ASPI / ASP Isotopes Inc. - SEC-Einreichungen, Jahresbericht, Proxy Statement

FORM 8-K Item 7.01 Regulation FD Disclosure. Item 9.01 Financial Statements and Exhibits.

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): May 26, 2026 ASP Isotopes Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-41555 87-2618235 (State or Other Jurisdiction of Incorporation) (Commission File Num

EX-99.1

EXHIBIT 99.1 ASP Isotopes Implements Engineering Enhancements to Silicon-28 Enrichment Facility; Successfully Restarts First 18 Stages of Silicon-28 Enrichment Facility; Commercial Shipments of Enriched Silicon-28 Expected to Commence in Q3 2026 ASP Isotopes has previously announced that it has signed three commercial contracts for the supply of enriched Silicon-28 to U.S.-based customers, and exp

Calculation of Filing Fee Tables FORM S-8 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 ASP ISOTOPES INC. (Exact Name of Registrant as Specified in its Charter) Table 1: Newly Registered Securities

EXHIBIT 107 Calculation of Filing Fee Tables FORM S-8 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 ASP ISOTOPES INC.

Calculation of Filing Fee Tables FORM S-8 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 ASP ISOTOPES INC. (Exact Name of Registrant as Specified in its Charter) Table 1: Newly Registered Securities

EXHIBIT 107 Calculation of Filing Fee Tables FORM S-8 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 ASP ISOTOPES INC.

As filed with the Securities and Exchange Commission on May 20, 2026

As filed with the Securities and Exchange Commission on May 20, 2026 Registration No.

As filed with the Securities and Exchange Commission on May 20, 2026

As filed with the Securities and Exchange Commission on May 20, 2026 Registration No.

REQUEST FOR WAIVER

Exhibit 10.15 CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS DOCUMENT, MARKED AT THE APPROPRIATE PLACE WITH THREE ASTERISKS [***], HAS BEEN OMITTED BECAUSE IT IS BOTH (I) NOT MATERIAL AND (II) IS THE TYPE THAT THE REGISTRANT TREATS AS PRIVATE AND CONFIDENTIAL. REQUEST FOR WAIVER August 30, 2024 United States International Development Finance Corporation 110 New York Avenue, N.W. Washington, D.

REQUEST FOR CONSENT AND WAIVER TETRA4 PROPREITARY LIMITED

Exhibits 10.16 CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS DOCUMENT, MARKED AT THE APPROPRIATE PLACE WITH THREE ASTERISKS [***], HAS BEEN OMITTED BECAUSE IT IS BOTH (I) NOT MATERIAL AND (II) IS THE TYPE THAT THE REGISTRANT TREATS AS PRIVATE AND CONFIDENTIAL. REQUEST FOR CONSENT AND WAIVER December 9, 2024 United States International Development Finance Corporation 110 New York Avenue, N.W.

AMENDMENT/VARIATION OF A PRODUCTION RIGHT Granted in terms of section 102 of the Mineral and Petroleum Resources Act, 2002 (Act No. 28 of 2002)

Exhibit 10.21 12/4/07PR AMENDMENT/VARIATION OF A PRODUCTION RIGHT Granted in terms of section 102 of the Mineral and Petroleum Resources Act, 2002 (Act No. 28 of 2002) 2 12/4/07PR Protocol No: 9/2021 NOTARIAL DEED OF AMENDMENT/VARIATION OF A PRODUCTION RIGHT GRANTED IN TERMS OF SECTION 102 OF THE MINERAL AND PETROLEUM RESOURCES DEVELOPMENT ACT, 28 OF 2002 BE IT HEREBY MADE KNOWN: That on this 17th

REQUEST FOR CONSENT AND WAIVER

Exhibit 10.18 CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS DOCUMENT, MARKED AT THE APPROPRIATE PLACE WITH THREE ASTERISKS [***], HAS BEEN OMITTED BECAUSE IT IS BOTH (I) NOT MATERIAL AND (II) IS THE TYPE THAT THE REGISTRANT TREATS AS PRIVATE AND CONFIDENTIAL. Execution Version REQUEST FOR CONSENT AND WAIVER November 25, 2025 United States International Development Finance Corporation 110 New

REQUEST FOR CONSENTS AND WAIVER Re: Loan No. 9000083212 Tetra4 Helium Project – Request for Consent to Mahlako Subscription, Restricted Payment and Waiver of Restricted Payment Conditions TETRA4 PROPRIETARY LIMITED RENERGEN LIMITED TETRA4 PROPRIETARY

Exhibit 10.13 CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS DOCUMENT, MARKED AT THE APPROPRIATE PLACE WITH THREE ASTERISKS [***], HAS BEEN OMITTED BECAUSE IT IS BOTH (I) NOT MATERIAL AND (II) IS THE TYPE THAT THE REGISTRANT TREATS AS PRIVATE AND CONFIDENTIAL. REQUEST FOR CONSENTS AND WAIVER January 12, 2024 United States International Development Finance Corporation 110 New York Avenue, N.W.

1. Definitions. 2. Agreement Among the Company, the Investors and the Key Holders. 3. Exempt Transfers. 5. Lock-Up.

Exhibit 10.28 RIGHT OF FIRST REFUSAL AND CO-SALE AGREEMENT This Right of First Refusal and Co-Sale Agreement (this “Agreement”) is made as of January 26, 2026, by and among Opeongo, Inc., a Delaware corporation (the “Company”), the Investors (as defined below) and the Key Holders (as defined below). RECITALS WHEREAS, each Key Holder is the beneficial owner of shares of Capital Stock (as defined be

1. Purchase and Sale of Preferred Stock.

Exhibit 10.26 SERIES SEED-1 PREFERRED STOCK PURCHASE AGREEMENT This Series Seed-1 Preferred Stock Purchase Agreement (this “Agreement”) is made as of January 26, 2026, by and between Opeongo, Inc., a Delaware corporation (the “Company”), and ASP Isotopes Inc., a Delaware corporation (the “Purchaser”). The parties hereby agree as follows: 1. Purchase and Sale of Preferred Stock. 1.1 Sale and Issuan

FORM 8-K Item 7.01 Regulation FD Disclosure.

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): May 20, 2026 ASP Isotopes Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-41555 87-2618235 (State or Other Jurisdiction of Incorporation) (Commission File Num

1. Voting Provisions Regarding the Board. 2. Vote to Increase Authorized Common Stock. Each Stockholder agrees to vote or cause to be voted all Shares owned by such Stockholder, or over which such Stockholder has voting control, from time to time and

Exhibit 10.29 VOTING AGREEMENT This Voting Agreement (this “Agreement”) is made as of January 26, 2026, by and among Opeongo, Inc., a Delaware corporation (the “Company”), the Investors (as defined below), the Founders (as defined below) and other Stockholders (as defined below). RECITALS WHEREAS, the Company and ASP Isotopes Inc., a Delaware corporation (the “Initial Investor”), are parties to th

AS WITNESS: AS WITNESS:

Exhibit 10.22 12/4/07PR AMENDMENT/VARIATION OF A PRODUCTION RIGHT Granted in terms of section 102 of the Mineral and Petroleum Resources Act, 2002 (Act No. 28 of 2002) 2 12/4/07PR Protocol No: 75 /2024 NOTARIAL DEED OF AMENDMENT/VARIATION OF A PRODUCTION RIGHT GRANTED IN TERMS OF SECTION 102 OF THE MINERAL AND PETROLEUM RESOURCES DEVELOPMENT ACT, 28 OF 2002 BE IT HEREBY MADE KNOWN: That on this 15

3. Information and Observer Rights.

Exhibit 10.27 INVESTORS’ RIGHTS AGREEMENT This Investors’ Rights Agreement (this “Agreement”) is made as of January 26, 2026, by and among Opeongo, Inc., a Delaware corporation (the “Company”), ASP Isotopes Inc., a Delaware corporation (the “Initial Investor”), the Key Holders (as defined below), Yeda Research and Development Company Limited, a company duly registered under the laws of Israel (“Ye

EXPLORATION RIGHT HIGHLAND EXPLORATION AND PRODUCTION (PTY) LTD Granted in terms of Section 80 of the Mineral and Petroleum Resources Development Act, 2002 (Act No. 28 of 2002)

Exhibit 10.24 Ref No: 12/3/1/94/1 EXPLORATION RIGHT HIGHLAND EXPLORATION AND PRODUCTION (PTY) LTD Granted in terms of Section 80 of the Mineral and Petroleum Resources Development Act, 2002 (Act No. 28 of 2002) Ref No: 12/3/1/94/1 TABLE OF CONTENTS Clause Title Page Preamble 4 1. Definitions and Interpretations 6-9 2. Granting of the Right 10 3. Exploration Area 10 4. Exclusive Right to Apply for

REQUEST FOR CONSENT U.S INTERNATIONAL DEVELOPMENT FINANCE CORPORATION

Exhibit 10.14 CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS DOCUMENT, MARKED AT THE APPROPRIATE PLACE WITH THREE ASTERISKS [***], HAS BEEN OMITTED BECAUSE IT IS BOTH (I) NOT MATERIAL AND (II) IS THE TYPE THAT THE REGISTRANT TREATS AS PRIVATE AND CONFIDENTIAL. EXECUTION VERSION REQUEST FOR CONSENT March 12, 2024 United States International Development Finance Corporation 110 New York Avenue, N

FIRST ADDENDUM TO THE TERM LOAN FACILITY AGREEMENT ASP ISOTOPES INCORPORATED ASP ISOTOPES SOUTH AFRICA PROPRIETARY LIMITED RENERGEN LIMITED each hereinafter referred to individually as a Party and collectively as the Parties.

Exhibit 10.1 FIRST ADDENDUM TO THE TERM LOAN FACILITY AGREEMENT Between ASP ISOTOPES INCORPORATED ("ASPI") and ASP ISOTOPES SOUTH AFRICA PROPRIETARY LIMITED ("Lender") and RENERGEN LIMITED ("Borrower") each hereinafter referred to individually as a Party and collectively as the Parties. Table of Contents Table of Contents 1. DEFINITIONS AND INTERPRETATION 3 2. INTRODUCTION 3 3. AMENDMENT 3 4. CONF

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q (Mark One)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2026 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-41555 ASP Isotopes Inc.

THIRD ADDENDUM TO THE TERM LOAN FACILITY AGREEMENT ASP ISOTOPES INCORPORATED ASP ISOTOPES SOUTH AFRICA PROPRIETARY LIMITED RENERGEN LIMITED each hereinafter referred to individually as a Party and collectively as the Parties.

