CSO at NewAmsterdam Pharma (NAMS) exercises options and sells 300,000 shares

Rhea-AI Filing Summary

NewAmsterdam Pharma Co N.V. Chief Scientific Officer Johannes Jacob Pieter Kastelein, through Futurum B.V., exercised options for 300,000 Ordinary Shares at an exercise price of EUR 1.16392 and sold 300,000 shares in open-market transactions around $30 per share between March 5–9, 2026. The shares and options are held indirectly via Futurum and NAP PoolCo B.V. for his benefit, with the reporting person retaining sole voting and investment control.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

X

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Kastelein Johannes Jacob Pieter

(Last) (First) (Middle)

C/O NEWAMSTERDAM PHARMA COMPANY N.V.

GOOIMEER 2-35

(Street)

NAARDEN P7 1411 DC

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
NewAmsterdam Pharma Co N.V. [ NAMS ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Scientific Officer

3. Date of Earliest Transaction (Month/Day/Year)
03/05/2026

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Ordinary Shares	03/05/2026		M		104,467	A	(1)	173,769	I	See footnote(2)
Ordinary Shares	03/05/2026		S		104,467	D	$30.3(3)	69,302	I	See footnote(2)
Ordinary Shares	03/06/2026		M		94,124	A	(1)	163,426	I	See footnote(2)
Ordinary Shares	03/06/2026		S		94,124	D	$30.32(4)	69,302	I	See footnote(2)
Ordinary Shares	03/09/2026		M		101,409	A	(1)	170,711	I	See footnote(2)
Ordinary Shares	03/09/2026		S		101,409	D	$30.29(5)	69,302	I	See footnote(2)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Option (right to buy)	(1)	03/05/2026		M			104,467	(6)	07/06/2031	Ordinary Shares	104,467	$0	715,762	I	See footnote(7)
Option (right to buy)	(1)	03/06/2026		M			94,124	(6)	07/06/2031	Ordinary Shares	94,124	$0	621,638	I	See footnote(7)
Option (right to buy)	(1)	03/09/2026		M			101,409	(6)	07/06/2031	Ordinary Shares	101,409	$0	520,229	I	See footnote(7)

Explanation of Responses:

1. The exercise price of the option is EUR 1.16392.

2. The Ordinary Shares are held by Futurum B.V. ("Futurum") for the benefit of the Reporting Person. The Reporting Person exercises sole voting and investment control over the Ordinary Shares held by Futurum.

3. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $30.00 per share to $30.55 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold in each transaction.

4. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $30.00 per share to $30.42 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold in each transaction.

5. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $30.00 per share to $30.80 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold in each transaction.

6. The option was granted on November 22, 2022 to replace an option originally granted on July 6, 2021 which was cancelled in connection with the consummation of NewAmsterdam Pharma Company N.V.'s business combination with Frazier Lifesciences Acquisition Corporation. 292,214 of the shares underlying the option immediately vested on the grant date. 25% of the remaining shares underlying the option vested on January 1, 2021, the one-year anniversary of vesting start date, with the remaining shares vesting in equal monthly installments thereafter for three years, subject to the Reporting Person's continued service through each such date.

7. The option was granted to and is held by Futurum through NAP PoolCo B.V. ("PoolCo") for the benefit of the Reporting Person. The Reporting Person exercises sole voting and investment control over the securities held by Futurum through PoolCo. PoolCo has no voting or investment control or pecuniary interest in the securities held on behalf of Futurum. Upon exercise of the option, the Ordinary Shares were issued to Futurum directly, pursuant to a written agreement among Futurum, PoolCo and the Issuer.

	/s/ Louise Kooij by Power of Attorney for Johannes Jacob Pieter Kastelein	03/09/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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FAQ

What insider transactions did NewAmsterdam Pharma (NAMS) report for its Chief Scientific Officer?

NewAmsterdam Pharma reported that Chief Scientific Officer Johannes Jacob Pieter Kastelein exercised options for 300,000 Ordinary Shares and sold 300,000 shares in open-market transactions. The trades occurred between March 5 and March 9, 2026, and were reported as indirect holdings through Futurum B.V. and NAP PoolCo B.V.

How many NewAmsterdam Pharma (NAMS) shares were sold in this Form 4 filing and at what prices?

The Form 4 shows sales of 300,000 NewAmsterdam Pharma Ordinary Shares in three tranches of 104,467, 94,124 and 101,409 shares. Weighted average sale prices were approximately $30.30, $30.32 and $30.29 per share, with individual trades ranging roughly between $30.00 and $30.80 per share.

What option exercises did the NewAmsterdam Pharma (NAMS) Form 4 disclose for the CSO?

The filing discloses option exercises for a total of 300,000 shares, in blocks of 104,467, 94,124 and 101,409 shares. The option carried an exercise price of EUR 1.16392 per share and was originally granted in November 2022 as a replacement for an earlier canceled option.

How are the NewAmsterdam Pharma (NAMS) shares held that are reported in this Form 4?

The Ordinary Shares are held by Futurum B.V. for the benefit of the reporting person, and certain options were held through NAP PoolCo B.V. The filing states that the reporting person exercises sole voting and investment control over securities held by Futurum, while PoolCo has no voting or investment control or pecuniary interest.

Over what period did the NewAmsterdam Pharma (NAMS) insider transactions in this Form 4 occur?

The reported transactions occurred on three dates: March 5, March 6 and March 9, 2026. Each date shows an option exercise converting into Ordinary Shares followed by an open-market sale of an equal number of shares, all reported as indirect holdings associated with the Chief Scientific Officer.

What is notable about the pricing details in the NewAmsterdam Pharma (NAMS) Form 4 sales?

For each sale date, the Form 4 reports a single weighted average price, while footnotes clarify that shares were sold in multiple trades within price ranges around $30.00 to $30.80. The reporting person offers to provide full per-transaction details to the issuer, security holders or SEC staff upon request.