Company · Ownership research

NewAmsterdam Pharma Co N.V. NAMS

CIK 0001936258

Form 4 transactions dated Oct 1, 2023 to Oct 15, 2026, as reported to the SEC.

Insider trading Initial holdings Institutional holders

This page lists 30 of 63 rows; the complete set is available through the API.

Insider filings on file run through Oct 2, 2026.

Insider purchases & sales

Purchased: $1.09M
Sold: —

Oct 1, 2023 – Oct 2, 2026
Available records · partial months are marked ·

202610 of 27 preview events

Date	Insider	Activity	Trade value (USD)	% of prior holding
Sep 30, 2026	Kastelein Johannes Jacob Pieter Chief Scientific Officer · Director	Sale	$1.26M 50,246 shares sold	42.03% sold Indirect holding	▾
Sep 14, 2026	Davidson Michael H. Chief Executive Officer · Director	Purchase	$226.50K 10,000 shares bought	1.28% added Direct holding	▾
Sep 4, 2026	Smither John W Director	Sale	$40.51K 1,600 shares sold	15.44% sold Direct holding	▾
Aug 24, 2026	Kastelein Johannes Jacob Pieter Chief Scientific Officer · Director	Sale	$3.36M 125,000 shares sold	64.33% sold Indirect holding	▾
Jul 20, 2026	Kooij Louise Frederika Chief Accounting Officer	Sale	$3.19M 105,000 shares sold	81.17% sold Direct holding	▾
Jun 22, 2026	Kooij Louise Frederika Chief Accounting Officer	Sale	$1.21M 40,000 shares sold	62.16% sold Direct holding	▾
May 26, 2026	Kooij Louise Frederika Chief Accounting Officer	Sale	$2.32M 65,000 shares sold	72.75% sold Direct holding	▾
Mar 11, 2026	LANGE LOUIS G Director	Sale	$1.36M 44,619 shares sold	81.16% sold Direct holding	▾
Mar 9, 2026	Kastelein Johannes Jacob Pieter Chief Scientific Officer · Director	Sale	$3.07M 101,409 shares sold	59.40% sold Indirect holding	▾
Mar 6, 2026	LANGE LOUIS G Director	Sale	$828.95K 28,186 shares sold	100.00% sold Indirect holding	▾

Showing 27 / 27 record groups in 2026. The complete set is available through the API.

NewAmsterdam Pharma Co N.V. · NAMS

Follow the people behind the trades.

Log in to look up the full history beyond 3 years, use advanced screening & filtering, download CSV, and reach other datasets through the Akkru API.

Download CSV
Earlier filings
Advanced screening & filtering
API & AI access

Already have an account?

＋ New accounts get free API credits to explore data beyond ownership filings.

For AI agents & developers

The initial HTML of this page carries its exact data as script#research-data (JSON): values, units, scope, preview limits and SEC sources. Read it directly, no script or API key needed; script#research-access says what needs an account. For the year shown, this page lists 27 of 27 purchase / sale groups and 30 of 63 other groups; the totals and the monthly series cover the whole window.

Without an account: the last 3 years, with the row caps stated on the page. A free account opens all history on file on these pages and the CSV of what a page shows. Rows beyond the caps and bulk retrieval go through the authenticated API / MCP.

MCP  https://api.akkrudata.ai/mcp

list_insider_transactions
{"ticker":"NAMS","transaction_code":["P","S"],"transaction_form_type":"4","page_size":20}

Connect to MCP with OAuth and follow the returned pagination. Credits and usage limits depend on the account.

MCP endpoint: https://api.akkrudata.ai/mcp
API / MCP documentation: /documents
llms.txt: /llms.txt

Sources, coverage & how to read this data

Figures are as reported to the SEC and merged with later amendments where Akkru could match them. Preview limits apply to what is listed, not to the totals, which come from the complete reported data. Nothing is zero-filled: a missing quarter or month is shown as missing.

Non-cancelled, non-derivative purchase (P) and sale (S) rows dated inside the public window, as reported. Share totals are on today's split-adjusted basis. Includes open-market and private transactions. Data after the latest filing is not asserted complete and is not zero-filled. A grouped event shares filing, transaction date, security, code, direction, ownership bucket and source. Derivative groups also match underlying security, exercise price, exercise/expiration dates and footnote references. Reported rows are retained; P/S price lots can be grouped. Post-transaction balances are never summed.