Exhibit 10.3 THIRD ADDENDUM TO THE TERM LOAN FACILITY AGREEMENT Between ASP ISOTOPES INCORPORATED ("ASPI") and ASP ISOTOPES SOUTH AFRICA PROPRIETARY LIMITED ("Lender") and RENERGEN LIMITED ("Borrower") each hereinafter referred to individually as a Party and collectively as the Parties. Table of Contents Table of Contents 1. DEFINITIONS AND INTERPRETATION 3 2. INTRODUCTION 3 3. AMENDMENT 3 4. CONF

RECITALS ARTICLE I WAIVERS ARTICLE II REPRESENTATIONS AND WARRANTIES; UNDERTAKINGS AND AMENDMENTS ARTICLE III MISCELLANEOUS UNITED STATES INTERNATIONAL DEVELOPMENT FINANCE CORPORATION

Exhibit 10.17 CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS DOCUMENT, MARKED AT THE APPROPRIATE PLACE WITH THREE ASTERISKS [***], HAS BEEN OMITTED BECAUSE IT IS BOTH (I) NOT MATERIAL AND (II) IS THE TYPE THAT THE REGISTRANT TREATS AS PRIVATE AND CONFIDENTIAL. Execution Version Request for Waiver (DFC/9000083212) This Waiver (this “Waiver”) is made and entered into as of April 9 , 2025 by and

LIQUIFIED NATURAL GAS SUPPLY AGREEMENT TETRA4 PROPRIETARY LIMITED Registration 2005/012157/07 (the “Company”) having its head office situated at 1 Bompas Road Dunkeld West CONSOL GLASS PROPRIETARY LIMITED Registration Number: 2006/034503/07 (the “Cus

Exhibit 10.25 CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS DOCUMENT, MARKED AT THE APPROPRIATE PLACE WITH THREE ASTERISKS [***], HAS BEEN OMITTED BECAUSE IT IS BOTH (I) NOT MATERIAL AND (II) IS THE TYPE THAT THE REGISTRANT TREATS AS PRIVATE AND CONFIDENTIAL. (EXECUTION VERSION – 17/06/2022) LIQUIFIED NATURAL GAS SUPPLY AGREEMENT between TETRA4 PROPRIETARY LIMITED Registration 2005/012157/07

EXPLORATION right (Ref no 30/5/2/3/2/32 ER) Granted in terms of section 80 of the Mineral and Petroleum Resources Development Act, 2002 (Act No. 28 of 2002)

Exhibit 10.23 D0005 Exploration Right- Petroleum Agency SA-2007 EXPLORATION right (Ref no 30/5/2/3/2/32 ER) Granted in terms of section 80 of the Mineral and Petroleum Resources Development Act, 2002 (Act No. 28 of 2002) Exploration Right Text- Petroleum Agency SA-2007 30/5/2/3/2/32ER TABLE OF CONTENTS Clause Title Page Preamble 1. Definitions and Interpretations 06-10 2. Granting of the Right 10

SECOND ADDENDUM TO THE TERM LOAN FACILITY AGREEMENT ASP ISOTOPES INCORPORATED ASP ISOTOPES SOUTH AFRICA PROPRIETARY LIMITED RENERGEN LIMITED each hereinafter referred to individually as a Party and collectively as the Parties.

Exhibit 10.2 SECOND ADDENDUM TO THE TERM LOAN FACILITY AGREEMENT Between ASP ISOTOPES INCORPORATED ("ASPI") and ASP ISOTOPES SOUTH AFRICA PROPRIETARY LIMITED ("Lender") and RENERGEN LIMITED ("Borrower") each hereinafter referred to individually as a Party and collectively as the Parties. Table of Contents Table of Contents 1. DEFINITIONS AND INTERPRETATION 3 2. INTRODUCTION 3 3. AMENDMENT 3 4. CON

Production Right - Execution version

Exhibit 10.20 Production Right - Execution version PRODUCTION RIGHT Granted in terms of Section 84(1) of the Mineral and Petroleum Resources Development Act, 2002 (Act No. 28 of 2002) Production Right - Execution version TABLE OF CONTENTS Clause Title Page Preamble 1. Definitions and Interpretation 7 2. Granting of the Production Right 12 3. Production Area 12 4. Exclusive Right to Apply for Separ

OMB APPROVAL

OMB APPROVAL OMB Number: 3235-0058 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Expires: September 30, 2028 Estimated average burden Washington, D.

Quantum Leap Energy Enters into Memorandum of Understanding with European Nuclear Technology Company for Advanced Nuclear Fuel Supply Collaboration MOU establishes framework for collaboration with the goal to supply HALEU to European advanced reactor

EXHIBIT 99.1 Quantum Leap Energy Enters into Memorandum of Understanding with European Nuclear Technology Company for Advanced Nuclear Fuel Supply Collaboration MOU establishes framework for collaboration with the goal to supply HALEU to European advanced reactor developer, beginning 2028 DALLAS, May 11, 2026 - ASP Isotopes Inc. (NASDAQ: ASPI) (“ASPI”) today announced that Quantum Leap Energy LLC

FORM 8-K Item 7.01 Regulation FD Disclosure. Item 9.01 Financial Statements and Exhibits.

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): May 11, 2026 ASP Isotopes Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-41555 87-2618235 (State or Other Jurisdiction of Incorporation) (Commission File Num

Quantum Leap Energy Appoints Dr. Peter Fiske to Strategic Advisory Board Technology Commercialization Leader Expected to Enhance QLE's Government Partnerships and Advanced Materials Strategy

EXHIBIT 99.1 Quantum Leap Energy Appoints Dr. Peter Fiske to Strategic Advisory Board Technology Commercialization Leader Expected to Enhance QLE's Government Partnerships and Advanced Materials Strategy DALLAS, May 6, 2026 - ASP Isotopes Inc. (NASDAQ: ASPI) (“ASPI”) today announced that Quantum Leap Energy LLC ("QLE" or the "Company"), a wholly-owned subsidiary of ASPI dedicated to advancing inno

FORM 8-K Item 7.01 Regulation FD Disclosure. Item 9.01 Financial Statements and Exhibits.

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): May 06, 2026 ASP Isotopes Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-41555 87-2618235 (State or Other Jurisdiction of Incorporation) (Commission File Num

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K/A (Amendment No. 1)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K/A (Amendment No. 1) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the year ended December 31, 2025 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number 001-41555 ASP Isotopes

ASP Isotopes Inc. Provides Business Update First Commercial Shipments Expected Across Multiple Isotopes in 2026 Expect to Obtain Helium Phase 1 Nameplate Capacity in Q3 2026 EBITDA Target of Greater Than $300 Million in 2031 Cash, Cash Equivalents an

EXHIBIT 99.1 ASP Isotopes Inc. Provides Business Update First Commercial Shipments Expected Across Multiple Isotopes in 2026 Expect to Obtain Helium Phase 1 Nameplate Capacity in Q3 2026 EBITDA Target of Greater Than $300 Million in 2031 Cash, Cash Equivalents and Short-Term Marketable Securities of $333 million as of December 31, 2025 Business Update Conference Call Scheduled for 8:00 AM ET on Ap

CORPORATE OVERVIEW

EXHIBIT 99.3

BUSINESS UPDATE CALL PRESENTATION

EXHIBIT 99.2

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): April 13, 2026

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): April 13, 2026 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission File N

ASP Isotopes Inc. Subsidiaries of the Registrant

EXHIBIT 21.1 ASP Isotopes Inc. Subsidiaries of the Registrant The following is a list of subsidiaries of ASP Isotopes Inc. as of March 31, 2026: Subsidiaries* Place of Incorporation ASP Isotopes Guernsey Limited (formerly, PDS-Photonica Holdings (Guernsey) Limited) Guernsey ASP Isotopes South Africa (Proprietary) Limited (formerly, PDS Photonica Holdings South Africa (PTY) Limited) South Africa En

INDUSTRIAL DEVELOPMENT CORPORATION OF SOUTH AFRICA LIMITED AUTHORISED SIGNATORY AUTHORISED SIGNATORY FOR: TETRA4 PROPRIETARY LIMITED

Exhibit 10.42 19 Fredman Drive, Sandown 2196 PO Box 784055, Sandton 2146, South Africa Tel: +27 11 269 3000 Fax: +27 11 269 3116 www.idc.co.za Date: 1 September 2025 Tetra4 Proprietary Limited 4 Bompas Road Dunkeld West Johannesburg Attention: Stefano Marani Email: [email protected] Dear Sirs Ref: MolokoM/KS AMENDMENT TO THE LOAN AGREEMENT ENTERED INTO BETWEEN TETRA4 PROPRIETARY LIMITED AND I

The Borrower shall apply all amounts borrowed by it under the Facility towards:

Exhibit 10.49 Certain identified information has been excluded because it is both not material and is the type of information the registrant treats as private or confidential. Redactions are indicated by [***]. The MARC Tower 1 129 Rivonia Road Sandton Johannesburg South Africa 2196 P O Box 783347 Sandton South Africa 2146 Docex 152 Randburg tel +2711 269 7600 [email protected] ENSafrica.com AMEN

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the year ended December 31, 2025 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number 001-41555 ASP Isotopes Inc. (Exact name of

ARTICLE I DEFINITIONS AND INTERPRETATION ARTICLE II ARTICLE III REPRESENTATIONS AND WARRANTIES ARTICLE IV ARTICLE V ARTICLE VI AFFIRMATIVE COVENANTS ARTICLE VII NEGATIVE COVENANTS ARTICLE VIII DEFAULTS AND REMEDIES ARTICLE IX MISCELLANEOUS SECTION 9.

Exhibit 10.43 FINANCE AGREEMENT between TETRA4 PROPRIETARY LIMITED and OVERSEAS PRIVATE INVESTMENT CORPORATION Dated as of August 20, 2019 OPIC/9000083212 TABLE OF CONTENTS Page ARTICLE I DEFINITIONS AND INTERPRETATION 1 SECTION 1.01. Definitions and Interpretation 1 ARTICLE II AMOUNT AND TERMS OF THE LOAN 1 SECTION 2.01. Amount and Disbursement 1 SECTION 2.02. Interest; Default Interest 1 SECTION

LOAN AGREEMENT Parties: INDUSTRIAL DEVELOPMENT CORPORATION OF SOUTH AFRICA LIMITED (a corporation

Exhibit 10.40 LOAN AGREEMENT Parties: INDUSTRIAL DEVELOPMENT CORPORATION OF SOUTH AFRICA LIMITED (a corporation established under Section 2 of the Industrial Development Corporation Act 1940 (Act No. 22 of 1940)) ("Lender") 19 Fredman Drive Sandown 2196 Email: [email protected] Attention: Head: Legal Services Department and TETRA 4 PROPRIETARY LIMITED (registration number: 2005/012157/07) (a pr

ASP ISOTOPES INC. INSIDER TRADING POLICY As adopted by the Board of Directors as of September 13, 2025

Exhibit 19.1 ASP ISOTOPES INC. INSIDER TRADING POLICY As adopted by the Board of Directors as of September 13, 2025 DOCPROPERTY DOCXDOCID DMS=IManage Format=<>.<>/<>v.<>169629.00001/151339355v.2 Table of Contents Page Section 1. All Employees, Officers, Directors and their Family Members and Affiliates Are Subject to this Policy 1 Section 2. Trading in ASP Isotopes Securities While in Possession o

AMENDMENT NO. 4 FINANCE AGREEMENT TETRA4 PROPRIETARY LIMITED U.S. INTERNATIONAL DEVELOPMENT FINANCE CORPORATION AMENDMENT NO. 4 TO FINANCE AGREEMENT

Exhibit 10.47 AMENDMENT NO. 4 to FINANCE AGREEMENT between TETRA4 PROPRIETARY LIMITED and U.S. INTERNATIONAL DEVELOPMENT FINANCE CORPORATION Dated as of August 24, 2021 DFC/9000083212 AMENDMENT NO. 4 TO FINANCE AGREEMENT THIS AMENDMENT NO. 4 TO FINANCE AGREEMENT, dated as of August 24, 2021 (this “Amendment”), is made between TETRA4 PROPRIETARY LIMITED, a limited liability company duly registered

TETRA4 PROPRIETARY LIMITED

Exhibit 10.44 AMENDMENT NO. 1 to FINANCE AGREEMENT between TETRA4 PROPRIETARY LIMITED and U.S. INTERNATIONAL DEVELOPMENT FINANCE CORPORATION Dated as of March 30, 2020 DFC/9000083212 AMENDMENT NO. 1 TO FINANCE AGREEMENT THIS AMENDMENT NO. 1 TO FINANCE AGREEMENT, dated as of March 30, 2020 (this “Amendment”), is made between TETRA4 PROPRIETARY LIMITED, a limited liability company duly registered an

EXECUTION VERSION FINANCE AGREEMENT TETRA4 PROPRIETARY LIMITED UNITED STATES INTERNATIONAL DEVELOPMENT FINANCE CORPORATION AMENDMENT NO. 2 TO FINANCE AGREEMENT

Exhibit 10.45 EXECUTION VERSION AMENDMENT NO. 2 to FINANCE AGREEMENT between TETRA4 PROPRIETARY LIMITED and UNITED STATES INTERNATIONAL DEVELOPMENT FINANCE CORPORATION Dated as of April 28, 2020 DFC/9000083212 AMENDMENT NO. 2 TO FINANCE AGREEMENT THIS AMENDMENT NO. 2 TO FINANCE AGREEMENT, dated as of April 28, 2020 (this “Amendment”), is made between TETRA4 PROPRIETARY LIMITED, a limited liability

