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NewAmsterdam Pharma Co. N.V. planned insider sales

In the last twelve months insiders at NewAmsterdam Pharma Co. N.V. filed 18 Form 144 notices of planned sales, 7.6 million shares worth $278.8 million at the time of filing, from 12 sellers. The latest, filed 24 August 2026: Kastelein Johannes Jacob Pieter (affiliate), 125,000 shares worth $3.5 million, planned for around 24 August 2026 through J.P. Morgan Securities LLC.

FiledSellerRelationshipSharesValuePlanned saleSold, per Form 4BrokerHow acquiredFiling
24 August 2026Kastelein Johannes Jacob PieterAffiliate125,000$3.5 million24 August 2026175,246 shares from 24 August 2026J.P. Morgan Securities LLCOption ExerciseForm 144
26 May 2026Louise KooijOfficer210,000$7.4 million26 May 2026210,000 shares from 26 May 2026J.P. Morgan Securities LLCStock Option ExerciseForm 144
11 March 2026Louis G. LangeAffiliate44,619$1.4 million11 March 202644,619 shares from 11 March 2026J.P. Morgan Securities LLCWarrant ExerciseForm 144
6 March 2026Louis G. LangeAffiliate28,186$878,8396 March 202628,186 shares from 6 March 2026J.P. Morgan Securities LLCPurchase; RSU Award; Stock Option ExerciseForm 144
5 March 2026Kastelein Johannes Jacob PieterAffiliate300,000$9.4 million2 March 2026300,000 shares from 5 March 2026J.P. Morgan Securities LLCOption ExerciseForm 144
2 March 2026Michael H. DavidsonAffiliate443,707$15.7 million2 March 2026443,707 shares from 2 March 2026J.P. Morgan Securities LLCOption ExerciseForm 144
24 February 2026Michael H. DavidsonAffiliate750,000$27.1 million24 February 2026306,293 shares from 24 February 2026J.P. Morgan Securities LLCOption ExerciseForm 144
20 February 2026Kastelein Johannes Jacob PieterOfficer, Director45,481$1.6 million20 February 202645,481 shares from 20 February 2026ABN AMROVesting of RSU GrantForm 144
20 January 2026Mayur SomaiyaAffiliate200,000$6.3 million20 January 2026100,000 shares from 20 January 2026J.P. Morgan Securities LLCStock Option ExerciseForm 144
7 January 2026Michael Davidsonaffiliate11,582$410,8897 January 202611,582 shares from 7 January 2026J.P. Morgan Securities LLCVesting of RSU GrantForm 144
6 January 2026Douglas F KlingAffiliate300,000$10.0 million6 January 2026No matching Form 4 saleJ.P. Morgan Securities LLCStock Option ExerciseForm 144
5 January 2026Louise Kooijaffiliate2,647$88,0125 January 2026147,647 shares from 5 January 2026J.P. Morgan Securities LLCVesting of RSU GrantForm 144
5 January 2026Mayur Ian Somaiyaaffiliate5,118$170,1735 January 20265,118 shares from 5 January 2026J.P. Morgan Securities LLCVesting of RSU GrantForm 144
5 January 2026Johannes KasteleinAffiliate6,000$199,4995 January 20266,000 shares from 5 January 2026J.P. Morgan Securities LLCVesting of RSU GrantForm 144
23 December 2025Louise KooijOfficer290,000$10.6 million23 December 2025145,000 shares from 23 December 2025J.P. Morgan Securities LLCStock Option ExerciseForm 144
2 December 2025BCIP Life Sciences Associates, LPFormer Affiliate32,571$1.2 million2 December 2025No matching Form 4 saleGoldman Sachs & Co. LLCPurchase of ordinary shares in the initial public offering of Frazier Lifesciences Acquisition Corporation, which ordinary shares were automatically exchanged on a 1:1 basis for ordinary shares of the Issuer on November 22, 2022.Form 144
2 December 2025Bain Capital Life Sciences Fund II, L.P.Former Affiliate267,429$10.3 million2 December 2025No matching Form 4 saleGoldman Sachs & Co. LLCPurchase of ordinary shares in the initial public offering of Frazier Lifesciences Acquisition Corporation, which ordinary shares were automatically exchanged on a 1:1 basis for ordinary shares of the Issuer on November 22, 2022.Form 144
2 December 2025BCLS II Investco, LPFormer Affiliate4,500,000$172.5 million2 December 2025No matching Form 4 saleGoldman Sachs & Co. LLCPurchase of ordinary shares directly from the Issuer in a private placement.; Purchase of ordinary shares in an underwritten public offering.Form 144
A Form 144 is the notice an insider files with the SEC before selling restricted or control shares over the Rule 144 thresholds; it says what may be sold, not what was.
Read moreValue is the filer's own aggregate market value. Sold, per Form 4: the same seller's open-market sales on Form 4 from the notice's date to 90 days after, added up, as they appear on the insiders page; a holder who files no Form 4, such as some large holders, never shows one. What is a Form 144?