Report of Foreign Private Issuer

This report on Form 6-K, filed by ATS CORPORATION for the month of December 2025, serves as a Report of Foreign Private Issuer. The company indicates it will file annual reports under Form 40-F. Exhibit 99.1, a Material Change Report dated December 17, 2025, is incorporated by reference into the registrant's Registration Statements on Form F-10 and Form S-8. The report is signed by Gordon Raman, Chief Legal Officer, on behalf of ATS CORPORATION, dated December 19, 2025.