Terrestrial Energy Inc. /DE/ 10-K

ITEM 9A. CONTROLS AND PROCEDURES Evaluation of Disclosure Controls and Procedures Disclosure controls and procedures are controls and other procedures designed to ensure that information required to be disclosed in our reports filed or submitted under the Exchange Act is recorded, processed, summarized and reported within the time periods specified in the SEC’s rules and forms. Disclosure controls and procedures include, without limitation, controls and procedures designed to ensure that information required to be disclosed in our reports filed or submitted under the Exchange Act is accumulated and communicated to Management, including our Chief Executive Officer and Chief Financial Officer (together, the “Certifying Officers”), or persons performing similar functions, as appropriate, to allow timely decisions regarding required disclosure. Under the supervision and with the participation of our Management, including our Certifying Officers, we carried out an evaluation of the effectiveness of the design and operation of our disclosure controls and procedures as defined in Rules 13a-15(e) and 15d-15(e) under the Exchange Act. Based on the foregoing, our Certifying Officers concluded that our disclosure controls and procedures were effective as of the end of the fiscal year ended December 31, 2025. Accordingly, Management believes that the financial statement contained elsewhere in this Report present fairly in all material respects our financial position, results of operations and cash flows for the period presented. We do not expect that our disclosure controls and procedures will prevent all errors and all instances of fraud. Disclosure controls and procedures, no matter how well conceived and operated, can provide only reasonable, not absolute, assurance that the objectives of the disclosure controls and procedures are met. Further, the design of disclosure controls and procedures must reflect the fact that there are resource constraints, and the benefits must be considered relative to their costs. Because of the inherent limitations in all disclosure controls and procedures, no evaluation of disclosure controls and procedures can provide absolute assurance that we have detected all our control deficiencies and instances of fraud, if any. The design of disclosure controls and procedures also is based partly on certain assumptions about the likelihood of future events, and there can be no assurance that any design will succeed in achieving its stated goals under all potential future conditions. Management’s Annual Report on Internal Controls over Financial Reporting This Report does not include an attestation report of our internal controls from our independent registered public accounting firm due to our status as an emerging growth company under the JOBS Act. Changes in Internal Control over Financial Reporting There were no changes in our internal control over financial reporting identified in connection with the evaluation required by Rule 13a-15(d) under the Exchange Act during the three months ended December 31, 2025, that have materially affected, or are reasonably likely to materially affect, our internal control over financial reporting. ITEM 9B. OTHER INFORMATION Rule 10b5-1 Trading Plans During the fourth quarter of 2025, none of the Company’s directors or executive officers adopted , modified or terminated