Sec Form 4 Filing - Kastelein Johannes Jacob Pieter @ NewAmsterdam Pharma Co N.V. - 2024-03-26

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

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, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL OMB Number: 3235-0287 Expires: November 30, 2011 Estimated average burden hours per response... 0.5

1. Name and Address of Reporting Person Kastelein Johannes Jacob Pieter 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 (Last) (First) (Middle) C/O NEWAMSTERDAM PHARMA COMPANY N.V., GOOIMEER 2-35 3. Date of Earliest Transaction (MM/DD/YY) 03/26/2024 (Street) NAARDEN, P71411 DC 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 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 03/26/2024 M 201,673 A 201,673 I See footnote ( 2 ) Ordinary Shares 03/26/2024 F 11,197 ( 3 ) D $ 22.72 190,476 I See footnote ( 2 ) Ordinary Shares 03/26/2024 S 190,476 ( 4 ) D ( 5 ) $ 21.5 0 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 (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 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 (MM/DD/YY) 7. Title and Amount of Underlying Securities (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 of Derivative Security: 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 ) 03/26/2024 M 201,673 ( 6 ) 07/06/2031 Ordinary Shares 201,673 $ 0 970,229 I See footnote ( 7 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Kastelein Johannes Jacob Pieter C/O NEWAMSTERDAM PHARMA COMPANY N.V. GOOIMEER 2-35 NAARDEN, P71411 DC X Chief Scientific Officer Signatures /s/ Louise Kooij by Power of Attorney from Johannes Jacob Pieter Kastelein 03/27/2024 Signature of Reporting Person Date

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") through NAP PoolCo B.V. ("PoolCo") for the benefit of the Reporting Person. The Reporting Person exercises sole voting and investement control over the Ordinary Shares held by Futurum through PoolCo. PoolCo has no voting or investement control or pecuniary interest in the Ordinary Shares held on behalf of Futurum. ( 3 )Represents Ordinary Shares that were withheld to satisfy the exercise price due upon the exercise of the options. ( 4 )These shares were sold in multiple transactions at a price of $21.50 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 Ordinary Shares were sold by the Reporting Person pursuant to an exemption in a lock-up agreement, dated February 12, 2024, in order to satisfy certain tax liabilities. ( 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 PoolCo for the benefit of the Reporting Person. The Reporting Person exercises sole voting and investement control over the securities held by Futurum through PoolCo. PoolCo has no voting or investement control or pecuniary interest in the securities held on behalf of Futurum.

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).

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.