Exhibit 10.54 SECOND AMENDMENT TO EXECUTIVE EMPLOYMENT AGREEMENT

Exhibit 10.54 SECOND AMENDMENT TO EXECUTIVE EMPLOYMENT AGREEMENT This Second Amendment to Executive Employment Agreement, dated as of April 5, 2024 (the "Second Amendment"), is made and entered into by and between ASP Isotopes (Guernsey) Limited, a Guernsey corporation headquartered at Anson Court, La Route des Camps, St. Martin, Guernsey, GY4 6AD ("Company"), and Paul Mann, an individual ("Execut

1

EXHIBIT 99.1 ASP Isotopes to Host Business Update Conference Call on April 13, 2026, at 8:00 AM ET DALLAS, April 10, 2026 - ASP Isotopes Inc. (NASDAQ: ASPI) ("ASP Isotopes" or the "Company"), an advanced materials company focused on developing technologies and processes for the production of critical materials used in multiple industries, today announced that Paul Mann, Executive Chairman and Chie

AMENDMENT NO. 3 FINANCE AGREEMENT TETRA4 PROPRIETARY LIMITED UNITED STATES INTERNATIONAL DEVELOPMENT FINANCE CORPORATION AMENDMENT NO. 3 TO FINANCE AGREEMENT

Exhibit 10.46 AMENDMENT NO. 3 to FINANCE AGREEMENT between TETRA4 PROPRIETARY LIMITED and UNITED STATES INTERNATIONAL DEVELOPMENT FINANCE CORPORATION Dated as of February 26, 2021 DFC/9000083212 AMENDMENT NO. 3 TO FINANCE AGREEMENT THIS AMENDMENT NO. 3 TO FINANCE AGREEMENT, dated as of February 26, 2021 (this “Amendment”), is made between TETRA4 PROPRIETARY LIMITED, a limited liability company dul

AMENDMENT NO. 5 FINANCE AGREEMENT TETRA4 PROPRIETARY LIMITED UNITED STATES INTERNATIONAL DEVELOPMENT FINANCE CORPORATION AMENDMENT NO. 5 TO FINANCE AGREEMENT

Exhibit 10.48 AMENDMENT NO. 5 to FINANCE AGREEMENT between TETRA4 PROPRIETARY LIMITED and UNITED STATES INTERNATIONAL DEVELOPMENT FINANCE CORPORATION Dated as of December 16, 2021 DFC/9000083212 AMENDMENT NO. 5 TO FINANCE AGREEMENT THIS AMENDMENT NO. 5 TO FINANCE AGREEMENT, dated as of December 16, 2021 (this “Amendment”), is made between TETRA4 PROPRIETARY LIMITED, a limited liability company dul

19 Fredman Drive, Sandown 2196

Exhibit 10.41 19 Fredman Drive, Sandown 2196 PO Box 784055, Sandton 2146, South Africa Tel: +27112693000 Fax: +27112693116 www.idc.co.za Date: 10 October 2023 Tetra4 Proprietary Limited 25 Minerva Ave Glenadrienne Sandton 2196 Email: [email protected] Attention: Stefano Marani Dear Sirls Ref: Moloko Masangane/sr AMENDMENT TO THE LOAN AGREEMENT ENTERED INTO BETWEEN TETRA4 PROPRIETARY LIMITED A

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): April 10, 2026

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): April 10, 2026 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission File N

OMB APPROVAL

OMB APPROVAL OMB Number: 3235-0058 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Expires: September 30, 2028 Estimated average burden Washington, D.

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): March 24, 2026

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): March 24, 2026 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission File N

UNAUDITED PRO FORMA CONDENSED COMBINED FINANCIAL STATEMENTS

EXHIBIT 99.3 UNAUDITED PRO FORMA CONDENSED COMBINED FINANCIAL STATEMENTS ASP Isotopes Inc. (the “Company” or “ASP Isotopes”) acquired the issued share capital of Renergen Limited, a public company incorporated under the laws of the Republic of South Africa (“Renergen”), on January 6, 2025 by issuing new shares of ASP Isotopes common stock to Renergen shareholders at the ratio of 0.09196 shares of

RENERGEN LIMITED Incorporated in the Republic of South Africa (“Renergen” or “the Company” or together with its subsidiaries “the Group”) REVIEWED INTERIM CONSOLIDATED FINANCIAL STATEMENTS FOR THE SIX MONTHS ENDED 31 AUGUST 2025

EXHIBIT 99.2 RENERGEN LIMITED Incorporated in the Republic of South Africa (“Renergen” or “the Company” or together with its subsidiaries “the Group”) REVIEWED INTERIM CONSOLIDATED FINANCIAL STATEMENTS FOR THE SIX MONTHS ENDED 31 AUGUST 2025 CONTENTS INTERIM CONSOLIDATED STATEMENT OF FINANCIAL POSITION. 2 INTERIM CONSOLIDATED STATEMENT OF PROFIT OR LOSS AND OTHER COMPREHENSIVE LOSS. 3 INTERIM CONS

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K/A (Amendment No. 1) CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): January 6, 20

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K/A (Amendment No. 1) CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): January 6, 2026 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporatio

ASP Isotopes Announces Strategic Collaboration Between Quantum Leap Energy and University of Bristol to Design Advanced Laser Research Facility Collaboration to develop a cutting-edge lithium laser enrichment research facility in the UK

EXHIBIT 99.1 ASP Isotopes Announces Strategic Collaboration Between Quantum Leap Energy and University of Bristol to Design Advanced Laser Research Facility Collaboration to develop a cutting-edge lithium laser enrichment research facility in the UK DALLAS, March 24, 2026 - ASP Isotopes Inc. (NASDAQ: ASPI) (“ASPI”) today announced that a UK subsidiary of Quantum Leap Energy LLC (“QLE”), a wholly-o

RISK FACTORS RELATED TO RENERGEN

EXHIBIT 99.1 RISK FACTORS RELATED TO RENERGEN Risks Related to the Expansion of the Virginia Gas Project As we further expand Renergen’s current operations into Phase 2, we may face additional problems associated with natural gas exploration and development projects. Our ability to sustain or increase levels of helium and LNG production is dependent in part on the successful expansion of Renergen’

ASP Isotopes Completes Well Drilling Required for Phase 1 of Renergen Helium Project Four Months Ahead of

EXHIBIT 99.1 ASP Isotopes Completes Well Drilling Required for Phase 1 of Renergen Helium Project Four Months Ahead of Schedule DALLAS, March 23, 2026 (GLOBE NEWSWIRE) - ASP Isotopes Inc. (NASDAQ: ASPI) (“ASP Isotopes” or the “Company”), an advanced materials company focused on developing technologies and processes for the production of critical materials used in multiple industries, today announc

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): March 23, 2026

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): March 23, 2026 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission File N

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EXHIBIT 99.1 ASP Isotopes to Participate in Canaccord Genuity’s 2nd Annual CG Virtual Sustainability Summit Dallas, TX, March 10, 2026 - ASP Isotopes Inc. (NASDAQ: ASPI) (“ASP Isotopes” or the “Company”), an advanced materials company focused on developing technologies and processes for the production of critical materials used in multiple industries, today announced that Paul Mann, Chief Executiv

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): March 10, 2026

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): March 10, 2026 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission File N

Quantum Leap Energy Enters into Memorandum of Understanding with a Large U.S. Energy Company Regarding Evaluation of Support to Advance Domestic Enriched Uranium Fuel Supply Chain Marks an important step toward enhancing the domestic supply chain for

EXHIBIT 99.1 Quantum Leap Energy Enters into Memorandum of Understanding with a Large U.S. Energy Company Regarding Evaluation of Support to Advance Domestic Enriched Uranium Fuel Supply Chain Marks an important step toward enhancing the domestic supply chain for nuclear fuel in the United States Advances QLE’s strategy to build U.S.-based capabilities to support advanced nuclear fuel production D

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): March 6, 2026

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): March 6, 2026 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission File Nu

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): March 5, 2026

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): March 5, 2026 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission File Nu

Quantum Leap Energy Appoints Nate Salpeter, Ph.D., a Key Opinion Leader in Fluid Dynamics and Energy Technology, as its Chief Technology Officer Former TerraPower and Kairos Power engineer brings proven track record of scaling advanced energy technol

EXHIBIT 99.1 Quantum Leap Energy Appoints Nate Salpeter, Ph.D., a Key Opinion Leader in Fluid Dynamics and Energy Technology, as its Chief Technology Officer Former TerraPower and Kairos Power engineer brings proven track record of scaling advanced energy technologies DALLAS, March 5, 2026 - ASP Isotopes Inc. (NASDAQ: ASPI) (“ASPI”) today announced that Quantum Leap Energy LLC (“QLE” or the “Compa

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): February 23, 2026

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): February 23, 2026 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission Fil

ASP Isotopes Announces Quantum Leap Energy and Necsa Advance Strategic Collaboration Aimed at Production of HALEU Nuclear Fuel Agreement between QLE’s South African subsidiary and Necsa related to the siting, design, construction, commission and oper

EXHIBIT 99.1 ASP Isotopes Announces Quantum Leap Energy and Necsa Advance Strategic Collaboration Aimed at Production of HALEU Nuclear Fuel Agreement between QLE’s South African subsidiary and Necsa related to the siting, design, construction, commission and operation of an enrichment facility on the Necsa site in Pelindaba, with QLE’s objective to achieve market readiness for production of nuclea

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): February 19, 2026

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): February 19, 2026 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission Fil

ASP Isotopes Announces Establishment of Quantum Leap Energy Strategic Advisory Board, Bolstering its Plans for the Nuclear Fuel Sector Distinguished Nuclear Fuel and Advanced Materials Leaders Appointed as Initial SAB Members

EXHIBIT 99.1 ASP Isotopes Announces Establishment of Quantum Leap Energy Strategic Advisory Board, Bolstering its Plans for the Nuclear Fuel Sector Distinguished Nuclear Fuel and Advanced Materials Leaders Appointed as Initial SAB Members DALLAS, TX, February 19, 2026 - ASP Isotopes Inc. (NASDAQ: ASPI) (“ASPI”) today announced that Quantum Leap Energy LLC (“QLE” or the “Company”), a wholly-owned s

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): February 17, 2026

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): February 17, 2026 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission Fil

ASP Isotopes Announces Quantum Leap Energy to Establish Global Headquarters in Austin, TX State’s Support of Nuclear Power and Constructive Regulatory Environment to Boost Commercial Pathway for Developer of Advanced Nuclear Fuels

EXHIBIT 99.1 ASP Isotopes Announces Quantum Leap Energy to Establish Global Headquarters in Austin, TX State’s Support of Nuclear Power and Constructive Regulatory Environment to Boost Commercial Pathway for Developer of Advanced Nuclear Fuels Dallas, TX, February 17, 2026 - ASP Isotopes Inc. (NASDAQ: ASPI) (“ASPI”) today announced its plans for Quantum Leap Energy LLC (“QLE” or the “Company”), a

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): January 26, 2026

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): January 26, 2026 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission File

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): January 29, 2026

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): January 29, 2026 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission File

ASP Isotopes Inc. Provides Production Update on the Renergen Helium Project

EXHIBIT 99.1 ASP Isotopes Inc. Provides Production Update on the Renergen Helium Project This Production Update reports operational progress since April 2025, following bridge loan funding provided by ASP Isotopes Inc. (“ASPI”) (prior to the completion of ASPI’s acquisition of Renergen), and highlights measurable improvements in drilling execution, gas production, subsurface confidence, and commer

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): January 6, 2026

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): January 6, 2026 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission File

ASP Isotopes Closes Acquisition of Renergen Combined Company Expected to Become a Global Critical Materials Provider Focused on High-Growth Industries in Isotope and Helium Markets Renergen Expected to Benefit from $750 million of Committed Debt Fund

