ASP Isotopes Inc. 美股招股说明书（2025-06-02版）

Common Stock We are offering 7,518,797 shares of our common stock, par value $0.01 per share, at an offering price of $6.65 per share. Our common stock is listed on The Nasdaq Capital Market, or “Nasdaq,” under the symbol “ASPI.” On May 30, 2025, the lassale price of shares of our common stock on Nasdaq was $7.56 per share. Investing in our securities involves a high degree of risk. See “Risk Factors” beginning on page S-7 of this psupplement and in our filings with the Securities and Exchange Commission that are incorporated by reference in this p Neither the Securities and Exchange Commission nor any state securities commission has approved or disapprovedsecurities or passed upon the adequacy or accuracy of this prospectus supplement or the accompanying prospectus. Any repreto the contrary is a criminal offense. (1)We refer you to “Underwriting” beginning on page S-17 of this prospectus supplement for additional information regarding undecompensation. The underwriters expect to deliver the shares to purchasers on or about June3, 2025. Canaccord Genuity June2, 2025 ABOUT THIS PROSPECTUS SUPPLEMENT This prospectus supplement and the accompanying prospectus relate to the offering of our common stock. Before buying anyour common stock that we are offering, we urge you to carefully read this prospectus supplement, the accompanying prospectuswriting prospectus that we have authorized for use in connection with this offering, and the information incorporated by reference as This prospectus supplement and the accompanying prospectus are part of a “shelf” registration statement on Form S-3 (File286860) that was declared effective by the Securities and Exchange Commission, or the “SEC,” on May30, 2025. This document is cof two parts. The first part is this prospectus supplement, which describes the specific terms of this offering and also adds to, aninformation contained in, the accompanying prospectus and the documents incorporated by reference into this prospectus supplemeaccompanying prospectus. The second part, the accompanying prospectus, provides more general information, some of which may nothis offering. Generally, when we refer to this prospectus, we are referring to the combined document consisting of this prospectus suand the accompanying prospectus. In this prospectus supplement, as permitted by law, we “incorporate by reference” information fdocuments that we file with the SEC. This means that we can disclose important information to you by referring to those docum We have not, and the underwriters have not, authorized anyone to provide any information other than that contained or incorpreference in this prospectus supplement, the accompanying prospectus or in any free writing prospectus that we have authorizedconnection with this offering. We and the underwriters take no responsibility for, and can provide no assurance as to the reliability of,information that others may give you. We and the underwriters are not making an offer to sell or soliciting an offer to buy our securitjurisdiction in which an offer or solicitation is not authorized or in which the person making that offer or solicitation is not qualified t You should assume that the information appearing in this prospectus supplement, the accompanying prospectus, the dincorporated by reference into this prospectus supplement and the accompanying prospectus, and in any free writing prospectus tha Unless the context otherwise indicates, references in this prospectus to “we,” “our” and “us” refer to ASP Isotopes Inc., acorporation, and its consolidated subsidiaries taken as a whole. Table of Contents PROSPECTUS SUPPLEMENT SUMMARY This summary highlights selected information contained elsewhere in this prospectus supplement and the accompanying prospincorporated by reference in this prospectus supplement and the accompanying prospectus. This summary does not contain ainformation you should consider before investing in our common stock. You should read carefully this entire prospectus suppleaccompanying prospectus and any free writing prospectus, as well as the information incorporated by reference, before deciding winvest in shares of our common stock. You should pay special attention to the “Risk Factors” section beginning on page S-7 of this p Overview We are a development stage advanced materials company dedicated to the development of technology and processesuccessful, will allow for the enrichment of natural isotopes into higher concentration products, which could be used in several indusproprietary technologies, the Aerodynamic Separation Process (“ASP technology”) and Quantum Enrichment technology (“QE tech We have completed the commissioning phase and are commencing commercial production at our C-14 and Si-28 enrichmentin Pretoria, South Africa. We have also completed the commissioning phase and are commencing production of commercial samplesenriched Yb-176 at our Yb-176 enrichment facility in Pretoria, South Africa. Ou