NewAmsterdam Pharma affiliate plans $3.48M sale

NewAmsterdam Pharma Co N.V.

Rhea-AI Filing Summary

NewAmsterdam Pharma Co N.V. (NAMS) is named as the issuer in a notice of proposed sale of restricted or control securities under Form 144. An affiliate associated with Johannes Jacob Pieter Kastelein, with sales expected by Futurum B.V., has filed to potentially sell up to 125,000 Ordinary Shares through J.P. Morgan Securities LLC on Nasdaq.

The filing lists an aggregate market value of 3,483,750 for these shares and states that 119,537,169 Ordinary Shares were outstanding. The approximate date of sale is given as 08/24/2026, with the shares acquired via option exercise for cash from the issuer and expected to be sold within the next 90 days.

Key Figures

Ordinary Shares to be sold: 125,000 shares Aggregate market value of shares: 3,483,750 Shares outstanding: 119,537,169 shares +2 more

5 metrics

Ordinary Shares to be sold 125,000 shares Maximum number of Ordinary Shares covered by the Form 144 notice

Aggregate market value of shares 3,483,750 Aggregate market value for the 125,000 Ordinary Shares to be sold

Shares outstanding 119,537,169 shares Ordinary Shares outstanding for NewAmsterdam Pharma Co N.V.

Approximate date of sale 08/24/2026 Approximate date of sale listed for the proposed Rule 144 transaction

Expected sale window next 90 days Remarks state shares are expected to be sold in the next 90 days by Futurum B.V.

Key Terms

Form 144, Rule 144, aggregate market value, attorney-in-fact

4 terms

Form 144 regulatory

"144: Filer Information 144: Issuer Information"

Form 144 is a document that investors must file with the government when they plan to sell a large number of shares of a company's stock. It helps ensure transparency so everyone knows how many shares are being sold and when, which can impact the stock's price.

Rule 144 regulatory

"See the definition of "person" in paragraph (a) of Rule 144."

Rule 144 is a U.S. securities regulation that sets conditions under which restricted or insider-held shares can be legally resold to the public, such as required holding periods, availability of public information, limits on how much can be sold at once, and certain filing requirements. For investors it matters because it determines when previously locked-up shares can enter the market — like a release valve that can increase supply, affect share price, and signal insider intent.

aggregate market value financial

"Ordinary Shares ... 125000 | 3483750 | 119537169 | 08/24/2026 | Nasdaq"

Aggregate market value is the combined price you would pay to buy all outstanding shares of a company or all companies in a group at current market prices — essentially the sum of each stock’s market capitalization. It matters to investors because it shows the overall size and weight of an investment or sector (like the total cost to buy every piece of a puzzle), helps compare scale across companies or markets, and influences index composition and risk exposure.

attorney-in-fact regulatory

"as agent and attorney-in-fact for Michael H. Davidson"

An attorney-in-fact is the person or entity given legal authority through a power of attorney to act on behalf of another for specific tasks, such as signing documents, voting shares, or handling transactions. For investors, this matters because it lets a trusted representative make timely decisions or complete paperwork when the owner cannot, much like handing keys to someone to run errands on your behalf—so checks on scope and limits of that authority are important.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What does the Form 144 filing disclose for NewAmsterdam Pharma Co N.V. (NAMS)?

It discloses a planned sale under Form 144 by an affiliate associated with Johannes Jacob Pieter Kastelein, covering up to 125,000 Ordinary Shares of NewAmsterdam Pharma Co N.V., to be sold through J.P. Morgan Securities LLC on Nasdaq.

How many NewAmsterdam Pharma (NAMS) shares are covered by this Form 144?

The notice covers up to 125,000 Ordinary Shares of NewAmsterdam Pharma Co N.V. These shares are expected to be sold in the next 90 days, with J.P. Morgan Securities LLC acting as the broker on Nasdaq.

What is the aggregate market value of the NAMS shares in this Form 144?

The filing lists an aggregate market value of 3,483,750 for the 125,000 Ordinary Shares covered by the notice of proposed sale under Rule 144.