any “Rule 10b5-1 trading arrangement” or any “non-Rule 10b5-1 trading arrangement,” as each term is defined in Item 408 of Regulation S-K. 72 Table of Contents Delaware Certificate of Correction On March 27, 2026, the Company filed a Certificate of Correction (the “Certificate of Correction”) with the Secretary of State of the State of Delaware in connection with the Company’s Certificate of Incorporation filed on October 23, 2025 (the “Charter”). The Certificate of Correction was filed to update Article II of the Charter to reflect the correct name and address of the Company’s registered agent. Other than disclosed herein, no additional changes have been made to the Charter. The as-corrected text of the Charter is included as Exhibit 3.1 to this Annual Report. ITEM 9C. DISCLOSURE REGARDING FOREIGN JURISDICTIONS THAT PREVENT INSPECTIONS Not applicable. ​ 73 Table of Contents PART III ITEM 10. DIRECTORS, EXECUTIVE OFFICERS AND CORPORATE GOVERNANCE The information required under this item is incorporated herein by reference to our proxy statement for our 2026 Annual Meeting of Stockholders to be filed with the SEC not later than 120 days after December 31, 2025. ​ ITEM 11. EXECUTIVE COMPENSATION The information required under this item is incorporated herein by reference to our proxy statement for our 2026 Annual Meeting of Stockholders to be filed with the SEC not later than 120 days after December 31, 2025. ITEM 12. SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT AND RELATED STOCKHOLDER MATTERS The information required under this item is incorporated herein by reference to our proxy statement for our 2026 Annual Meeting of Stockholders to be filed with the SEC not later than 120 days after December 31, 2025. ITEM 13. CERTAIN RELATIONSHIPS AND RELATED TRANSACTIONS, AND DIRECTOR INDEPENDENCE The information required under this item is incorporated herein by reference to our proxy statement for our 2026 Annual Meeting of Stockholders to be filed with the SEC not later than 120 days after December 31, 2025. ITEM 14. PRINCIPAL ACCOUNTANT FEES AND SERVICES The information required under this item is incorporated herein by reference to our proxy statement for our 2026 Annual Meeting of Stockholders to be filed with the SEC not later than 120 days after December 31, 2025. ​ ​ ​ 74 Table of Contents PART IV ITEM 15. EXHIBITS AND FINANCIAL STATEMENT SCHEDULES (a) 1. Financial Statements. See “Part II. Item 8. Financial Statements and Supplementary Data” 2. Financial Statement Schedule. See “Part II. Item 8. Financial Statements and Supplementary Data” 3. Exhibit Index: ​ ​ ​ ​ Incorporated by Reference Herein ​ Exhibit Number ​ ​ ​ Description ​ ​ ​ Form ​ ​ ​ Exhibit ​ ​ ​ Date Filed with the SEC File Number ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2.1 # Business Combination Agreement, dated as of March 26, 2025, by and among HCM II Acquisition Corp., HCM II Merger Sub Inc., and Terrestrial Energy Inc. ​ S-4/A ​ 2.1 ​ September 23, 2025 001-42252 2.2 ​ Amendment No. 1 to Business Combination Agreement, effective as of October 26, 2025, by and among HCM II Acquisition Corp., HCM II Merger Sub Inc., and Terrestrial Energy Inc. ​ 8-K ​ 2.2 ​ November 3, 2025 001-42252 2.3 ​ Certificate of Merger of HCM II Merger Sub Inc. with and into Terrestrial Energy Inc. ​ 8-K ​ 2.3 ​ November 3, 2025 001-42252 2.4 ​ Plan of Domestication ​ 8-K ​ 2.4 ​ November 3, 2025 001-42252 3.1 * Composite Certificate of Incorporation of Terrestrial Energy Inc. (as amended through March 27, 2026) ​ ​ ​ ​ ​ ​ ​ 3.2 * Composite Bylaws of Terrestrial Energy Inc. (as amended through October 28, 2026) ​ ​ ​ ​ ​ ​ ​ 3.3 * Certificate of Designations for Special Voting Preferred Stock ​ ​ ​ ​ ​ ​ ​ 4.1 ​ Specimen Common Stock Certificate of Terrestrial Energy Inc. ​ S-4/A ​ 4.5 ​ September 23, 2025 333-288735 4.2 * Specimen Warrant Certificate of Terrestrial Energy Inc. ​ ​ ​ 10.1 ​ Amended and Restated Warrant Agreement, dated October 28, 2025, by and between the Company and Continental Stock Transfer & Trust Company, as warrant agent ​ 8-K ​ 10.1 ​ November 3, 2025 001-42252 10.2 ​ Assignment and Assumption Agreement dated October 28, 2025 by and between Terrestrial Energy Inc. and HCM II Acquisition Corp. ​ 8-K ​ 10.2 ​ November 3, 2025 001-42252 75 Table of Contents ​ ​ ​ ​ Incorporated by Reference Herein ​ Exhibit Number ​ ​ ​ Description ​ ​ ​ Form ​ ​ ​ Exhibit ​ ​ ​ Date Filed with the SEC File Number ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 10.3 ​ Amended and Restated Registration Rights Agreement, dated as of October 28, 2025, by and among Terrestrial Energy Inc., Cantor Fitzgerald & Co. and HCM Investor Holdings II, LLC. ​ 8-K ​ 10.3 ​ November 3, 2025 001-42252 10.4 ​ Sponsor Support Agreement, by and among HCM II Acquisition Corp., HCM Investor Holdings II, LLC, and the other parties thereto ​ S-4/A ​ 10.2 ​ September 23, 2025 333-288735 10.5 ​ Sponsor Lock-Up Agreement, dated as of October 28, 2025, by and among Terrestrial Energy Inc. and HCM Investor Holdings II, LLC. ​ 8-K ​ 10.5 ​ November 3, 2025 001-42252 10.6 ​ Form of Key Holders Lock-Up Agreement, dated October 27, 2025, by and among HCM II Acquisition Corp. and the other parties thereto ​ S-4/A ​ 10.7 ​ September 23, 2025 333-288735 10.7 ​ Second Amended and Restated Exchange and Support Agreement dated October 28, 2025, by and among HCM Acquisition Corp., Terrestrial Energy Canada (Call) Inc., and Terrestrial Energy Canada (Exchange) Inc. ​ 8-K ​ 10.7 ​ November 3, 2025 001-42252 10.8 ​ Form of PIPE Subscription Agreement ​ S-4/A ​ 4.8 ​ September 23, 2025 333-288735 10.9 ‡ Terrestrial Energy Inc. 2025 Equity Incentive Plan ​ 8-K ​ 10.9 ​ November 3, 2025 001-42252 10.10 ‡* Form of Restricted Stock Unit Award under 2025 Plan ​ ​ ​ ​ ​ ​ ​ 10.11 ‡* Form of Stock Option Award under 2025 Plan ​ ​ ​ ​ ​ ​ ​ 10.12 ‡ Terrestrial Energy Inc. Second Amended and Restated 2024 Stock Option Plan ​ S-8 ​ 10.2 ​ January 5, 2026 333-292571 10.13 ‡* Form of Option Agreement under 2024 Plan ​ ​ ​ ​ ​ ​ ​ 10.14 ‡ Employment Agreement, dated as of October 28, 2025, by and between Simon Irish and Terrestrial Energy Development Inc . ​ 8-K ​ 10.10 ​ November 3, 2025 001-42252 76 Table of Contents ​ ​ ​ ​ Incorporated by Reference Herein ​ Exhibit Number ​ ​ ​ Description ​ ​ ​ Form ​ ​ ​ Exhibit ​ ​ ​ Date Filed with the SEC File Number ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 10.15 ‡* Assignment, Assumption, Waiver and Covenant Agreement, dated as of February 18, 2026, by and between Simon Irish, Terrestrial Energy Inc., and Terrestrial Energy Development Inc. ​ ​ ​ ​ ​ ​ ​ 10.16 ‡ Form of Indemnification Agreement between New Terrestrial Energy and each of its directors and executive officers. ​ 8-K ​ 10.11 ​ November 3, 2025 001-42252 