers | EDGAR |
| 2026-08-05 | 8-K | 2.02 — Results of Operations and Financial Condition 9.01 — Financial Statements and Exhibits | EDGAR |
| 2026-07-24 | 8-K | 8.01 — Other Events 9.01 — Financial Statements and Exhibits | EDGAR |
| 2026-07-22 | 8-K | 5.02 — Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers | EDGAR |
| 2026-06-03 | 8-K | 5.02 — Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers 5.07 — Submission of Matters to a Vote of Security Holders 9.01 — Financial Statements and Exhibits | EDGAR |
| 2026-05-07 | 8-K | 2.02 — Results of Operations and Financial Condition 9.01 — Financial Statements and Exhibits | EDGAR |
| 2026-04-24 | 8-K | 5.02 — Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers | EDGAR |
| 2026-03-02 | 8-K | 7.01 — Regulation FD Disclosure 9.01 — Financial Statements and Exhibits | EDGAR |
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