Company: TSLTF
Filing Date: 2025-12-12
Form Type: SUPPL
Source: 0001193125-25-317786
Chunk: 76

Company: TRANSALTA CORP
Filing Date: 2025-12-12
Form: SUPPL
Chunk 76
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 by management. It is management’s responsibility to ensure that sound judgment, appropriate accounting principles and methods, and reasonable estimates have been used to prepare this information. They also ensure that all information presented is consistent. Management is also responsible for establishing and maintaining internal controls and procedures over the financial reporting process. The internal control system includes an internal audit function and an established business conduct policy that applies to all employees. In addition, TransAlta Corporation (TransAlta or the Company) has a Corporate Code of Conduct that applies to all employees and is signed annually and can be viewed on the Company’s website (www.transalta.com). Management believes the system of internal controls, review procedures and established policies provides reasonable assurance as to the reliability and relevance of financial reports. Management also believes that TransAlta’s operations are conducted in conformity with the law and with a high standard of business conduct. The Board of Directors (the Board) is responsible for ensuring that management fulfils its responsibilities for financial reporting and internal controls. The Board carries out its responsibilities principally through its Audit, Finance and Risk Committee (the Committee). The Committee, which consists solely of independent directors, reviews the financial statements and annual report and recommends them to the Board for approval. The Committee meets with management and internal and external auditors to discuss internal controls, auditing matters and financial reporting issues. Internal and external auditors have full and unrestricted access to the Committee. The Committee also recommends the firm of external auditors to be appointed by shareholders.

| John Kousinioris                      |     | Joel Hunter                           |
| President and Chief Executive Officer |     | Executive Vice President, Finance and |
|                                       |     | Chief Financial Officer               |
| February 19, 2025                     |     |                                       |

| F1 |     | TransAlta Corporation |     | 2024 Integrated Report |

Consolidated Financial Statements Management’s Annual Report on Internal Control Over Financial Reporting To the Shareholders of TransAlta Corporation The following report is provided by management in respect of TransAlta Corporation’s (TransAlta or the Company) internal control over financial reporting (as defined in Rules 13a-15fand 15d-15funder the United States Securities Exchange Act of 1934 and National Instrument 52-109Certification of Disclosure in Issuers’ Annual and Interim Filings (NI 51-109)). TransAlta’s management is responsible for establishing and maintaining adequate internal control over financial reporting for the Company. Management uses the Committee of Sponsoring