10.17 ‡* Non-Employee Director Compensation Policy ​ ​ ​ ​ ​ ​ ​ 19.1 * Terrestrial Energy Inc. Insider Trading Policy ​ ​ ​ ​ ​ ​ ​ 21.1 List of Subsidiaries of Terrestrial Energy Inc. ​ 8-K ​ 21.1 ​ November 3, 2025 001-42252 23.1 * Consent of UHY LLP ​ ​ ​ ​ ​ ​ ​ 31.1 * Certification by the Chief Executive Officer pursuant to Section 302 of the Sarbanes-Oxley Act of 2002 ​ ​ ​ ​ ​ ​ ​ 31.2 * Certification by the Chief Financial Officer pursuant to Section 302 of the Sarbanes-Oxley Act of 2002 ​ ​ ​ ​ ​ ​ ​ 32.1 ** Certification by the Chief Executive Officer and Chief Financial Officer pursuant to Section 906 of the Sarbanes-Oxley Act of 2002 ​ ​ ​ ​ ​ ​ ​ 97.1 Policy Relating to Recovery of Erroneously Awarded Compensation ​ 10-K ​ 97.1 ​ March 31, 2025 001-42252 101.INS * Inline XBRL Instance Document (1) ​ ​ ​ ​ ​ ​ ​ 101.SCH * Inline XBRL Taxonomy Extension Schema Document ​ ​ ​ ​ ​ ​ ​ 101.CAL * Inline XBRL Taxonomy Extension Calculation Linkbase Document ​ ​ ​ ​ ​ ​ ​ 101.DEF * Inline XBRL Taxonomy Extension Definition Linkbase Document ​ ​ ​ ​ ​ ​ ​ 101.LAB * Inline XBRL Taxonomy Extension Label Linkbase Document ​ ​ ​ ​ ​ ​ ​ 101.PRE * Inline XBRL Taxonomy Extension Presentation Linkbase Document ​ ​ ​ ​ ​ ​ ​ 104 * Cover Page Interactive Data File (2) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ‡ Management contract or compensatory plan or arrangement * Filed herewith 77 Table of Contents ** Furnished herewith # Certain schedules and similar attachments to this Exhibit have been omitted in accordance with Item 601(a)(5) of Regulation S-K. The Company agrees to furnish supplementally a copy of any omitted exhibit or schedule to SEC upon its request. (1) The instance document does not appear in the Interactive Data File because its XBRL tags are embedded within the Inline XBRL document (2) Formatted in Inline XBRL and contained in exhibit 101 ​ ​ ITEM 16. FORM 10-K SUMMARY None. ​ ​ ​ 78 Table of Contents SIGNATURES Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized. ​ ​ ​ ​ TERRESTRIAL ENERGY INC. ​ ​ ​ ​ By: /s/ Brian Thrasher ​ ​ Brian Thrasher ​ ​ Chief Financial Officer ​ ​ (Principal Financial Officer) ​ Date: March 30, 2026 Pursuant to the requirements of the Securities Exchange Act of 1934, this report has been signed below by the following persons on behalf of the registrant and in the capacities and on the dates indicated. ​ ​ ​ ​ ​ ​ ​ ​ Signature ​ ​ ​ Title ​ ​ ​ Date ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ /s/ Simon Irish ​ Chief Executive Officer and Director ​ March 30, 2026 Simon Irish ​ (Principal Executive Officer) ​ ​ ​ ​ /s/ Brian Thrasher ​ Chief Financial Officer ​ ​ Brian Thrasher ​ (Principal Financial and Accounting Officer) ​ March 30, 2026 ​ ​ ​ ​ ​ /s/ Frederick Buckman ​ Chairman of the Board of Directors ​ ​ Frederick Buckman ​ ​ March 30, 2026 ​ ​ ​ ​ ​ /s/ Shawn Matthews ​ Director ​ March 30, 2026 Shawn Matthews ​ ​ ​ ​ ​ ​ ​ /s/ Hugh MacDiarmid ​ Director ​ March 30, 2026 Hugh MacDiarmid ​ ​ ​ ​ ​ ​ ​ /s/ David Hill ​ Director ​ March 30, 2026 David Hill ​ ​ ​ ​ ​ ​ /s/ Charles Pardee ​ Director ​ March 30, 2026 Charles Pardee ​ ​ ​ ​ ​ ​ ​ ​ ​ /s/ Robert W. Jones ​ Director ​ March 30, 2026 Robert W. Jones ​ ​ ​ ​ ​ ​ ​ ​ ​ /s/ William Johnson ​ Director ​ March 30, 2026 William Johnson ​ ​ ​ ​ ​ ​ ​ ​ ​ /s/ David LeBlanc ​ Director ​ March 30, 2026 David LeBlanc ​ ​ ​ ​ ​ ​ 79