SCHEDULE 13G/A 0001352851 XXXXXXXX LIVE 2 Common Stock, par value $0.0001 09/30/2025 0002019804 Terrestrial Energy Inc. 881454102 2730 W. Tyvola Road, Suite 100 Charlotte NC 28217 Rule 13d-1(b) MAGNETAR FINANCIAL LLC DE 0.00 142304.00 0.00 142304.00 142304.00 N 0.62 IA OO MAGNETAR CAPITAL PARTNERS LP DE 0.00 142304.00 0.00 142304.00 142304.00 N 0.62 HC PN SUPERNOVA MANAGEMENT LLC DE 0.00 142304.00 0.00 142304.00 142304.00 N 0.62 HC OO DAVID J. SNYDERMAN X1 0.00 142304.00 0.00 142304.00 142304.00 N 0.62 HC IN Terrestrial Energy Inc. 2730 W. Tyvola Road, Suite 100 Charlotte, NC, 28217 This statement is filed on behalf of each of the following person (collectively, the "Reporting Persons"): i) Magnetar Financial LLC ("Magnetar Financial"); ii) Magnetar Capital Partners LP (Magnetar Capital Partners"); iii) Supernova Management LLC ("Supernova Management"); and iv) David J. Snyderman ("Mr. Snyderman"). This statement relates to the Shares (as defined herein) held for Magnetar Constellation Master Fund, Ltd ("Constellation Master Fund"), Magnetar Xing He Master Fund Ltd ("Xing He Master Fund"), Purpose Alternative Credit Fund Ltd ("Purpose Credit Fund"), Magnetar SC Fund Ltd ("SC Fund"), all Cayman Islands exempted companies; Magnetar Structured Credit Fund, LP ("Structured Credit Fund"), a Delaware limited partnership; Magnetar Alpha Star Fund LLC ("Alpha Star Fund"), Magnetar Lake Credit Fund LLC ("Lake Credit Fund"), Purpose Alternative Credit Fund - T LLC ("Purpose Credit Fund - T"), all Delaware limited liability companies; collectively (the "Magnetar Funds"). Magnetar Financial serves as the investment adviser to the Magnetar Funds, and as such, Magnetar Financial exercises voting and investment power over the Shares held for the Magnetar Funds' accounts. Magnetar Capital Partners serves as the sole member and parent holding company of Magnetar Financial. Supernova Management is the general partner of Magnetar Capital Partners. The administrative manager of Supernova Management is Mr. Snyderman. The address of the principal business office of each of Magnetar Financial, Magnetar Capital Partners, Supernova Management, and Mr. Snyderman is 1603 Orrington Avenue, 13th Floor, Evanston, Illinois 60201. Place of Organization. i) Magnetar Financial is a Delaware limited liability company; ii) Magnetar Capital Partners is a Delaware limited partnership; iii) Supernova Management is a Delaware limited liability company; and iv) Mr. Snyderman is a citizen of the United States of America. N IA HC As of September 30, 2025, each of Magnetar Financial, Magnetar Capital Partners, Supernova Management and Mr. Snyderman held 142,304 Shares. The amount consists of (A) 33,065 Shares held for the account of Constellation Master Fund; (B) 24,442 Shares held for the account of Lake Credit Fund; (C) 22,990 Shares held for the account of Structured Credit Fund; (D) 21,559 Shares held for the account of Xing He Master Fund; (E) 14,376 Shares held for the account of Alpha Star Fund; (F) 12,934 Shares held for the account of Purpose Credit Fund; (G) 10,063 Magnetar SC Fund; and (H) 2,875 Shares held for the account Purpose Credit Fund - T. The Shares held by the Magnetar Funds represent approximately 0.62% of the total number of Shares outstanding (calculated pursuant to Rule 13d-3(d)(1)(i)) of the outstanding shares of the Issuer). As of September 30, 2025, each of the Reporting Persons were deemed to be the beneficial owner constituting approximately 0.62% of the total number of shares outstanding (based upon the information provided by the Issuer in its 10-Q filed with the SEC on August 12, 2025, there were approximately 23,000,000 Shares outstanding). 0 142,304 0 142,304 N Y Y Y Y Y N By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11. 99.1 Joint Filing Agreement, dated as of November 12, 2025, among the Reporting Persons. 99.2 Power of Attorney, dated as of December 22, 2022 filed by the Reporting Persons on November 12, 2025. MAGNETAR FINANCIAL LLC /s/ Hayley Stein 11/12/2025 MAGNETAR CAPITAL PARTNERS LP /s/ Hayley Stein 11/12/2025 SUPERNOVA MANAGEMENT LLC /s/ Hayley Stein 11/12/2025 DAVID J. SNYDERMAN /s/ Hayley Stein 11/12/2025 MAGNETAR FINANCIAL LLC BY: Magnetar Capital Partners LP, its Sole Member BY: Supernova Management LLC, its General Partner MAGNETAR CAPITAL PARTNERS LP By: Supernova Management LLC, its General Partner