SCHEDULE 13G 0001687509 XXXXXXXX LIVE Common Shares, no par value 06/30/2025 0001144800 TransAlta Corporation 89346D107 Suite 1400, 1100 - 1st Street S.E. Calgary A0 T2G 1B1 Rule 13d-1(b) Rubric Capital Management LP DE 0.00 15948151.00 0.00 15948151.00 15948151.00 N 5.38 IA PN David Rosen X1 0.00 15948151.00 0.00 15948151.00 15948151.00 N 5.38 HC IN TransAlta Corporation Suite 1400, 1100 - 1st Street S.E. Calgary, A0, T2G 1B1 This statement is filed by: (i) Rubric Capital Management LP ("Rubric Capital"), the investment adviser to certain investment funds and/or accounts (collectively, the "Rubric Funds") that hold the shares of common stock, no par value (the "Common Shares") of TransAlta Corporation, a Canadian corporation reported herein; and (ii) David Rosen ("Mr. Rosen"), Managing Member of Rubric Capital Management GP LLC, the general partner of Rubric Capital The foregoing persons are hereinafter sometimes collectively referred to as the "Reporting Persons." The filing of this statement should not be construed as an admission that any of the forgoing persons or any Reporting Person is, for the purposes of Section 13 of the Act, the beneficial owner of the Shares reported herein. The address of the principal business office of each of the Reporting Persons is 155 East 44th St, Suite 1630, New York, NY 10017. Rubric Capital is a Delaware limited partnership. Mr. Rosen is a citizen of the United States of America. N IA HC The information required by Item 4(a) is set forth in Row 9 of the cover page for each of the Reporting Persons and is incorporated herein by reference. The percentage set forth in Row (11) of the cover page for each of the Reporting Persons and in Item 4(b) is based on the 296,449,829 Common Shares outstanding as of May 20, 2025, as reported in Exhibit 99.1 attached to the Issuer's Report of Foreign Private Issuer on Form 6-K filed with the Securities and Exchange Commission on May 28, 2025. 5.38 The information required by Item 4(c)(i) is set forth in Row 5 of the cover page for each of the Reporting Persons and is incorporated herein by reference. The information required by Item 4(c)(ii) is set forth in Row 6 of the cover page for each of the Reporting Persons and is incorporated herein by reference. The information required by Item 4(c)(iii) is set forth in Row 7 of the cover page for each of the Reporting Persons and is incorporated herein by reference. The information required by Item 4(c)(iv) is set forth in Row 8 of the cover page for each of the Reporting Persons and is incorporated herein by reference. 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. Exhibit 99.1: Joint Filing Agreement Rubric Capital Management LP /s/ Michael Nachmani 07/09/2025 David Rosen /s/ David Rosen 07/09/2025