EXHIBIT 99.2 ASP Isotopes Closes Acquisition of Renergen Combined Company Expected to Become a Global Critical Materials Provider Focused on High-Growth Industries in Isotope and Helium Markets Renergen Expected to Benefit from $750 million of Committed Debt Funding from the U.S. government's Development Finance Corporation (U.S. DFC) and Other Lenders to Expand Helium Plant Production Capacity Co

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): January 6, 2026

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): January 6, 2026 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission File

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): December 18, 2025

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): December 18, 2025 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission Fil

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): December 18, 2025

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): December 18, 2025 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission Fil

ASP Isotopes Inc. Announces Receipt of Regulatory Approvals for Acquisition of Renergen Limited

EXHIBIT 99.1 ASP Isotopes Inc. Announces Receipt of Regulatory Approvals for Acquisition of Renergen Limited Positive progress in operations at Renergen’s Virginia Gas Project with a production update expected at the end of January 2026 Washington, D.C., December 17, 2025 (GLOBE NEWSWIRE) - ASP Isotopes Inc. NASDAQ: ASPI ("ASP Isotopes” or the “Company”), an advanced materials company dedicated to

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): December 17, 2025

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): December 17, 2025 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission Fil

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): December 2, 2025

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): December 2, 2025 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission File

ASP Isotopes Inc. Announces Paul Mann to Return from Temporary Leave of Absence as Executive Chairman and Chief Executive Officer

EXHIBIT 99.1 ASP Isotopes Inc. Announces Paul Mann to Return from Temporary Leave of Absence as Executive Chairman and Chief Executive Officer Washington, D.C., December 2, 2025 (GLOBE NEWSWIRE) - ASP Isotopes Inc. NASDAQ: ASPI ("ASP Isotopes” or the “Company”), an advanced materials company dedicated to the development of technology and processes for the production of isotopes for use in multiple

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): December 2, 2025

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): December 2, 2025 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission File

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): November 27, 2025

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): November 27, 2025 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission Fil

[SINGATURE PAGE FOLLOWS]

EXHIBIT 10.1 27 November 2025 To: ASP Isotopes Inc. 601 Pennsylvania Avenue NW, South Building, Suite 900 Washington, DC; and ASP Isotopes South Africa Proprietary Limited Unit 19, 2nd Floor 1 Melrose Boulevard Johannesburg 2196 From: Renergen Limited Sandton Gate, Second Floor, 25 Minerva Avenue, Glenadrienne, Sandton, Gauteng, 2196 Attn: Robert Ainscow/Paul E. Mann LETTER TO THE TERM LOAN FACILI

The Board of Directors, Renergen Limited.

EXHIBIT 2.1 ASP Isotopes Inc. (NASDAQ: ASPI) Executives: P Mann (CEO), RD Ainscow (COO), H Kiessling (CFO) Non-executive Directors: D Moore, T Wider, M Gorley, R Ryan Address: 601 Pennsylvania Avenue NW, South Building, Suite 900 Washington, DC 20004 www.ASPlsotopes.com To: The Board of Directors, Renergen Limited. Date: 27 November 2025 RE: AGREEMENT TO EXTEND FULFILMENT DATE FOR THE PROPOSED TRA

RENERGEN LIMITED (Incorporated in the Republic of South Africa) (Registration number 2014/195093/06) JSE and A2X Share code: REN ISIN: ZAE000202610 Australian Business Number (ABN): 93 998 352 675 ASX Share code: RLT

EXHIBIT 99.1 RENERGEN LIMITED (Incorporated in the Republic of South Africa) (Registration number 2014/195093/06) JSE and A2X Share code: REN ISIN: ZAE000202610 LEI:378900B1512179F35A69 Australian Business Number (ABN): 93 998 352 675 ASX Share code: RLT (“Renergen”) ASP ISOTOPES INC. (Incorporated in the State of Delaware, United States of America) (Delaware file number 6228898) Ticker Symbol: NA

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Filed by the Registrant ☒ Filed by a party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ☒ Definitive Proxy State

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): November 21, 2025

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): November 21, 2025 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission Fil

THIRD QUARTER UPDATE

EXHIBIT 99.1

Voting Agreement, dated as of July 28, 2025, by and among IsoBio, Inc., ASP Isotopes Inc. and the Key Holders named therein

Exhibit 10.3 Execution Version VOTING AGREEMENT THIS VOTING AGREEMENT (this “Agreement”) is made as of July 24, 2025, by and among IsoBio, Inc., a Delaware corporation (the “Company”), the Investors (as defined below), the Key Holders (as defined below), and other Stockholders (as defined below). RECITALS WHEREAS, the Company and the Investors are parties to that certain Series Seed-1 Preferred St

Right of First Refusal and Co-Sale Agreement, dated as of July 28, 2025, by and among IsoBio, Inc. ASP Isotopes Inc. and the Key Holders named therein

Exhibit 10.4 Execution Version RIGHT OF FIRST REFUSAL AND CO-SALE AGREEMENT THIS RIGHT OF FIRST REFUSAL AND CO-SALE AGREEMENT (this “Agreement”), is made as of July 24, 2025, by and among IsoBio, Inc., a Delaware corporation (the “Company”), the Investors (as defined below) and the Key Holders (as defined below). RECITALS WHEREAS, each Key Holder is the beneficial owner of shares of Capital Stock,

Investors’ Rights Agreement, dated as of July 28, 2025, by and among IsoBio, Inc. and the Investors named therein

Exhibit 10.2 Execution Version INVESTORS’ RIGHTS AGREEMENT THIS INVESTORS’ RIGHTS AGREEMENT (this “Agreement”), is made as of July 24, 2025, by and among IsoBio, Inc., a Delaware corporation (the “Company”) and the Investors (as defined below). RECITALS WHEREAS, the Company and the Investors are parties to that certain Series Seed-1 Preferred Stock Purchase Agreement of even date herewith by and a

Letter, dated as of November 6, 2025, to the Term Loan Facility Agreement by and among ASP Isotopes Inc., Renergen Limited and ASP Isotopes South Africa Proprietary Limited

Exhibit 10.5 [Renergen Letterhead] 6 November 2025 To: ASP Isotopes Inc. 601 Pennsylvania Avenue NW, South Building, Suite 900 Washington, DC; and ASP Isotopes South Africa Proprietary Limited Unit 19, 2nd Floor 1 Melrose Boulevard Johannesburg 2196 From: Renergen Limited Sandton Gate, Second Floor, 25 Minerva Avenue, Glenadrienne, Sandton, Gauteng, 2196 Attn: Robert Ainscow/Paul E. Mann LETTER TO

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q (Mark One)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2025 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-41555 ASP Isotopes Inc.

Series Seed-1 Preferred Stock Purchase Agreement, dated as of July 28, 2025, by and between IsoBio, Inc. and ASP Isotopes Inc.

Exhibit 10.1 Execution Version SERIES SEED-1 PREFERRED STOCK PURCHASE AGREEMENT THIS SERIES SEED-1 PREFERRED STOCK PURCHASE AGREEMENT (this “Agreement”), is made as of July 28, 2025, by and among IsoBio, Inc., a Delaware corporation (the “Company”), and ASP Isotopes Inc., a Delaware corporation (the “Purchaser”). The parties hereby agree as follows: 1. Purchase and Sale of Preferred Stock. 1.1 Sal

ASP Isotopes to Provide Quarterly Business Update Call on November 21, 2025 at 8:30am EST

EXHIBIT 99.1 ASP Isotopes to Provide Quarterly Business Update Call on November 21, 2025 at 8:30am EST Washington, D.C., November 17, 2025 (GLOBE NEWSWIRE) - ASP Isotopes Inc. (NASDAQ: ASPI) (“ASP Isotopes” or the “Company”), an advanced materials company focused on developing technologies and processes for the production of isotopes for multiple industries, today announced it will hold a quarterl

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): November 17, 2025

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): November 17, 2025 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission Fil

FORM OF CONVERTIBLE NOTE PURCHASE AGREEMENT

EXHIBIT 10.1 FORM OF CONVERTIBLE NOTE PURCHASE AGREEMENT This Convertible Note Purchase Agreement (this “Agreement”), dated as of November , 2025, is entered into among Quantum Leap Energy LLC, a Delaware limited liability company (the “Company”), and the persons and entities (each individually a “Purchaser,” and collectively, the “Purchasers”) named on the Schedule of Purchasers attached hereto (

FORM OF REGISTRATION RIGHTS AGREEMENT

EXHIBIT 10.2 FORM OF REGISTRATION RIGHTS AGREEMENT This Registration Rights Agreement (this “Agreement”) is made and entered into as of November , 2025 among Quantum Leap Energy LLC, a Delaware limited liability company (the “Company”), and the persons identified on Schedule A hereto (collectively, the “Investors” and, each individually, an “Investor”). WHEREAS, the Company and the Investors liste

OMB APPROVAL

OMB APPROVAL OMB Number: 3235-0058 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Expires: September 30, 2028 Estimated average burden Washington, D.

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): November 7, 2025

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): November 7, 2025 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission File

ASP Isotopes Announces Quantum Leap Energy’s Confidential Submission of Draft Registration Statement for Proposed Initial Public Offering

EXHIBIT 99.1 ASP Isotopes Announces Quantum Leap Energy’s Confidential Submission of Draft Registration Statement for Proposed Initial Public Offering WASHINGTON, Nov. 12, 2025 (GLOBE NEWSWIRE) - ASP Isotopes Inc. (NASDAQ: ASPI) today announced that its wholly-owned subsidiary, Quantum Leap Energy LLC (“QLE”), has confidentially submitted a draft registration statement on Form S-1 to the Securitie

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): November 12, 2025

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): November 12, 2025 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission Fil

CORPORATE OVERVIEW

EXHIBIT 99.1

Quantum Leap Energy LLC Announces Private Placement of Convertible Notes Led by American Ventures LLC

EXHIBIT 99.2 Quantum Leap Energy LLC Announces Private Placement of Convertible Notes Led by American Ventures LLC WASHINGTON, Nov. 7, 2025 (GLOBE NEWSWIRE) – Quantum Leap Energy LLC (“QLE”), a wholly-owned subsidiary of ASP Isotopes Inc. NASDAQ: ASPI (“ASP Isotopes” or “ASPI” or the “Company”), an advanced materials company focused on developing technologies and processes for the production of is

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): November 7, 2025

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): November 7, 2025 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission File

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): November 5, 2025

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): November 5, 2025 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission File

ASP Isotopes’ UK Subsidiary, Quantum Leap Energy Ltd., Enters Early Engagement Process with UK Nuclear Regulators Rich Deakin joins QLE Ltd as Senior Vice President and Managing Director UK Strategic Projects, bringing significant nuclear industry ex

EXHIBIT 99.1 ASP Isotopes’ UK Subsidiary, Quantum Leap Energy Ltd., Enters Early Engagement Process with UK Nuclear Regulators Rich Deakin joins QLE Ltd as Senior Vice President and Managing Director UK Strategic Projects, bringing significant nuclear industry experience Washington, D.C., November 5, 2025 (GLOBE NEWSWIRE) - ASP Isotopes Inc. (NASDAQ: ASPI) (“ASP Isotopes” or the “Company”), an adv

Quantum Leap Energy LLC Completes the Acquisition of One 30 Seven Inc. Assets to Advance Solutions for the Processing of Water-Soluble Nuclear Waste

EXHIBIT 99.1 Quantum Leap Energy LLC Completes the Acquisition of One 30 Seven Inc. Assets to Advance Solutions for the Processing of Water-Soluble Nuclear Waste - Quantum Leap Energy LLC plans to utilize technology acquired from One 30 Seven to develop Creber Units to process water-soluble nuclear waste by accelerating beta decay of radioactive waste, such as Cesium-137 and Strontium-90. - There

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): October 23, 2025

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): October 23, 2025 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission File

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): October 14, 2025

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): October 14, 2025 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission File

