Company: TSLTF
Filing Date: 2025-12-12
Form Type: SUPPL
Source: 0001193125-25-317786
Chunk: 1

Company: TRANSALTA CORP
Filing Date: 2025-12-12
Form: SUPPL
Chunk 1
---
 right of payment to all of our future subordinated indebtedness. The Notes will be effectively subordinated to any of our future secured indebtedness to the extent of the value of the assets securing such indebtedness. None of our existing and future subsidiaries will guarantee the Notes. As a result, the Notes will be structurally subordinated to all existing and future obligations of our subsidiaries, including trade payables and indebtedness. The underwriters, as principals, conditionally offer the Notes, subject to prior sale, if, as and when issued by us and accepted by the underwriters in accordance with the conditions contained in the underwriting agreement referred to under “ Underwriting” in this Prospectus Supplement. Investing in the Notes involves risks. See “ Risk Factors ” in this Prospectus Supplement beginning on page S-22 and under the heading “ Risk Factors ” beginning on page 15 of the accompanying short form base shelf prospectus dated December 9, 2025 (the “Prospectus”). Under applicable Canadian securities legislation, we may be considered to be a “connected issuer” of RBC Capital Markets, LLC, CIBC World Markets Corp., BofA Securities, Inc., Morgan Stanley & Co. LLC, Scotia Capital (USA) Inc., BMO Capital Markets Corp., TD Securities (USA) LLC, National Bank of Canada Financial Inc., ATB Securities Inc., Desjardins Securities Inc., MUFG Securities Americas Inc., J.P. Morgan Securities LLC and Mizuho Securities USA LLC, each of which is, directly or indirectly, a subsidiary or affiliate of one of our lenders to which we are currently indebted. In addition, certain of the underwriters, or their subsidiaries or affiliates, may be holders of our 7.750% senior notes due 2029 (the “2029 Notes”). We intend to use the net proceeds from this offering, together with cash on hand, to redeem all of our outstanding 2029 Notes. In addition, affiliates of RBC Capital Markets, LLC collectively own approximately 9.5% of our issued and outstanding common shares. Accordingly, the Corporation may be considered a “related issuer” or a “connected issuer” to RBC Capital Markets, LLC for purposes of applicable Canadian securities laws. See “ Underwriting ”.

|                             |     | Per Note |        |   |     | Total |             |
| Public Offering Price(1)    |     |          | 99.385 | % |     | US$   | 397,540,000 |