Company: TSLTF
Filing Date: 2025-12-12
Form Type: SUPPL
Source: 0001193125-25-317786
Chunk: 30

Company: TRANSALTA CORP
Filing Date: 2025-12-12
Form: SUPPL
Chunk 30
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 as described under “Use of Proceeds” and the payment of the underwriting commission of US$5.0 million and estimated expenses of this offering of approximately US$1.5 million. |

| (2) | Cash and cash equivalents is net of bank overdraft. |

| (3) | As of December 4, 2025, under our Syndicated Credit Facility, Bilateral Credit Facilities and Heartland                                                                
 Generation facilities, we have cumulative commitments available to be borrowed of $1.4 billion (after giving effect to $794 million of outstanding letters of credit). |

| (4) | Fair value of economic and designated hedging instruments on debt, as the carrying value of the related debt is 
 impacted by changes in foreign exchange rates.                                                                  |

| (5) | Principal portion of the TransAlta OCP LP restricted cash related to the TransAlta OCP LP bonds as this cash is 
 restricted specifically to repay outstanding debt.                                                              |

S-26

DESCRIPTION OF NOTES

The following description of the terms of the Notes supplements, and to the extent inconsistent therewith replaces, the description set forth
under the heading “Description of Debt Securities” in the Prospectus and should be read in conjunction with such description. In this section, “Corporation” refers only to TransAlta Corporation and not to any of its
subsidiaries, unless otherwise stated. All capitalized terms used under this heading “Description of Notes” that are not defined herein have the meanings ascribed thereto in the Prospectus.

General

The Notes will be issued under
an indenture dated as of June 25, 2002 between TransAlta and The Bank of New York Mellon (formerly known as The Bank of New York) as trustee (the “Trustee”), as supplemented by a supplemental indenture to be dated as of the issue
date of the Notes (as so supplemented, the “Indenture”). The Indenture is subject to, and governed by, the United StatesTrust IndentureActof1939, as amended. The
following summary of certain provisions of the Indenture and the Notes does not purport to be complete and is qualified in its entirety by reference to the actual provisions of the Indenture. A copy of the Indenture will be available on SEDAR+ at www.sedarplus.caand on EDGAR atwww.sec.gov.

The Notes will be direct unsecured obligations of the Corporation and will rank equally and ratably with