ASP Isotopes Inc. Announces Proposed Public Offering of Common Stock

EXHIBIT 99.1 ASP Isotopes Inc. Announces Proposed Public Offering of Common Stock Washington, D.C., October 14, 2025 (GLOBE NEWSWIRE) - ASP Isotopes Inc. NASDAQ: ASPI ("ASP Isotopes” or the “Company”), an advanced materials company dedicated to the development of technology and processes for the production of isotopes for use in multiple industries, today announced that it is commencing an underwr

17,167,380 Shares ASP Isotopes Inc. Common Stock UNDERWRITING AGREEMENT

EXHIBIT 1.1 17,167,380 Shares ASP Isotopes Inc. Common Stock UNDERWRITING AGREEMENT October 15, 2025 Cantor Fitzgerald & Co. Lucid Capital Markets, LLC As Representatives of the Several Underwriters named in Schedule I attached hereto 570 Lexington Avenue, 40th Floor New York, NY 10022 Ladies and Gentlemen: ASP Isotopes Inc., a Delaware corporation (the “Company”), proposes to sell 17,167,380 shar

$210,300,405 of Shares of Common Stock

Filed Pursuant to Rule 424(b)(5) File No. 333-290864 Prospectus Supplement (To Prospectus dated October 14, 2025) $210,300,405 of Shares of Common Stock We are offering shares of our common stock, par value $0.01 per share, having an aggregate indicative offering price of $210,300,405, pursuant to this prospectus supplement and the accompanying prospectus. Our common stock is currently traded on t

ASP Isotopes Inc. Announces Pricing of Public Offering of Common Stock

EXHIBIT 99.2 ASP Isotopes Inc. Announces Pricing of Public Offering of Common Stock Washington, D.C., October 15, 2025 (GLOBE NEWSWIRE) - ASP Isotopes Inc. NASDAQ: ASPI ("ASP Isotopes” or the “Company”), an advanced materials company dedicated to the development of technology and processes for the production of isotopes for use in multiple industries, today announced the pricing of an underwritten

SUBJECT TO COMPLETION, DATED OCTOBER 14, 2025

The information in this preliminary prospectus supplement is not complete and may be changed.

Calculation of Filing Fee Tables Form S-3ASR (Form Type) ASP Isotopes Inc. (Exact Name of Registrant as Specified in its Charter) Table 1: Newly Registered and Carry Forward Securities

EXHIBIT 107 Calculation of Filing Fee Tables Form S-3ASR (Form Type) ASP Isotopes Inc.

ASP ISOTOPES INC. DATED AS OF , 20 SENIOR DEBT SECURITIES TABLE OF CONTENTS

EXHIBIT 4.1 ASP ISOTOPES INC. ISSUER AND [TRUSTEE], TRUSTEE INDENTURE DATED AS OF , 20 SENIOR DEBT SECURITIES TABLE OF CONTENTS Page ARTICLE One. - DEFINITIONS AND OTHER PROVISIONS OF GENERAL APPLICATION 2 SECTION 101. Definitions 2 SECTION 102. Compliance Certificates and Opinions 11 SECTION 103. Form of Documents Delivered to Trustee 12 SECTION 104. Acts of Holders 12 SECTION 105. Notices, etc.,

ASP ISOTOPES INC. DATED AS OF , 20 SUBORDINATED DEBT SECURITIES TABLE OF CONTENTS

EXHIBIT 4.2 ASP ISOTOPES INC. ISSUER AND [TRUSTEE], TRUSTEE INDENTURE DATED AS OF , 20 SUBORDINATED DEBT SECURITIES TABLE OF CONTENTS Page ARTICLE ONE. - DEFINITIONS AND OTHER PROVISIONS OF GENERAL APPLICATION 2 Section 101. Definitions 2 Section 102. Compliance Certificates and Opinions 11 Section 103. Form of Documents Delivered to Trustee 12 Section 104. Acts of Holders 12 Section 105. Notices,

ASP Isotopes Provides Business Updates

EXHIBIT 99.1 ASP Isotopes Provides Business Updates Washington, D.C., October 13, 2025 (GLOBE NEWSWIRE) - ASP Isotopes Inc. NASDAQ: ASPI ("ASP Isotopes” or the “Company”), an advanced materials company dedicated to the development of technology and processes for the production of isotopes for use in multiple industries, today provided a business development update, including a supply agreement for

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): October 13, 2025

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): October 13, 2025 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission File

As filed with the Securities and Exchange Commission on October 14, 2025

As filed with the Securities and Exchange Commission on October 14, 2025 Registration No.

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 29, 2025

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 29, 2025 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission Fi

144

144 0002012446 XXXXXXXX LIVE 0001921865 ASP Isotopes Inc. 001-41555 601 Pennsylvania Avenue NW South Building, Suite 900 Washington DC 20004 2027562245 Gorley Michael DIRECTOR Common Stock Independent Trading Group (ITG) Inc. 33 Yonge Street Suite 420 Toronto AK ON M5E 1G4 64000 662400 91913109 09/30/2025 NASDAQ Common Stock 10/23/2023 Acquired as compensation - Restricted Stock Award Issuer N 934

ASP Isotopes Announces Purchase Order for Enriched Barium-137 from a U.S.-Based Customer

EXHIBIT 99.1 ASP Isotopes Announces Purchase Order for Enriched Barium-137 from a U.S.-Based Customer Washington, D.C., September 30, 2025 (GLOBE NEWSWIRE) - ASP Isotopes Inc. NASDAQ: ASPI ("ASP Isotopes” or the “Company”), an advanced materials company dedicated to the development of technology and processes for the production of isotopes for use in multiple industries, today announced that it ha

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 30, 2025

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 30, 2025 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission Fi

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 29, 2025

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 29, 2025 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission Fi

ASP Isotopes Inc. Announces Changes to the Executive Management Teams of ASP Isotopes Inc. and Quantum Leap Energy LLC Effective October 2025

EXHIBIT 99.1 ASP Isotopes Inc. Announces Changes to the Executive Management Teams of ASP Isotopes Inc. and Quantum Leap Energy LLC Effective October 2025 - ASP Isotopes Inc. appoints Interim CEO as Paul Mann becomes Executive Chairman. - Quantum Leap Energy LLC appoints Michael Cunniffe as CFO. - ASP Isotopes Inc. provides information on upcoming investor events. Washington, D.C., September 29, 2

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): August 29, 2025

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): August 29, 2025 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission File

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

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 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission Fi

144

144 0001642715 XXXXXXXX LIVE 0001921865 ASP Isotopes, Inc. 001-41555 601 Pennsylvania Avenue NW, South Building, Suite 900 Washington DC 20004 2027562245 Todd Wider Director Common J.P. Morgan Securities LLC 390 Madison Avenue 6th Floor New York NY 10017 75000 657750 91913109 09/12/2025 Nasdaq Common 11/15/2024 Compensation Issuer N 75000 11/15/2024 NA Y 09/12/2025 /s/ J.P. Morgan Securities LLC a

144

144 0001951275 XXXXXXXX LIVE 0001921865 ASP Isotopes Inc. 001-41555 601 PENNSYLVANIA AVENUE NW SOUTH BUILDING, SUITE 900 WASHINGTON DC 20004 202-756-2245 Ainscow Robert Officer Common Stock Independent Trading Group (ITG) Inc. 33 Yonge Street Suite 420 Toronto A6 M5E 1G4 8438 69191.60 91913109 09/08/2025 NASDAQ Common Stock 09/06/2024 Acquired as compensation - Restricted Stock Award Issuer N 3000

144

144 0001744816 XXXXXXXX LIVE 0001921865 ASP Isotopes Inc. 001-41555 601 PENNSYLVANIA AVENUE NW SOUTH BUILDING, SUITE 900 WASHINGTON DC 20004 202-756-2245 Mann Paul Elliot Officer Director 10% Stockholder Common Stock Independent Trading Group (ITG) Inc. 33 Yonge Street Suite 420 Toronto A6 M5E 1G4 8438 69191.60 91913109 09/08/2025 NASDAQ Common Stock 09/06/2024 Acquired as compensation - Restricte

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 6, 2025

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 6, 2025 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission Fil

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 2, 2025

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 2, 2025 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission Fil

ASP Isotopes Issues Letter to Shareholders

EXHIBIT 99.1 ASP Isotopes Issues Letter to Shareholders Washington, D.C., September 2, 2025 (GLOBE NEWSWIRE) - ASP Isotopes Inc. (NASDAQ: ASPI) ("ASP Isotopes” or the “Company”), an advanced materials company dedicated to the development of technology and processes for the production of isotopes for use in multiple industries, today released the following letter to shareholders from its Chairman a

144

144 0001888265 XXXXXXXX LIVE 0001921865 ASP Isotopes Inc. 001-41555 601 PENNSYLVANIA AVENUE NW SOUTH BUILDING, SUITE 900 WASHINGTON DC 20004 202-756-2245 Moore Duncan Director Common Stock Independent Trading Group (ITG) Inc. 33 Yonge Street, Suite 420 Toronto A6 M5E 1G4 75000 789750.00 91913109 08/29/2025 NASDAQ Common Stock 08/16/2023 Acquired as compensation - Restricted Stock Award Issuer N 20

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): August 25, 2025

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): August 25, 2025 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission File

ASP Isotopes Inc. and its Subsidiary, Quantum Leap Energy LLC, enter into a Memorandum of Understanding with Fermi America Regarding a Joint Venture to Collaborate on the Research, Development and Construction of an Advanced Nuclear Fuel Research and

EXHIBIT 99.1 ASP Isotopes Inc. and its Subsidiary, Quantum Leap Energy LLC, enter into a Memorandum of Understanding with Fermi America Regarding a Joint Venture to Collaborate on the Research, Development and Construction of an Advanced Nuclear Fuel Research and Production Facility at the Planned 11GW HyperGrid Campus in Carson County, Texas - Fermi America is a private U.S. developer of the plan

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): August 15, 2025

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): August 15, 2025 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission File

Natrium Project Procurement Terms and Conditions – Enrichment Services by and between TerraPower, LLC and ASP Isotopes Inc., dated as of May 16, 2025

Exhibit 10.3 NATRIUM PROJECT PROCUREMENT TERMS AND CONDITIONS – ENRICHMENT SERVICES BY AND BETWEEN TERRAPOWER, llc AND ASP ISOTOPES INC. DATED AS OF MAY 16, 2025 Exhibit 10.3 TABLE OF CONTENTS 1. Definitions. 1 2. Work Authorization - Purchase Order. 6 2.1. Issuance of Purchase Order. 6 2.2. Base Line Item. 6 2.3. [Reserved]. 6 2.4. Price Basis. 6 3. Performance of the Work. 6 3.1. Statement of Wo

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q (Mark One)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2025 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-41555 ASP Isotopes Inc.

HALEU Long-Term Supply Agreement by and between TerraPower, LLC and ASP Isotopes Inc., dated as of May 16, 2025

Exhibit 10.4 HALEU LONG-TERM SUPPLY AGREEMENT BY AND BETWEEN TERRAPOWER, llc AND ASP ISOTOPES INC. DATED AS OF MAY 16, 2025 Exhibit 10.4 TABLE OF CONTENTS 1. Definitions. 1 2. Work Authorization - Purchase Order. 7 2.1. Issuance of Purchase Order. 7 2.2. Base Line Item. 7 2.3. [Reserved]. 7 2.4. Price; Price Basis. 7 2.5. Quantity; Delivery Quantity Annual Estimate; Committed Quantity. 7 2.6. Addi

ASP Isotopes Inc. 2025 Inducement Equity Incentive Plan and forms of award agreement thereunder.

