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sellWeak10b5-1 plan

Louise Frederika Kooij sold $2.3M of NAMS

Chief Accounting Officer at NewAmsterdam Pharma Co N.V.. 65,000 shares at an average of $35.69, traded May 26, 2026, filed May 27, 2026.

Warning score
25
Value
$2.3M
65,000 shares
Holdings after
24,353
-73% from before
From 52-week low
+112%
low $17.01, close $36.11
From 52-week high
-13%
high $41.45, as of May 26, 2026

Score components

  • Role
    Officer
    +15
  • Trade size
    $2.3M at market
    +25
  • Share of holdings sold
    Sold 73% of holdings
    +20
  • Cluster
    No other insider selling within 14 days
    0
  • Exercise and sell
    Shares came from an option exercise in the same filing
    -15
  • 10b5-1 plan
    Pre-scheduled under a 10b5-1 plan
    -20

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.

NAMSOct 12, 2026 · close 21.25
Since filing May 27, 2026: -41.9%SPY +4.2% · excess -46.1%

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 0001193125-26-241983, as filed. Open on EDGAR

DateTransactionSharesPriceValueHoldings afterFiled
May 26, 2026MOption exercise
Ordinary Shares10b5-1
+60,000$10.00$600k84,353May 27, 2026
May 26, 2026MOption exercise
Ordinary Shares10b5-1
+5,000$10.90$55k89,353May 27, 2026
May 26, 2026SOpen-market sale
Ordinary Shares10b5-1
-65,000$35.69$2.3M24,353May 27, 2026
May 26, 2026MOption exercise
Option (right to buy)derivative10b5-1
-60,000$0.00$080,015May 27, 2026
May 26, 2026MOption exercise
Option (right to buy)derivative10b5-1
-5,000$0.00$068,134May 27, 2026

Related signals

Other insiders at NewAmsterdam Pharma Co N.V. and this insider’s other filings.

ScoreCompanyInsiderValueHoldingsFiled
15Weak
NAMSsell10b5-1
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%
34Weak
NAMSsell 2
NewAmsterdam Pharma Co N.V.
John W Smither
director
$41k
1,600 shares
-15%
33Weak
NAMSsell 210b5-1
NewAmsterdam Pharma Co N.V.
Johannes Jacob Pieter Kastelein
Chief Scientific Officer
$3.4M
125,000 shares
-64%
25Weak
NAMSsell10b5-1
NewAmsterdam Pharma Co N.V.
Louise Frederika Kooij
Chief Accounting Officer
$3.2M
105,000 shares
-81%
25Weak
NAMSsell10b5-1
NewAmsterdam Pharma Co N.V.
Louise Frederika Kooij
Chief Accounting Officer
$1.2M
40,000 shares
-62%
75Notable
NAMSsell 3
NewAmsterdam Pharma Co N.V.
Louis G Lange
director
$1.4M
44,619 shares
-81%
73Notable
NAMSsell 3
NewAmsterdam Pharma Co N.V.
Louis G Lange
director
$829k
28,186 shares
-100%
40Moderate
NAMSsell 310b5-1
NewAmsterdam Pharma Co N.V.
Johannes Jacob Pieter Kastelein
Chief Scientific Officer
$9.1M
300,000 shares
-173%
70Notable
NAMSsell 3
NewAmsterdam Pharma Co N.V.
Michael H. Davidson
Chief Executive Officer
$15M
443,707 shares
-72%

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.

Louise Frederika Kooij sold $2.3M of NAMS | InsiderTell