Net Power Inc.

11/06/2026 | Press release | Distributed by Public on 11/06/2026 17:12

Statement of Changes in Beneficial Ownership (Form 4)

FORM 4
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES 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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(Print or Type Responses)
1. Name and Address of Reporting Person *
Horstman Marc
2. Issuer Name and Ticker or Trading Symbol
Net Power Inc. [NPWR]
5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
President and COO
(Last) (First) (Middle)
C/O NET POWER INC., 11700 KATY FREEWAY, SUITE 700
3. Date of Earliest Transaction (Month/Day/Year)
11/04/2026
(Street)
HOUSTON, TX 77079
4. If Amendment, Date 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
(City) (State) (Zip)
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
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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 control number. SEC 1474 (9-02)
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 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
Stock Options(1) $2.13 11/04/2026 D 240,000 06/02/2026(2) 06/02/2030 Class A Common Stock 240,000 $ 0 0 D
Stock Options(1) $2.13 11/04/2026 A 240,000 06/02/2026(2) 06/02/2030 Class A Common Stock 240,000 $ 0 240,000 D

Reporting Owners

Reporting Owner Name / Address Relationships
Director 10% Owner Officer Other
Horstman Marc
C/O NET POWER INC.
11700 KATY FREEWAY, SUITE 700
HOUSTON, TX 77079
President and COO

Signatures

/s/ Marc Horstman 11/06/2026
**Signature of Reporting Person Date

Explanation of Responses:

* 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).
(1) On November 4, 2026, the Issuer's board of directors approved an amendment to the stock option granted to the reporting person on June 2, 2025, which extends the period during which the vested option may be exercised following certain terminations of service. The amendment did not change the number of shares subject to the option, its exercise price, its vesting date or its expiration date, and the reporting person paid no consideration for it. The amendment is reported as the deemed cancellation of the original option and the grant of the amended option, each of which is exempt under Rule 16b-3.
(2) The option became exercisable in full on June 2, 2026.
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure. Potential persons who are to respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB number.
Net Power Inc. published this content on November 06, 2026, and is solely responsible for the information contained herein. Distributed via EDGAR on November 06, 2026 at 23:12 UTC. If you believe the information included in the content is inaccurate or outdated and requires editing or removal, please contact us at [email protected]