Net Power Inc.

Insider Trading Arrangements

During the three months ended September 30, 2026, none of our directors or “officers” (as such term is defined in Rule 16a-1(f) under the Exchange Act) adopted or terminated a “Rule 10b5-1 trading arrangement” or “non-Rule 10b5-1 trading arrangement” (as each term is defined in Item 408(a) of Regulation S-K).

Correction of Prior Disclosure

The Rule 10b5-1 trading arrangement adopted by Akash Patel, our former Chief Financial Officer, that we described in Part II, Item 5 of our Quarterly Report on Form 10-Q for the quarter ended September 30, 2024 was adopted on August 23, 2024, not August 26, 2024, as reported.

Amendment No. 1 to Agreement to Extend FNTP Date

The following disclosure is provided in lieu of a Current Report on Form 8-K under Item 1.01, Entry into a Material Definitive Agreement. On November 11, 2026, Net Power, LLC, a subsidiary of the Company, and Saulsbury Industries, Inc. entered into Amendment No. 1 to Agreement to Extend FNTP Date, which amends their Agreement to Extend FNTP Date, effective as of October 15, 2026, described in our Current Report on Form 8-K filed on October 22, 2026. The amendment extends from November 15, 2026 to November 20, 2026 the date by which the Post-closing Change Order (referred to in that report as the Fourth Amendment) and a limited notice to proceed must be executed, and the payments required under the limited notice to proceed made, for the $3.5 million contract termination payment to remain deferred. In the amendment, Saulsbury also confirmed that it had not demanded the termination payment, that the termination payment was not payable, and that it remained deferred under the Agreement to Extend FNTP Date as amended. The other terms of the Agreement to Extend FNTP Date are unchanged. The foregoing description is qualified in its entirety by reference to the amendment, which is filed as Exhibit 10.24 to this Report.