Results of Operations and Financial Condition. ​ On August 11, 2026, Terrestrial Energy Inc. announced its financial and operating results for the quarter ended June 30, 2026. A copy of the press release is furnished herewith as Exhibit 99.1 and incorporated herein by reference. ​ The information set forth under this Item 2.02, including Exhibit 99.1, is intended to be furnished and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the…

Director — Shawn Matthews: Mr. Matthews resigned from the Board of Directors without any disagreement on matters relating to the Company’s operations, policies or practices.

Director — Kathryn McCarthy: Appointment of Kathryn McCarthy as a director of the Company.

General Counsel, Secretary and Chief Compliance Officer — Steven Millsap: Steven Millsap's employment will be ending effective September 12, 2026.

Results of Operations and Financial Condition. ​ On May 14, 2026, Terrestrial Energy Inc. announced its financial and operating results for the quarter ended March 31, 2026. A copy of the press release is furnished herewith as Exhibit 99.1 and incorporated herein by reference. ​ The information set forth under this Item 2.02, including Exhibit 99.1, is intended to be furnished and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “E…

Director — David Hill: David Hill resigned from the Board of Directors.

The filing details new employment agreements for existing executive officers, without indicating any departures or significant changes in roles.

Results of Operations and Financial Condition. ​ On March 30, 2026, Terrestrial Energy Inc. announced its financial and operating results for the year and quarter ended December 31, 2025. A copy of the press release is furnished herewith as Exhibit 99.1 and incorporated herein by reference. ​ The information set forth under this Item 2.02, including Exhibit 99.1, is intended to be furnished and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as a…

Changes in Registrant’s Certifying Accountant. (a) Dismissal of independent registered public accounting firm. On November 21, 2025, the Audit Committee approved the dismissal of WithumSmith+Brown, PC (“ Withum ”), the independent registered public accounting firm of HCM II prior to the consummation of the Merger, as the independent registered public accounting firm of the Registrant, effective as of the date of notice to Withum, which was delivered to Withum on Monday, November 24, 2025. The…

of this Current Report is incorporated by reference herein. Description of Registrant’s Securities to Be Registered The description of New Terrestrial Energy’s securities is contained in the Proxy Statement/Prospectus in the section titled “ Description of New Terrestrial Energy’s Securities .” The information set forth under

Mr. Irish: The filing describes an RSU agreement and its terms, not a management change.

Entry into a Material Definitive Agreement. Indemnification Agreements In connection with the consummation of the Transactions and as contemplated by the Business Combination Agreement, New Terrestrial Energy entered into indemnification agreements with each of its directors and executive officers. Each indemnification agreement provides for indemnification and advancement by New Terrestrial Energy of certain expenses and costs relating to claims, suits, or proceedings arising from service to…

of this Current Report by reference. A more complete summary of the material provisions of the Business Combination Agreement is included in the Proxy Statement/Prospectus titled “ The Business Combination Proposal ” beginning on page 111, which is incorporated by reference herein. 5 FORM 10 INFORMATION Item 2.01(f) of Form 8-K provides that if the predecessor registrant was a “shell company” (as such term is defined in Rule 12b-2 under the Exchange Act), as HCM II was immediately before the…

Changes in Control of Registrant. The information set forth above under the Introductory Note and

Material Modification to Rights of Security Holders. On October 23, 2025, in connection with the Domestication, HCM II filed the Certificate of Incorporation with the Secretary of State of the State of Delaware. The material terms of the Certificate of Incorporation and HCM II’s bylaws (as amended from time to time, the “ Bylaws ”) and the general effect upon the rights of holders of HCM II’s capital stock are discussed in the Proxy Statement/Prospectus in the sections titled “ The Domesticat…

by reference. On October 23, 2025, in connection with the Domestication, HCM II filed the Certificate of Incorporation with the Secretary of State of the State of Delaware and adopted its new bylaws (the “Bylaws”). The material terms of the Certificate of Incorporation and the Bylaws, the general effect upon the rights of holders of HCM II’s securities and the terms of the New Terrestrial Common Share and warrants are discussed in the Proxy Statement/Prospectus in the sections titled “The Dom…

Other Events The Merger was consummated on October 28, 2025. New Terrestrial Common Shares and New Terrestrial Warrants began trading on Nasdaq under the symbols “IMSR” and “IMSRW,” respectively, on October 29, 2025. In connection with the Domestication, the name of the Registrant was changed from “HCM II Acquisition Corp.” to “Terrestrial Energy Inc.” The Registrant will file a Form 8-K with additional information regarding the Closing of the Merger within the period prescribed for such form.

is intended to be furnished and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as expressly set forth by specific reference in such filing. On October 20, 2025, the Company issued a press release announcing the approval of…

Other Events. On September 29, 2025, HCM II Acquisition Corp. (“HCM II”) and Terrestrial Energy Inc. (“Terrestrial Energy” or the “Company”) jointly announced that the U.S. Securities and Exchange Commission (the “SEC”) declared effective the Registration Statement on Form S-4, as amended (the “Registration Statement”), filed in connection with the previously announced proposed business combination (the “Business Combination”) between HCM II and Terrestrial Energy. A copy of the press release…

with WithumSmith+Brown, PC, the Company’s independent accounting registered public firm. At this time, the Company does not have an estimate of when all efforts will be completed and when the 2024 Form 10-K/A and 2025 Form 10-Q/A will be filed. Forward-Looking Statements This report may contain forward-looking statements as defined by the Private Securities Litigation Reform Act of 1995. We intend such forward-looking statements to be covered by the safe harbor provisions for forward-looking…

by reference is the investor presentation HCM II and the Company have prepared for use in connection with the Business Combination. The information in this Item 7.01, including Exhibit 99.1 and 99.2 is furnished and will not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “ Exchange Act ”), or otherwise subject to liabilities under that section, and will not be deemed to be incorporated by reference into the filings of HCM II under the Secu…

Unregistered Sales of Equity Securities. The disclosure set forth above in

Entry into a Material Definitive Agreement. Business Combination Agreement On Marc h 26, 2025 (the “ Signing Date ”), HCM II Acquisition Corp, a Cayman Islands exempted company (which will transfer by way of continuation and domesticate as a Delaware corporation prior to the Closing (as defined below)) (“ HCM II ”), entered into a Business Combination Agreement (as it may be amended, supplemented or otherwise modified from time to time in accordance with its terms, the “ Business Combination…

Other Events. Sponsor Lock-Up Agreement At the Closing, the Sponsor will enter into a lock-up agreement (the “ Sponsor Lock-Up Agreement ”), pursuant to which shares of Domesticated Common Stock the Sponsor received upon conversion of its Class A Ordinary Shares (following the Sponsor Share Conversion) in connection with the Domestication (the “ Sponsor Lock-Up Shares ”) and Domesticated Warrants received upon conversion of private placement warrants in connection with the Domestication (the…

Other Events. On August 19, 2024, HCM II Acquisition Corp. (the “ Company ”) consummated its initial public offering (the “ IPO ”) of 23,000,000 units, including 3,000,000 units issued pursuant to the full exercise of the underwriter of its over-allotment option (the “ Units ”). Each Unit consists of one Class A ordinary share of the Company, par value $0.0001 per share (“ Class A Ordinary Shares ”), and one-half of one redeemable warrant of the Company (“ Warrant ”), with each whole Warrant…