X0202 SCHEDULE 13G 0001865026 XXXXXXXX LIVE Class A common stock, par value $0.0001 per share (the "Shares") 04/27/2026 0002088896 X-Energy, Inc. 98386P102 530 Gaither Road, Suite 700 Rockville MD 20850 Rule 13d-1(c) GFNCI LLC DE 0.00 16219322.00 0.00 16219322.00 16219322.00 N 5.9 OO The percentages reported in this Schedule 13G are based upon 273,442,494 Shares outstanding as of April 27, 2026 (according to the issuer's prospectus as filed with the Securities and Exchange Commission on April 27, 2026). Except as described in the preceding sentence, all Shares for the holdings of the reporting persons reported in this Schedule 13G are as of the opening of the market on May 4, 2026. XERC Holdings LLC DE 0.00 16219322.00 0.00 16219322.00 16219322.00 N 5.9 OO Citadel Advisors LLC DE 0.00 2198811.00 0.00 2198811.00 2198811.00 N 0.8 IA HC OO Citadel Advisors Holdings LP DE 0.00 2198811.00 0.00 2198811.00 2198811.00 N 0.8 HC PN Citadel GP LLC DE 0.00 2198811.00 0.00 2198811.00 2198811.00 N 0.8 HC OO Citadel Securities LLC DE 0.00 139868.00 0.00 139868.00 139868.00 N 0.1 BD OO Citadel Securities Group LP DE 0.00 139868.00 0.00 139868.00 139868.00 N 0.1 HC PN Citadel Securities GP LLC DE 0.00 139868.00 0.00 139868.00 139868.00 N 0.1 HC OO Kenneth Griffin X1 0.00 18558001.00 0.00 18558001.00 18558001.00 N 6.8 HC IN X-Energy, Inc. 530 Gaither Road, Suite 700, Rockville, MD 20850 This Schedule 13G is being jointly filed by GFNCI LLC ("GFNCI"), XERC Holdings LLC ("XERC Holdings"), Citadel Advisors LLC ("Citadel Advisors"), Citadel Advisors Holdings LP ("CAH"), Citadel GP LLC ("CGP"), Citadel Securities LLC ("Citadel Securities"), Citadel Securities Group LP ("CALC4"), Citadel Securities GP LLC ("CSGP") and Mr. Kenneth Griffin (collectively with GFNCI, XERC Holdings, Citadel Advisors, CAH, CGP, Citadel Securities, CALC4 and CSGP, the "Reporting Persons") with respect to the Shares of the above-named issuer owned by XERC Holdings, Citadel Multi-Strategy Equities Master Fund Ltd., a Cayman Islands company ("CM"), and Citadel Securities. Such owned Shares may include other instruments exercisable for or convertible into Shares. GFNCI is the sole member of XERC Holdings. Citadel Advisors is the portfolio manager for CM. CAH is the sole member of Citadel Advisors. CGP is the general partner of CAH. CALC4 is the non-member manager of Citadel Securities. CSGP is the general partner of CALC4. Mr. Griffin is the President and Chief Executive Officer of CGP, and owns a controlling interest in GFNCI, CGP and CSGP. The filing of this statement shall not be construed as an admission that any of the Reporting Persons is the beneficial owner of any securities covered by the statement other than the securities actually owned by such person (if any). The address of GFNCI and XERC Holdings is Southeast Financial Center, 200 S. Biscayne Blvd., Suite 3300, Miami, Florida 33131. The address of Citadel Advisors, CAH, CGP, Citadel Securities, CALC4, CSGP and Mr. Griffin is 830 Brickell Plaza, 15th Floor, Miami, Florida 33131. Each of GFNCI, XERC Holdings, Citadel Advisors, CGP, Citadel Securities and CSGP is organized as a limited liability company under the laws of the State of Delaware. Each of CALC4 and CAH is organized as a limited partnership under the laws of the State of Delaware. Mr. Griffin is a U.S. citizen. Y 1. GFNCI LLC may be deemed to beneficially own 16,219,322 Shares. 