UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): September 15, 2025

Registrant’s telephone number, including area code: (202) 756-2245

 Not Applicable

(Former name or former address, if changed since last report.)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

Securities registered pursuant to Section 12(b) of the Act:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ☒

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act ☐ 

Item 7.01. Regulation FD Disclosure.

On September 15, 2025, ASP Isotopes Inc. (the “Company” or “ASP Isotopes”) extended the date for the fulfillment of the conditions to the previously announced offer by the Company to acquire 100% of the ordinary shares (excluding treasury shares) of Renergen Limited (“Renergen”), a South African company listed on the exchange operated by the JSE Limited and the Australian Securities Exchange, pursuant to a scheme of arrangement under South African law pursuant to which Renergen shareholders will receive 0.09196 new ASP Isotopes shares for each Renergen share held on the record date (the “Scheme”).

The Company has extended the longstop date from September 30, 2025 to November 28, 2025 in order to allow the parties additional time to satisfy conditions to closing relating to the receipt of the remaining required regulatory approval and certain third party consents.  As of September 15, 2025, the implementation of the Scheme remained subject to the approval of the Financial Surveillance Department of the South African Reserve Bank (FinSurv) as provided for in the South African Exchange Control Regulations (in terms of the South African Currency and Exchanges Act, 1933).  The Company and Renergen continue to pursue a timely approval of the Scheme with FinSurv and certain third parties in order to implement the Scheme as promptly as possible.

Forward Looking Statements

This Form 8-K contains “forward-looking statements” within the meaning of the safe harbor provisions of the U.S. Private Securities Litigation Reform Act of 1995. Forward-looking statements can be identified by words like “may,” “will,” “likely,” “should,” “expect,” “anticipate,” “future,” “plan,” “believe,” “intend,” “goal,” “seek,” “estimate,” “project,” “continue,” and variations of such words and similar expressions. These forward-looking statements are not guarantees of future performance and involve risks, assumptions, and uncertainties, including, but not limited to, risks related to: (i) the implementation of the Scheme in the anticipated timeframe or at all; (ii) the satisfaction of the Scheme conditions; (iii) the failure to obtain necessary regulatory approvals; (iv) the ability to realize the anticipated benefits of the proposed acquisition of Renergen; (v) the ability to successfully integrate the businesses; (vi) disruption from the proposed acquisition of Renergen making it more difficult to maintain business and operational relationships; (vii) the negative effects of this announcement or the consummation of the proposed acquisition of Renergen on the market price of Renergen’s or ASPI’s securities; (viii) significant transaction costs and unknown liabilities; (ix) litigation or regulatory actions related to the proposed acquisition of Renergen; and (x) such other factors as are set forth in the periodic reports filed by ASPI with the U.S. Securities and Exchange Commission (the “SEC”), including but not limited to those described under the heading “Risk Factors” in its annual reports on Form 10-K, quarterly reports on Form 10-Q and any other filings made with the SEC from time to time, which are available via the SEC’s website at www.sec.gov. Should one or more of these risks or uncertainties materialize, or should underlying assumptions prove incorrect, actual results may vary materially from those indicated or anticipated by these forward-looking statements. Therefore, you should not rely on any of these forward-looking statements.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.