Sec Form 4 Filing - Beauchamp Cynda @ NET Power Inc. - 2025-10-31

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

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1. Name and Address of Reporting Person Beauchamp Cynda 2. Issuer Name and Ticker or Trading Symbol NET Power Inc. [ NPWR] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) 8 THE GREEN STE B 3. Date of Earliest Transaction (MM/DD/YY) 10/31/2025 (Street) DOVER, DE19901 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 Class A Common Stock 10/31/2025 S 18,116 D $ 4.0527 ( 1 ) 1,847,130 I See Footnote ( 2 ) Class A Common Stock 11/02/2025 J( 2 ) 1,847,130 D 0 I See Footnotes ( 2 ) ( 3 ) Class B Common Stock 11/02/2025 J( 2 ) 22,729,880 D 0 I See Footnotes ( 2 ) ( 3 )

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 Class A Units of NET Power Operations LLC ( 3 ) 11/02/2025 J( 2 ) 22,729,880 ( 3 ) ( 3 ) Class A Common Stock 22,729,880 ( 2 ) 0 I See Footnotes ( 2 ) ( 3 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Beauchamp Cynda 8 THE GREEN STE B DOVER, DE19901 X Signatures /s/ Cynda Beauchamp 11/04/2025 Signature of Reporting Person Date

Explanation of Responses:

( 1 )The price reported reflects the weighted average sales price. The shares of Class A Common Stock were sold in multiple trades at prices ranging from $4.05 to $4.06. NPEH, LLC ("NPEH") will provide upon request to the SEC, the Issuer or security holder of the Issuer, full information regarding the number of shares sold at each separate price. ( 2 )The securities reported in this Form 4 are directly held by NPEH, a limited liability company of which the Reporting Person was the indirect majority owner. On November 2, 2025, the Reporting Person sold 100% of the equity interests of 8RCH, LLC, which holds 50% of the equity interests of each of Tillandsia, Inc. ("Tillandsia"), Areca, Inc. ("Areca") and Chamaedorea, Inc. ("Chamaedoria"). Tillandsia, Areca and Chamaedorea own approximately 18.6%, 25.77% and 24.11%, respectively, of the voting units of 8 Rivers Capital, LLC ("8 Rivers"). 8 Rivers is the manager and owns approximately 91.4% of NPEH. ( 3 )For each Class A Unit of Net Power Operations LLC, NPEH owns one corresponding share of Class B Common Stock of the Issuer. The Class A Units of NET Power Operations LLC are exchangeable (together with the cancellation of a corresponding number of shares of the Issuer's Class B Common Stock) into shares of the Issuer's Class A Common Stock on a one-for-one basis or, at the Issuer's election, cash, and have no expiration 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).

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