2. XERC Holdings LLC may be deemed to beneficially own 16,219,322 Shares. 3. Each of Citadel Advisors LLC, Citadel Advisors Holdings LP and Citadel GP LLC may be deemed to beneficially own 2,198,811 Shares. 4. Citadel Securities LLC may be deemed to beneficially own 139,868 Shares. 5. Each of Citadel Securities Group LP and Citadel Securities GP LLC may be deemed to beneficially own 139,868 Shares. 6. Mr. Griffin may be deemed to beneficially own 18,558,001 Shares. 1. The number of Shares that GFNCI LLC may be deemed to beneficially own constitutes 5.9% of the Shares outstanding. 2. The number of Shares that XERC Holdings LLC may be deemed to beneficially own constitutes 5.9% of the Shares outstanding. 3. The number of Shares that each of Citadel Advisors LLC, Citadel Advisors Holdings LP and Citadel GP LLC may be deemed to beneficially own constitutes 0.8% of the Shares outstanding. 4. The number of Shares that Citadel Securities LLC may be deemed to beneficially own constitutes 0.1% of the Shares outstanding. 5. The number of Shares that each of Citadel Securities Group LP and Citadel Securities GP LLC may be deemed to beneficially own constitutes 0.1% of the Shares outstanding. 6. The number of Shares that Mr. Griffin may be deemed to beneficially own constitutes 6.8% of the Shares outstanding. 1. GFNCI LLC: 0 2. XERC Holdings LLC: 0 3. Each of Citadel Advisors LLC, Citadel Advisors Holdings LP and Citadel GP LLC: 0 4. Citadel Securities LLC: 0 5. Each of Citadel Securities Group LP and Citadel Securities GP LLC: 0 6. Mr. Griffin: 0 1. GFNCI LLC: 16,219,322 2. XERC Holdings LLC: 16,219,322 3. Each of Citadel Advisors LLC, Citadel Advisors Holdings LP and Citadel GP LLC: 2,198,811 4. Citadel Securities LLC: 139,868 5. Each of Citadel Securities Group LP and Citadel Securities GP LLC: 139,868 6. Mr. Griffin: 18,558,001 1. GFNCI LLC: 0 2. XERC Holdings LLC: 0 3. Each of Citadel Advisors LLC, Citadel Advisors Holdings LP and Citadel GP LLC: 0 4. Citadel Securities LLC: 0 5. Each of Citadel Securities Group LP and Citadel Securities GP LLC: 0 6. Mr. Griffin: 0 1. GFNCI LLC: 16,219,322 2. XERC Holdings LLC: 16,219,322 3. Each of Citadel Advisors LLC, Citadel Advisors Holdings LP and Citadel GP LLC: 2,198,811 4. Citadel Securities LLC: 139,868 5. Each of Citadel Securities Group LP and Citadel Securities GP LLC: 139,868 6. Mr. Griffin: 18,558,001 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 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. Exhibit 99.1 - Joint Filing Agreement GFNCI LLC /s/ Gerald Beeson 05/04/2026 XERC Holdings LLC /s/ Gerald Beeson 05/04/2026 Citadel Advisors LLC /s/ Seth Levy 05/04/2026 Citadel Advisors Holdings LP /s/ Seth Levy 05/04/2026 Citadel GP LLC /s/ Seth Levy 05/04/2026 Citadel Securities LLC /s/ Seth Levy 05/04/2026 Citadel Securities Group LP /s/ Seth Levy 05/04/2026 Citadel Securities GP LLC /s/ Seth Levy 05/04/2026 Kenneth Griffin /s/ Seth Levy 05/04/2026 * Seth Levy is signing on behalf of Kenneth Griffin as attorney-in-fact pursuant to a power of attorney previously filed with the Securities and Exchange Commission, and hereby incorporated by reference herein. The power of attorney was filed as an attachment to a filing by Citadel Advisors LLC on Schedule 13G for Allakos Inc. on October 13, 2023.