KOOIJ LOUISE FREDERIKA (Chief Accounting Officer) sold 90.6% of their position (145K shares) of NEWAMSTERDAM PHARMA CO N.V. on the open market

Open‑market sale worth $5.20M — a major position exit. Review remaining holdings and any 10b5‑1 plan disclosures.

S · 3 sales

KOOIJ LOUISE FREDERIKA

Filed: 12/29/2025ACC: 0001193125-25-335513

InsiderKOOIJ LOUISE FREDERIKACIK 2004379

→

IssuerNEWAMSTERDAM PHARMA CO N.V.CIK 1936258

Officer· Chief Accounting Officer

Since Jan 2026

-145K

Net shares

Net seller

$5.20M

Total sold

Open market trades

0B · 3S

Total transactions

145K acquired · 290K disposed

Non-Derivative Transactions7

Ordinary Shares

Direct

M · Option Exercise

+75.12K

Price / share

$10.00

Trade value

$751.17K

% of position

500.8%

12/23/2025

15K→90.12K

Ordinary Shares

Direct

S · Sale

−75.12K

Price / share

$36.21

Trade value

$2.72M

% of position

83.4%

12/23/2025

90.12K→15K

Ordinary Shares

Direct

M · Option Exercise

+26.01K

Price / share

$10.00

Trade value

$260.11K

% of position

173.4%

12/24/2025

15K→41.01K

Ordinary Shares

Direct

S · Sale

−26.01K

Price / share

$35.68

Trade value

$928.07K

% of position

63.4%

12/24/2025

41.01K→15K

Ordinary Shares

Direct

M · Option Exercise

+38.87K

Price / share

$10.00

Trade value

$388.72K

% of position

259.1%

12/26/2025

15K→53.87K

Ordinary Shares

Direct

M · Option Exercise

+5K

Price / share

$10.90

Trade value

$54.50K

% of position

9.3%

12/26/2025

53.87K→58.87K

Ordinary Shares

Direct

S · Sale

−43.87K

Price / share

$35.30

Trade value

$1.55M

% of position

74.5%

12/26/2025

58.87K→15K

Total

Net shares

+0.00

Net value

-$3.74M

Security	Date	Type	Shares	Price / Share	Trade Value	% of Position	Held Before	Held After
Ordinary Shares Direct	12/23/2025	M · Option Exercise	+75.12K	$10.00	$751.17K	500.8%	15K	90.12K
Ordinary Shares Direct	12/23/2025	S · Sale	−75.12K	$36.21	$2.72M	83.4%	90.12K	15K
Ordinary Shares Direct	12/24/2025	M · Option Exercise	+26.01K	$10.00	$260.11K	173.4%	15K	41.01K
Ordinary Shares Direct	12/24/2025	S · Sale	−26.01K	$35.68	$928.07K	63.4%	41.01K	15K
Ordinary Shares Direct	12/26/2025	M · Option Exercise	+38.87K	$10.00	$388.72K	259.1%	15K	53.87K
Ordinary Shares Direct	12/26/2025	M · Option Exercise	+5K	$10.90	$54.50K	9.3%	53.87K	58.87K
Ordinary Shares Direct	12/26/2025	S · Sale	−43.87K	$35.30	$1.55M	74.5%	58.87K	15K
Total			+0.00		-$3.74M

Derivative Transactions4

Option (right to buy)

Direct

M · Option Exercise

Converts to

Ordinary Shares

75.12K shares

−75.12K

Strike price

10.00

Held after

204.90K

Exercisable

—

12/23/2025

Option (right to buy)

Direct

M · Option Exercise

Converts to

Ordinary Shares

26.01K shares

−26.01K

Strike price

10.00

Held after

178.89K

Exercisable

—

12/24/2025

Option (right to buy)

Direct

M · Option Exercise

Converts to

Ordinary Shares

38.87K shares

−38.87K

Strike price

10.00

Held after

140.01K

Exercisable

—

12/26/2025

Option (right to buy)

Direct

M · Option Exercise

Converts to

Ordinary Shares

5K shares

−5K

Strike price

10.90

Held after

218.13K

Exercisable

—

12/26/2025

Security	Converts To	Date	Type	Shares	Strike Price	Exercisable	Held After
Option (right to buy) Direct	Ordinary Shares75.12K shares	12/23/2025	M · Option Exercise	−75.12K	10.00	—	204.90K
Option (right to buy) Direct	Ordinary Shares26.01K shares	12/24/2025	M · Option Exercise	−26.01K	10.00	—	178.89K
Option (right to buy) Direct	Ordinary Shares38.87K shares	12/26/2025	M · Option Exercise	−38.87K	10.00	—	140.01K
Option (right to buy) Direct	Ordinary Shares5K shares	12/26/2025	M · Option Exercise	−5K	10.90	—	218.13K