Insider moves at NewAmsterdam Pharma (NAMS): sale, RSUs, options

Rhea-AI Filing Summary

NewAmsterdam Pharma Co N.V. Chief Scientific Officer and director Johannes Jacob Pieter Kastelein reported several equity transactions. On January 5, 2026, he sold 6,000 ordinary shares at a weighted average price of $33.25 per share, in a pre-arranged sale made solely to cover tax withholding tied to vesting restricted stock units, described as non-discretionary.

On January 7, 2026, he acquired 25,500 restricted stock units (RSUs) for no consideration, each RSU representing one ordinary share and vesting in three equal annual installments, leaving him with 98,981 ordinary shares beneficially owned. He also received an option to buy 115,000 ordinary shares at an exercise price of $35.45 per share, expiring January 7, 2036, with 25% vesting on January 2, 2027 and the remainder vesting in equal monthly installments over three years, all subject to continued service.

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

OMB APPROVAL

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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)
01/05/2026

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	01/05/2026		S(1)		6,000	D	$33.25(2)	73,481	D
Ordinary Shares	01/07/2026		A		25,500(3)	A	(4)	98,981	D

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)	$35.45	01/07/2026		A		115,000		(5)	01/07/2036	Ordinary Shares	115,000	$0.00	115,000	D

Explanation of Responses:

1. Represents pre-arranged sale of shares by the Reporting Person solely to cover tax withholding obligations in connection with the vesting and settlement of restricted stock units (RSUs) pursuant to sell-to-cover agreement entered into with the Issuer. The sale does not represent a discretionary transaction by the Reporting Person.

2. The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $32.77 to $33.58 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.

3. Represents RSUs, each representing a contingent right to receive one ordinary share. 1/3 of the RSUs will vest on each of the first, second and third anniversaries of the vesting start date, subject to the Reporting Person's continued service through each such date.

4. Each RSU was granted on January 7, 2026 for no consideration.

5. 25% of the shares underlying the option will vest on Janaury 2, 2027, the one-year anniversary of the 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.

	/s/ Louise Kooij by Power of Attorney from Johannes Jacob Pieter Kastelein	01/07/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
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FAQ

What insider transactions did NewAmsterdam Pharma (NAMS) disclose in this Form 4?

The filing shows Johannes Jacob Pieter Kastelein, Chief Scientific Officer and director, sold 6,000 ordinary shares and received 25,500 RSUs plus options on 115,000 ordinary shares.

Why did the NewAmsterdam Pharma insider sell 6,000 shares?

The 6,000-share sale on January 5, 2026 was a pre-arranged transaction made solely to cover tax withholding obligations related to RSU vesting and was not a discretionary trade.

What equity awards did the NewAmsterdam Pharma CSO receive?

On January 7, 2026, the CSO received 25,500 RSUs granted for no consideration and an option to buy 115,000 ordinary shares at an exercise price of $35.45 per share.

How do the NewAmsterdam Pharma RSUs vest for the reporting person?

The 25,500 RSUs vest over three years, with 1/3 vesting on each of the first, second and third anniversaries of the vesting start date, subject to continued service.

What are the vesting terms of the NewAmsterdam Pharma stock options reported?

For the 115,000-share option, 25% vests on January 2, 2027, with the remaining shares vesting in equal monthly installments over the following three years, subject to continued service, and the option expires on January 7, 2036.

How many NewAmsterdam Pharma shares does the insider own after these transactions?

After the reported transactions, the insider beneficially owns 98,981 ordinary shares directly.