Exhibit 10.1 ASP ISOTOPES INC. 2025 INDUCEMENT EQUITY INCENTIVE PLAN Exhibit 10.1 TABLE OF CONTENTS ASP Isotopes Inc. 2025 Inducement Equity Incentive Plan 1 1. Establishment, Purpose and term of Plan. 1 1.1 Establishment 1 1.2 Purpose 1 1.3 Term of Plan 1 2. Definitions and Construction. 1 2.1 Definitions 1 2.2 Construction 8 3. Administration. 9 3.1 Administration by the Committee 9 3.2 Authorit

ASP Isotopes Inc. Announces Expected Commencement of Dual Listing on Johannesburg Stock Exchange

EXHIBIT 99.1 ASP Isotopes Inc. Announces Expected Commencement of Dual Listing on Johannesburg Stock Exchange Washington, D.C., August 8, 2025 (GLOBE NEWSWIRE) - ASP Isotopes Inc. NASDAQ: ASPI ("ASP Isotopes” or the “Company”), an advanced materials company dedicated to the development of technology and processes for the production of isotopes for use in multiple industries, today provided an upda

Financial Statements and Exhibits, Other Events

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): August 8, 2025 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission File N

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form CB TENDER OFFER/RIGHTS OFFERING NOTIFICATION FORM (AMENDMENT NO. 4)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form CB TENDER OFFER/RIGHTS OFFERING NOTIFICATION FORM (AMENDMENT NO. 4) Please place an X in the box(es) to designate the appropriate rule provision(s) relied upon to file this Form: Securities Act Rule 801 (Rights Offering) ☐ Securities Act Rule 802 (Exchange Offer) ☒ Exchange Act Rule 13e-4(h)(8) (Issuer Tender Offer) ☐ Exc

Abridged Pre-listing Statement released by ASP Isotopes Inc. on the Stock Exchange News Service of the JSE Limited on August 8, 2025 for the purposes of complying with the JSE Listings Requirements in connection with the listing of ASP Isotopes Inc. shares of common stock on the Main Board of the Johannesburg Stock Exchange.

EXHIBIT 99.5 ASP ISOTOPES INC. (Incorporated in the State of Delaware, United States of America) (Delaware file number 6228898) Ticker Symbol: NASDAQ: ASPI ISIN: US00218A1051 LEI: 6488WHV94BZ496OZ3219 JSE Share Code: ISO ("ASPI" or "the Company") SECONDARY LISTING OF ASPI ON THE MAIN BOARD OF THE JSE LIMITED ("JSE") AND ABRIDGED PRE-LISTING STATEMENT Unless otherwise stated, capitalised terms used

Investor presentation regarding IsoBio dated July 2025.

EXHIBIT 99.1

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): July 28, 2025

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): July 28, 2025 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission File Nu

ASP Isotopes Inc. and IsoBio, Inc. Announce Series Seed Funding of IsoBio, Inc. to Advance Innovative Antibody-Isotope Conjugates (AICsTM) For Cancer Treatment

EXHIBIT 99.1 ASP Isotopes Inc. and IsoBio, Inc. Announce Series Seed Funding of IsoBio, Inc. to Advance Innovative Antibody-Isotope Conjugates (AICsTM) For Cancer Treatment - IsoBio, Inc. (IsoBio) is a U.S.-based radiotherapeutic development company focused on developing a broad pipeline of mAb-based radioisotope therapeutics, known as antibody-isotope conjugates (AICsTM), targeting both derisked

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): July 28, 2025

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): July 28, 2025 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission File Nu

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): July 25, 2025

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): July 25, 2025 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission File Nu

Competition Commission of South Africa Approves the Offer by ASP Isotopes Inc. for Renergen Limited

EXHIBIT 99.1 Competition Commission of South Africa Approves the Offer by ASP Isotopes Inc. for Renergen Limited Washington, D.C., July 25, 2025 (GLOBE NEWSWIRE) - ASP Isotopes Inc. NASDAQ: ASPI ("ASP Isotopes” or the “Company”), an advanced materials company dedicated to the development of technology and processes for the production of isotopes for use in multiple industries, today announced that

Underwriting Agreement, dated as of July 23, 2025, by and between the Company and Cantor Fitzgerald & Co. as representative of the several underwriters named therein.

EXHIBIT 1.1 7,500,000 Shares ASP Isotopes Inc. Common Stock UNDERWRITING AGREEMENT July 23, 2025 Cantor Fitzgerald & Co. As Representative of the Several Underwriters named in Schedule I attached hereto 499 Park Avenue New York, New York 10022 Ladies and Gentlemen: ASP Isotopes Inc., a Delaware corporation (the “Company”), proposes to sell 7,500,000 shares (the “Stock”) of the Company’s common sto

7,500,000 Shares Common Stock

Filed Pursuant to Rule 424(b)(5) File No. 333-286860 File No. 333-288894 PROSPECTUS SUPPLEMENT (to Prospectus dated May 30, 2025) 7,500,000 Shares Common Stock We are offering 7,500,000 shares of our common stock, par value $0.01 per share, at an offering price of $8.00 per share. Our common stock is listed on The Nasdaq Capital Market, or “Nasdaq,” under the symbol “ASPI.” On July 23, 2025, the l

ASP Isotopes Inc. Announces Pricing of $60 Million Underwritten Registered Direct Offering of Common Stock

EXHIBIT 99.1 ASP Isotopes Inc. Announces Pricing of $60 Million Underwritten Registered Direct Offering of Common Stock Washington, D.C., July 23, 2025 (GLOBE NEWSWIRE) - ASP Isotopes Inc. NASDAQ: ASPI ("ASP Isotopes” or the “Company”), today announced the pricing of an underwritten registered direct offering of 7,500,000 shares of its common stock at a price of $8.00 per share to a single fundame

7,500,000 Shares Common Stock

Filed Pursuant to Rule 424(b)(5) File No. 333-286860 File No. 333-288894 PROSPECTUS SUPPLEMENT (to Prospectus dated May 30, 2025) 7,500,000 Shares Common Stock We are offering 7,500,000 shares of our common stock, par value $0.01 per share, at an offering price of $8.00 per share. Our common stock is listed on The Nasdaq Capital Market, or “Nasdaq,” under the symbol “ASPI.” On July 23, 2025, the l

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): July 23, 2025

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): July 23, 2025 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission File Nu

As filed with the Securities and Exchange Commission on July 23, 2025

As filed with the Securities and Exchange Commission on July 23, 2025 Registration No.

Filing Fee Table.

EXHIBIT 107 EX-FILING FEES Calculation of Filing Fee Tables Form S-3 (Form Type) ASP Isotopes Inc.

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): July 17, 2025

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): July 17, 2025 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission File Nu

ASP Isotopes Inc. Announces Updates on the Progress of Commercial Production at its Three Enrichment Facilities in South Africa.

EXHIBIT 99.1 ASP Isotopes Inc. Announces Updates on the Progress of Commercial Production at its Three Enrichment Facilities in South Africa. Washington, D.C., July 17, 2025 (GLOBE NEWSWIRE) - ASP Isotopes Inc. NASDAQ: ASPI ("ASP Isotopes” or the “Company”), an advanced materials company dedicated to the development of technology and processes for the production of isotopes for use in multiple ind

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): July 11, 2025

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): July 11, 2025 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission File Nu

Shareholders of Renergen Limited Approve Proposed Acquisition by ASP Isotopes Inc.

EXHIBIT 99.1 Shareholders of Renergen Limited Approve Proposed Acquisition by ASP Isotopes Inc. Washington, D.C., July 11, 2025 (GLOBE NEWSWIRE) - ASP Isotopes Inc. NASDAQ: ASPI (“ASP Isotopes” or the “Company”), an advanced materials company dedicated to the development of technology and processes for the production of isotopes for use in multiple industries, today announced that at a general mee

Joint Announcement released by Renergen and ASP Isotopes Inc. on the Stock Exchange News Service of the JSE Limited on June 12, 2025 regarding Distribution of Circular, Notice of General Meeting and Withdrawal of Cautionary Announcement.

EXHIBIT 99.8 RENERGEN LIMITED (Incorporated in the Republic of South Africa) (Registration number 2014/195093/06) JSE and A2X Share code: REN ISIN: ZAE000202610 LEI:378900B1512179F35A69 Australian Business Number (ABN): 93 998 352 675 ASX Share code: RLT (“Renergen”) ASP ISOTOPES INC. (Incorporated in the State of Delaware, United States of America) (Delaware file number 6228898) Ticker Symbol: NA

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form CB TENDER OFFER/RIGHTS OFFERING NOTIFICATION FORM (AMENDMENT NO. 3)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form CB TENDER OFFER/RIGHTS OFFERING NOTIFICATION FORM (AMENDMENT NO. 3) Please place an X in the box(es) to designate the appropriate rule provision(s) relied upon to file this Form: Securities Act Rule 801 (Rights Offering) ☐ Securities Act Rule 802 (Exchange Offer) ☒ Exchange Act Rule 13e-4(h)(8) (Issuer Tender Offer) ☐ Exc

Combined Circular to Renergen Shareholders in Relation to Scheme of Arrangement and Standby Offer

EXHIBIT 99.1

ASP Isotopes Inc. Enhances the Quantum Leap Energy LLC (QLE) Executive Leadership Team with the Appointment of Ryno Pretorius as Chief Executive Officer of QLE

EXHIBIT 99.1 ASP Isotopes Inc. Enhances the Quantum Leap Energy LLC (QLE) Executive Leadership Team with the Appointment of Ryno Pretorius as Chief Executive Officer of QLE Washington, D.C., June 11, 2025 (GLOBE NEWSWIRE) - ASP Isotopes Inc. NASDAQ: ASPI ("ASP Isotopes” or the “Company”), an advanced materials company dedicated to the development of technology and processes for the production of i

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): June 11, 2025

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): June 11, 2025 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission File Nu

ASP Isotopes Inc. to host Investor Access Event in South Africa from June 16-18, 2025

EXHIBIT 99.2 ASP Isotopes Inc. to host Investor Access Event in South Africa from June 16-18, 2025 Washington, D.C., June 4, 2025 (GLOBE NEWSWIRE) - ASP Isotopes Inc. NASDAQ: ASPI ("ASP Isotopes” or the “Company”), an advanced materials company dedicated to the development of technology and processes for the production of isotopes for use in multiple industries, today announced that it will host a

ASP Isotopes and Isotopia Announce Supply Agreement for Gadolinium-160 to Accelerate Terbium-161 Production for Advanced Cancer Therapies

EXHIBIT 99.1 ASP Isotopes and Isotopia Announce Supply Agreement for Gadolinium-160 to Accelerate Terbium-161 Production for Advanced Cancer Therapies - Gadolinium-160 is a critical precursor isotope for producing Terbium-161, an emerging medical isotope with significant potential in targeted radiotherapies. - Supply agreement is for four years’ supply of enriched Gd-160, commencing in 2026, with

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): June 4, 2025

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): June 4, 2025 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission File Num

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): June 2, 2025

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): June 2, 2025 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission File Num

7,518,797 Shares Common Stock

Filed Pursuant to Rule 424(b)(5) File No. 333-286860 PROSPECTUS SUPPLEMENT (to Prospectus dated May 30, 2025) 7,518,797 Shares 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 last reported sale pri

Underwriting Agreement, dated as of June 2, 2025, by and between the Company and Cantor Fitzgerald & Co. as representative of the several underwriters named therein.

EXHIBIT 1.1 7,518,797 Shares ASP Isotopes Inc. Common Stock UNDERWRITING AGREEMENT June 2, 2025 Cantor Fitzgerald & Co. As Representative of the Several Underwriters named in Schedule I attached hereto 499 Park Avenue New York, New York 10022 Ladies and Gentlemen: ASP Isotopes Inc., a Delaware corporation (the “Company”), proposes to sell 7,518,797 shares (the “Stock”) of the Company’s common stoc

ASP Isotopes Inc. Announces Pricing of $50 Million Underwritten Registered Direct Offering of Common Stock

EXHIBIT 99.1 ASP Isotopes Inc. Announces Pricing of $50 Million Underwritten Registered Direct Offering of Common Stock Washington, D.C., June 2, 2025 (GLOBE NEWSWIRE) - ASP Isotopes Inc. NASDAQ: ASPI ("ASP Isotopes” or the “Company”), today announced the pricing of an underwritten registered direct offering of 7,518,797 shares of its common stock at a price of $6.65 per share to a single fundamen

Circular to Renergen Shareholders in Relation to Shareholder Ratification Resolution

EXHIBIT 99.2 THIS CIRCULAR IS IMPORTANT AND REQUIRES YOUR IMMEDIATE ATTENTION The definitions and interpretations commencing on page 6 of this Circular apply, unless the context clearly indicates otherwise, throughout this Circular, including this cover page. Action required: 1. This entire Circular is important and should be read with particular attention to the section entitled “Action required

Regulation FD Disclosure, Financial Statements and Exhibits

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): May 29, 2025 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission File Num

ASP Isotopes Issues Letter to Shareholders.