When are the NewAmsterdam Pharma (NAMS) shares expected to be sold under this Form 144?

The approximate sale date is stated as 08/24/2026, and the remarks note that the shares are expected to be sold in the next 90 days by Futurum B.V., with John Kastelein as Director.

How many NewAmsterdam Pharma (NAMS) shares were outstanding according to this filing?

The Form 144 notice reports that there were 119,537,169 Ordinary Shares of NewAmsterdam Pharma Co N.V. outstanding, providing context for the proposed sale amount.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 08/24/2026 - 04:56 PM EDT Accepted by SEC EDGAR 08/24/2026 - 04:55 PM EDT Learn about SEC filing dates

Form 144 Filer Information	UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 144 NOTICE OF PROPOSED SALE OF SECURITIES PURSUANT TO RULE 144 UNDER THE SECURITIES ACT OF 1933
FORM 144

144: Filer Information

Filer CIK	0002000389
Filer CCC	XXXXXXXX
Is this a LIVE or TEST Filing?	LIVE TEST
Submission Contact Information
Name
Phone
E-Mail Address

144: Issuer Information

Name of Issuer	NewAmsterdam Pharma Company N.V.
SEC File Number	001-41562
Address of Issuer	Gooimeer 2-35 DC Naarden NETHERLANDS 1411
Phone	31-0-35-206-2971
Name of Person for Whose Account the Securities are To Be Sold	Kastelein Johannes Jacob Pieter
See the definition of "person" in paragraph (a) of Rule 144. Information is to be given not only as to the person for whose account the securities are to be sold but also as to all other persons included in that definition. In addition, information shall be given as to sales by all persons whose sales are required by paragraph (e) of Rule 144 to be aggregated with sales for the account of the person filing this notice.
Relationship to Issuer	Affiliate

144: Securities Information

Title of the Class of Securities To Be Sold	Name and Address of the Broker	Number of Shares or Other Units To Be Sold	Aggregate Market Value	Number of Shares or Other Units Outstanding	Approximate Date of Sale	Name the Securities Exchange
Ordinary Shares	J.P. Morgan Securities LLC 270 Park Avenue - 10th Floor New York NY 10017	125000	3483750	119537169	08/24/2026	Nasdaq

Furnish the following information with respect to the acquisition of the securities to be sold and with respect to the payment of all or any part of the purchase price or other consideration therefor:

144: Securities To Be Sold

Title of the Class	Date you Acquired	Nature of Acquisition Transaction	Name of Person from Whom Acquired	Is this a Gift?	Date Donor Acquired	Amount of Securities Acquired	Date of Payment	Nature of Payment *
Ordinary Shares	08/24/2026	Option Exercise	Issuer			125000	08/24/2026	Cash

* If the securities were purchased and full payment therefor was not made in cash at the time of purchase, explain in the table or in a note thereto the nature of the consideration given. If the consideration consisted of any note or other obligation, or if payment was made in installments describe the arrangement and state when the note or other obligation was discharged in full or the last installment paid.

Furnish the following information as to all securities of the issuer sold during the past 3 months by the person for whose account the securities are to be sold.

144: Securities Sold During The Past 3 Months

Nothing to Report

144: Remarks and Signature

Remarks	The shares represented on this filing are for shares expected to be sold in the next 90 days by Futurum B.V., John Kastelein as Director
Date of Notice	08/24/2026
Date of Plan Adoption or Giving of Instruction, If Relying on Rule 10b5-1	05/28/2026
ATTENTION:
The person for whose account the securities to which this notice relates are to be sold hereby represents by signing this notice that he does not know any material adverse information in regard to the current and prospective operations of the Issuer of the securities to be sold which has not been publicly disclosed. If such person has adopted a written trading plan or given trading instructions to satisfy Rule 10b5-1 under the Exchange Act, by signing the form and indicating the date that the plan was adopted or the instruction given, that person makes such representation as of the plan adoption or instruction date.
Signature	/s/ J.P. Morgan Securities LLC as agent and attorney-in-fact for Michael H. Davidson
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)