EXHIBIT 99.1 ASP Isotopes Issues Letter to Shareholders. Washington, D.C., May 29, 2025 (GLOBE NEWSWIRE) - ASP Isotopes Inc. (NASDAQ: ASPI) ("ASP Isotopes” or the “Company”), an advanced materials company dedicated to the development of technology and processes for the production of isotopes for use in multiple industries, today released the following letter to shareholders from its Chairman and C

Announcement released by Renergen on the Stock Exchange News Service of the JSE Limited on May 28, 2025 regarding Distribution of Circular and Notice of General Meeting.

EXHIBIT 99.7 RENERGEN LIMITED (Incorporated in the Republic of South Africa) (Registration number 2014/195093/06) JSE and A2X Share code: REN ISIN: ZAE000202610 LEI:378900B1512179F35A69 Australian Business Number (ABN): 93 998 352 675 ASX Share code: RLT (“Renergen”) DISTRIBUTION OF CIRCULAR AND NOTICE OF GENERAL MEETING Unless expressly defined otherwise, capitalised terms herein have the same me

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form CB TENDER OFFER/RIGHTS OFFERING NOTIFICATION FORM (AMENDMENT NO. 2)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form CB TENDER OFFER/RIGHTS OFFERING NOTIFICATION FORM (AMENDMENT NO. 2) Please place an X in the box(es) to designate the appropriate rule provision(s) relied upon to file this Form: Securities Act Rule 801 (Rights Offering) ☐ Securities Act Rule 802 (Exchange Offer) ☒ Exchange Act Rule 13e-4(h)(8) (Issuer Tender Offer) ☐ Exc

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): May 23, 2025

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): May 23, 2025 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission File Num

ASP Isotopes Inc. 601 Pennsylvania Avenue NW South Building, Suite 900 Washington, DC 20004 May 27, 2025

ASP Isotopes Inc. 601 Pennsylvania Avenue NW South Building, Suite 900 Washington, DC 20004 May 27, 2025 VIA EDGAR Securities and Exchange Commission Division of Corporation Finance 100 F Street, N.E. Washington, D.C. 20549 Attention: Robert Augustin Re: ASP Isotopes Inc. Registration Statement on Form S-3 File No. 333-286860 Acceleration Request Requested Date: Friday, May 30, 2025 Requested Time

UNAUDITED PRO FORMA CONDENSED COMBINED FINANCIAL STATEMENTS

EXHIBIT 99.3 UNAUDITED PRO FORMA CONDENSED COMBINED FINANCIAL STATEMENTS The following unaudited pro forma condensed combined financial statements of ASP Isotopes Inc. (the “Company”) and Renergen Limited, a public company incorporated under the laws of the Republic of South Africa (“Renergen”), present the combination of the financial information of the Company and Renergen adjusted to give effec

RISK FACTORS

EXHIBIT 99.1 RISK FACTORS Unless stated otherwise or dictated by context, all capitalized terms used herein but not defined shall have the meanings set forth in the Current Report on Form 8-K filed by ASP Isotopes Inc., a Delaware corporation (the “Company”), with the Securities and Exchange Commission to which this risk factors document is attached (the “Form 8-K”). The following risks and uncert

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): May 27, 2025

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): May 27, 2025 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission File Num

INDEX TO FINANCIAL STATEMENTS

EXHIBIT 99.2 INDEX TO FINANCIAL STATEMENTS Page RENERGEN LIMITED Audited Consolidated Financial Statements Report of Independent Registered Public Accounting Firm (PCAOB ID 1368) 2 Consolidated Statement of Financial Position as of February 28, 2025 and February 29, 2024 3 Consolidated Statement of Profit or Loss and Other Comprehensive Loss for the years ended February 28, 2025 and February 29, 2

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): May 16, 2025

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): May 16, 2025 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission File Num

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form CB TENDER OFFER/RIGHTS OFFERING NOTIFICATION FORM (AMENDMENT NO. 1)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form CB TENDER OFFER/RIGHTS OFFERING NOTIFICATION FORM (AMENDMENT NO. 1) Please place an X in the box(es) to designate the appropriate rule provision(s) relied upon to file this Form: Securities Act Rule 801 (Rights Offering) ☐ Securities Act Rule 802 (Exchange Offer) ☒ Exchange Act Rule 13e-4(h)(8) (Issuer Tender Offer) ☐ Exc

Loan Agreement, dated May 16, 2025, by and between QLE TP Funding SPE LLC, as borrower, and TerraPower, LLC, as lender.

EXHIBIT 10.1 Execution Copy LOAN AGREEMENT BY AND BETWEEN QLE TP FUNDING SPE LLC, a Delaware limited liability company, AS BORROWER AND TERRAPOWER, LLC, a Delaware limited liability company AS LENDER Dated: May 16, 2025 1 TABLE OF CONTENTS ARTICLE I DEFINITIONS AND INTERPRETATIONS 5 Section 1.1 Definitions 5 Section 1.2 Singular and Plural Terms 16 Section 1.3 Accounting Principles 16 Section 1.4

Merger Notice Form CC 4(1) and Merger Notice Form CC 4(2) were made publicly available in accordance with the requirements of Renergen’s home jurisdiction.

EXHIBIT 99.6

The Press Release of ASP Isotopes Inc. dated May 20, 2025 and entitled “ASP Isotopes Inc. Announces an Agreement Relating to the Potential Acquisition of Renergen Limited Expected to Create a Global Critical Materials Company” was made publicly available in the United States.

EXHIBIT 99.4 ASP Isotopes Inc. Announces an Agreement Relating to the Potential Acquisition of Renergen Limited Expected to Create a Global Critical Materials Company - Combining these two highly complementary businesses aims to create a global leader in the production of critical and strategically important materials, including electronic gases such as helium, various fluorinated products and iso

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form CB TENDER OFFER/RIGHTS OFFERING NOTIFICATION FORM (AMENDMENT NO. )

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form CB TENDER OFFER/RIGHTS OFFERING NOTIFICATION FORM (AMENDMENT NO. ) Please place an X in the box(es) to designate the appropriate rule provision(s) relied upon to file this Form: Securities Act Rule 801 (Rights Offering) ☐ Securities Act Rule 802 (Exchange Offer) ☒ Exchange Act Rule 13e-4(h)(8) (Issuer Tender Offer) ☐ Exch

Joint Firm Intention Announcement dated May 20, 2025 made by ASP Isotopes Inc. and Renergen was made publicly available in accordance with the requirements of Renergen’s home jurisdiction.

EXHIBIT 99.3 RENERGEN LIMITED (Incorporated in the Republic of South Africa) (Registration number 2014/195093/06) JSE and A2X Share code: REN ISIN: ZAE000202610 LEI:378900B1512179F35A69 Australian Business Number (ABN): 93 998 352 675 ASX Share code: RLT ASP ISOTOPES INC. (Incorporated in the State of Delaware, United States of America) (Delaware file number 6228898) Ticker Symbol: NASDAQ: ASPI IS

ASP Isotopes Inc. enters into Definitive Agreements with TerraPower including Loan Agreement for Construction of a HALEU Production Facility and Supply Agreements for HALEU

EXHIBIT 99.1 ASP Isotopes Inc. enters into Definitive Agreements with TerraPower including Loan Agreement for Construction of a HALEU Production Facility and Supply Agreements for HALEU - Loan Agreement with TerraPower provides a term loan subject to conditions to support construction of a new uranium enrichment facility at Pelindaba, South Africa. - Supply Agreement supports the supply of HALEU f

Regulation FD Disclosure, Entry into a Material Definitive Agreement, Unregistered Sales of Equity Securities, Financial Statements and Exhibits, Other Events

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): May 19, 2025 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission File Num

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): May 19, 2025

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): May 19, 2025 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission File Num

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q (Mark One)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2025 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-41555 ASP Isotopes Inc.

ASP Isotopes Inc. Announces an Agreement Relating to the Potential Acquisition of Renergen Limited Expected to Create a Global Critical Materials Company

EXHIBIT 99.2 ASP Isotopes Inc. Announces an Agreement Relating to the Potential Acquisition of Renergen Limited Expected to Create a Global Critical Materials Company - Combining these two highly complementary businesses aims to create a global leader in the production of critical and strategically important materials, including electronic gases such as helium, various fluorinated products and iso

Firm Intention Letter Agreement, dated May 20,2025, by and between ASP Isotopes Inc. and Renergen Limited.

EXHIBIT 2.1 To: The Directors (Renergen Board) Renergen Limited Address: Sandton Gate, Second Floor, 25 Minerva Avenue, Glenadrienne, Sandton, Gauteng, 2196 Attention: The Chairman Dear Sirs FIRM INTENTION BY ASP ISOTOPES INC. (ASPI) TO MAKE AN OFFER TO ACQUIRE ALL ISSUED ORDINARY SHARES IN RENERGEN LIMITED (THE COMPANY) (ASPI AND THE COMPANY COLLECTIVELY REFERRED TO AS THE PARTIES, AND EACH A PAR

Investor presentation dated May 20,2025.

EXHIBIT 99.1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56

RENERGEN LIMITED (Incorporated in the Republic of South Africa) (Registration number 2014/195093/06) JSE and A2X Share code: REN ISIN: ZAE000202610 Australian Business Number (ABN): 93 998 352 675 ASX Share code: RLT

EXHIBIT 99.3 RENERGEN LIMITED (Incorporated in the Republic of South Africa) (Registration number 2014/195093/06) JSE and A2X Share code: REN ISIN: ZAE000202610 LEI:378900B1512179F35A69 Australian Business Number (ABN): 93 998 352 675 ASX Share code: RLT (“Renergen”) ASP ISOTOPES INC. (Incorporated in the State of Delaware, United States of America) (Delaware file number 6228898) Ticker Symbol: NA

Loan Agreement, dated May 19, 2025, by and among ASP Isotopes Inc., ASP Isotopes South Africa Proprietary Limited, as lender, and Renergen Limited, as borrower.

EXHIBIT 10.1 TERM LOAN FACILITY AGREEMENT Between ASP ISOTOPES INCORPORATED and ASP ISOTOPES SOUTH AFRICA PROPRIETARY LIMITED and RENERGEN LIMITED Page 1 Table of Contents 1. PARTIES 3 2. BACKGROUND 3 3. DEFINITIONS 3 4. THE FACILITY 11 5. TERMINATION OF EXCLUSIVETY AGREEMENT 12 6. ADVANCECONDITIONS 12 7. ADVANCES 13 8. DRAWDOWNNOTICES 13 9. INTEREST 14 10. REPAYMENT OF INTEREST AND THE LOAN 14 11

OMB APPROVAL

OMB APPROVAL OMB Number: 3235-0058 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Expires: May 31, 2025 Estimated average burden Washington, D.

LETTER

May 8, 2025 Paul Mann Executive Chairman and Chief Executive Officer ASP Isotopes Inc.

Form of indenture for subordinated debt securities and the related form of subordinated debt security.

EXHIBIT 4.2 ASP ISOTOPES INC. ISSUER AND [TRUSTEE], TRUSTEE INDENTURE DATED AS OF , 20 SUBORDINATED DEBT SECURITIES TABLE OF CONTENTS Page ARTICLE ONE. - DEFINITIONS AND OTHER PROVISIONS OF GENERAL APPLICATION 2 Section 101. Definitions 2 Section 102. Compliance Certificates and Opinions 11 Section 103. Form of Documents Delivered to Trustee 12 Section 104. Acts of Holders 12 Section 105. Notices,

Equity Distribution Agreement, dated April 30, 2025, by and between ASP Isotopes Inc. and Canaccord Genuity LLC.

EXHIBIT 1.2 ASP Isotopes Inc. Common Stock (par value $0.01 per share) $25,000,000 EQUITY DISTRIBUTION AGREEMENT April 30, 2025 Canaccord Genuity LLC 1 Post Office Square Suite 3000 Boston, Massachusetts 02109 Ladies and Gentlemen: ASP Isotopes Inc., a Delaware corporation (the “Company”), confirms this agreement (this “Agreement”) with Canaccord Genuity LLC (the “Manager”) as follows: SECTION 1:

As filed with the Securities and Exchange Commission on April 30, 2025

As filed with the Securities and Exchange Commission on April 30, 2025 Registration No.

Filing Fee Table

EXHIBIT 107 Calculation of Filing Fee Tables Form S-3 (Form Type) ASP Isotopes Inc.

Form of indenture for senior debt securities and the related form of senior debt security.

EXHIBIT 4.1 ASP ISOTOPES INC. ISSUER AND [TRUSTEE], TRUSTEE INDENTURE DATED AS OF , 20 SENIOR DEBT SECURITIES TABLE OF CONTENTS Page ARTICLE One. - DEFINITIONS AND OTHER PROVISIONS OF GENERAL APPLICATION 2 SECTION 101. Definitions 2 SECTION 102. Compliance Certificates and Opinions 11 SECTION 103. Form of Documents Delivered to Trustee 12 SECTION 104. Acts of Holders 12 SECTION 105. Notices, etc.,

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K/A (Amendment No. 1)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K/A (Amendment No. 1) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the year ended December 31, 2024 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number 001-41555 ASP Isotopes

Regulation FD Disclosure, Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits

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): April 14, 2025 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission File N

ASP Isotopes Inc. Announces Changes in Boards of ASP Isotopes Inc. and Quantum Leap Energy LLC

EXHIBIT 99.1 ASP Isotopes Inc. Announces Changes in Boards of ASP Isotopes Inc. and Quantum Leap Energy LLC - Highly respected South African Businessman, Mr Sipho Maseko, former CEO of Telkom SA Soc Ltd and MD of Vodacom SA, Has Joined the Board of Directors of ASP Isotopes Inc. - Dr. Hendrik Strydom, PhD, Chief Technology Officer of ASP Isotopes Inc., is transitioning from the Board of Directors

As filed with the Securities and Exchange Commission on April 8, 2025

As filed with the Securities and Exchange Commission on April 8, 2025 Registration No.

Filing Fee Table

EXHIBIT 107 Calculation of Filing Fee Tables FORM S-8 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 ASP ISOTOPES INC.

Regulation FD Disclosure, Financial Statements and Exhibits

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): April 1, 2025 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission File Nu

ASP Isotopes Inc. Completes Commissioning of First Quantum Enrichment Laser System and Starts Production of Commercial Samples of Ytterbium-176

EXHIBIT 99.1 ASP Isotopes Inc. Completes Commissioning of First Quantum Enrichment Laser System and Starts Production of Commercial Samples of Ytterbium-176 - Ytterbium-176 is a critical material used in the production of radioisotopes for oncology treatments, including Novartis’ Pluvicto. - The Company expects to be able to achieve a 99.75% enrichment for Ytterbium-176 and offer highly enriched Y

List of Subsidiaries of the Registrant

EXHIBIT 21.1 ASP Isotopes Inc. Subsidiaries of the Registrant Subsidiaries* Place of Incorporation ASP Isotopes Guernsey Limited (formerly, PDS-Photonica Holdings (Guernsey) Limited) Guernsey ASP Isotopes South Africa (Proprietary) Limited (formerly, PDS Photonica Holdings South Africa (PTY) Limited) South Africa Enlightened Isotopes (Pty) Ltd South Africa ASPI South Africa Asset Finance South Afr

ASP Isotopes Inc. Announces Fourth Quarter and Fiscal Year 2024 Financial Results Webinar

EX-99.1 2 aspiex991.htm PRESS RELEASE EXHIBIT 99.1 ASP Isotopes Inc. Announces Fourth Quarter and Fiscal Year 2024 Financial Results Webinar Washington, D.C., March 31, 2025 (GLOBE NEWSWIRE) - ASP Isotopes Inc. NASDAQ: ASPI (“ASP Isotopes” or the “Company”), announced that it will release its fourth quarter and fiscal year 2024 financial results after the close of financial markets today, March 31

Insider Trading Policy

Exhibit 19.1 ASP ISOTOPES INC. INSIDER TRADING POLICY As adopted by the Board of Directors as of December 9, 2024 Table of Contents Page Section 1. All Employees, Officers, Directors and their Family Members and Affiliates Are Subject to this Policy 1 Section 2. Trading in ASP Isotopes Securities While in Possession of Material Nonpublic Information is Prohibited 1 Section 3. Trading Window 1 Sect

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the year ended December 31, 2024 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number 001-41555 ASP Isotopes Inc. (Exact name of

Regulation FD Disclosure, Financial Statements and Exhibits

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): March 31, 2025 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission File N

Non-Employee Director Compensation Policy adopted effective October 30, 2024.

Exhibit 10.31 ASP Isotopes Inc. Non-Employee Director Compensation Policy Each individual who provides services to ASP Isotopes Inc. (the “Company”) as a member of the Board of Directors (the “Board”), other than any director who is employed by the Company or one of its subsidiaries (a “Covered Non-Employee Director”), will be entitled to receive the following amounts of compensation, subject to t

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): March 27, 2025

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): March 27, 2025 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission File N

ASP Isotopes Inc. Commences Commercial Production of Enriched Silicon-28 at its Second Aerodynamic Separation Process (ASP) Enrichment Facility

EXHIBIT 99.1 ASP Isotopes Inc. Commences Commercial Production of Enriched Silicon-28 at its Second Aerodynamic Separation Process (ASP) Enrichment Facility - Silicon-28 is an isotope that is believed to assist in enabling quantum computing and improving the performance of next generation semiconductors for artificial intelligence. - The Company expects to ship commercial product during 2Q25. - Th

ASP Isotopes Inc. Commences Commercial Production of Enriched Carbon-14 at its First Aerodynamic Separation Process (ASP) Enrichment Facility

EXHIBIT 99.1 ASP Isotopes Inc. Commences Commercial Production of Enriched Carbon-14 at its First Aerodynamic Separation Process (ASP) Enrichment Facility - The Company has commenced commercial production of enriched Carbon-14 at its first Aerodynamic Separation Process (ASP) enrichment facility. - The Company expects to ship commercial product around the middle of the year. - The Company previous

Regulation FD Disclosure, Financial Statements and Exhibits

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): February 26, 2025 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission Fil

EX-24

EX-24 2 PowerOfAttorney.txt EXHIBIT 24: POWER OF ATTORNEY POWER OF ATTORNEY The undersigned, BlackRock, Inc., a corporation duly organized under the laws of the State of Delaware, United States (the "Company"), does hereby make, constitute and appoint each of Eric Andruczyk, Richard Cundiff, R. Andrew Dickson, III, Spencer Fleming, Laura Hildner, David Maryles, Christopher Meade, Charles Park, Jam

EX-99

EX-99 3 ITEM7.txt EXHIBIT 99: ITEM 7 BlackRock Advisors, LLC Aperio Group, LLC BlackRock Asset Management Canada Limited BlackRock Fund Advisors BlackRock Institutional Trust Company, National Association BlackRock Financial Management, Inc. BlackRock Investment Management, LLC *Entity beneficially owns 5% or greater of the outstanding shares of the security class being reported on this Schedule 1

ASP Isotopes Inc. Hosts Investor Access Event in South Africa Providing Updates on its Silicon-28, Ytterbium-176 and Carbon-14 Facilities

EXHIBIT 99.1 ASP Isotopes Inc. Hosts Investor Access Event in South Africa Providing Updates on its Silicon-28, Ytterbium-176 and Carbon-14 Facilities - This week the Company welcomes a group of institutional investors from around the world to its facilities located in Pretoria, South Africa for a two-day investor access event. - During the investor access event, the Company intends to show the in

Regulation FD Disclosure, Financial Statements and Exhibits

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): January 13, 2025 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission File

ASP Isotopes Issues Letter to Shareholders.

EXHIBIT 99.1 ASP Isotopes Issues Letter to Shareholders. Washington, D.C., Dec 16, 2024 (GLOBE NEWSWIRE) - ASP Isotopes Inc. (NASDAQ: ASPI) ("ASP Isotopes” or the “Company”), an advanced materials company dedicated to the development of technology and processes for the production of isotopes for use in multiple industries, today released the following letter to shareholders from its Chairman and C

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): December 16, 2024

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): December 16, 2024 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission Fil

Regulation FD Disclosure, Financial Statements and Exhibits

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): December 13, 2024 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission Fil

ASP Isotopes Inc. Responds To Short Seller “Report”

EXHIBIT 99.1 ASP Isotopes Inc. Responds To Short Seller “Report” Washington, D.C., December 13, 2024 (GLOBE NEWSWIRE) - ASP Isotopes Inc. NASDAQ: ASPI (“ASP Isotopes” or the “Company”), an advanced materials company dedicated to the development of technology and processes for the production of isotopes for use in multiple industries, today issued the following statement in response to short seller

ASP Isotopes Inc. to host Investor Access Event in South Africa from January 14-16, 2025

EXHIBIT 99.1 ASP Isotopes Inc. to host Investor Access Event in South Africa from January 14-16, 2025 Washington, D.C., December 2, 2024 (GLOBE NEWSWIRE) - ASP Isotopes Inc. NASDAQ: ASPI ("ASP Isotopes” or the “Company”), an advanced materials company dedicated to the development of technology and processes for the production of isotopes for use in multiple industries, today announced that it will

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): December 2, 2024

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): December 2, 2024 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission File

ASP Isotopes Inc. Responds to Short Seller Report

EXHIBIT 99.1 ASP Isotopes Inc. Responds to Short Seller Report Washington, D.C., November 26, 2024 (GLOBE NEWSWIRE) - ASP Isotopes Inc. NASDAQ: ASPI ("ASP Isotopes” or the “Company”), an advanced materials company dedicated to the development of technology and processes for the production of isotopes for use in multiple industries, today issued the following statement in response to a short seller

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): November 26, 2024

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): November 26, 2024 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission Fil

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): November 26, 2024

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): November 26, 2024 ASP Isotopes Inc. (Exact name of registrant as specified in its charter) Delaware 001-41555 87-2618235 (State or other jurisdiction of incorporation) (Commission Fil

ASP Isotopes Inc. Completes Construction and Starts the Commissioning of Silicon-28 Enrichment Facility

EXHIBIT 99.1 ASP Isotopes Inc. Completes Construction and Starts the Commissioning of Silicon-28 Enrichment Facility - Construction of the Company’s Silicon-28 enrichment facility has been completed in line with previously communicated timelines. - Silicon-28 is an isotope that is believed to enable quantum computing and will likely improve the performance of next generation semiconductors for art

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

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): November 20, 2024 ASP Isotopes Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-41555 87-2618235 (State or Other Jurisdiction of Incorporation) (Commission Fil

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q (Mark One)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2024 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-41555 ASP Isotopes Inc.

Executive Employment Agreement by and between the Company and Heather Kiessling, dated June 10, 2024 (incorporated by reference to Exhibit 10.1 to the Form 10-Q filed on November 19, 2024).

Exhibit 10.1 EXECUTIVE EMPLOYMENT AGREEMENT This EXECUTIVE EMPLOYMENT AGREEMENT (“Agreement”) is made and entered into as of the 10th day of June, 2024 by and between ASP Isotopes Inc., a Delaware corporation (the “Company”), and Heather Kiessling (“Executive”). As used herein, the “Effective Date” of this Agreement shall mean July 1, 2024 or such earlier date as mutually agreed to by Executive an