Results of Operations and Financial Condition. On August 6, 2026, ATI Inc. ("the Company") issued a press release (the "Earnings Press Release") announcing its financial results for the second quarter 2026. The text of the Press Release is included as Exhibit 99.1 to this Current Report on Form 8-K. The information disclosed under this Item 2.02, including Exhibit 99.1 hereto, is being furnished and shall not be deemed "filed" for purposes of Section 18 of the Securities Exchange Act of 1934…

Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant The disclosure set forth above under

Entry into a Material Definitive Agreement On June 8, 2026, ATI Inc. (the “Company”) completed its offering and sale of $450 million aggregate principal amount of the Company’s unsecured 5.875% Senior Notes due 2033 (the “Notes”). The offering and sale of the Notes (the “Offering”) were made pursuant to the Company’s shelf registration statement filed with the Securities and Exchange Commission. The Notes were issued pursuant to the Indenture, dated as of September 14, 2021 (the “Indenture”),…

Other Events. On June 3, 2026, ATI Inc. (the “Company”) announced the pricing of its offering of unsecured 5.875% Senior Notes due 2033 (the “Notes”). The Company’s press release announcing the pricing of its offering of the Notes is set forth in its entirety and filed as Exhibit 99.1 to this Current Report on Form 8-K and is incorporated herein by reference.

Results of Operations and Financial Condition. On April 30, 2026, ATI Inc. ("the Company") issued a press release (the "Earnings Press Release") announcing its financial results for the first quarter 2026. The text of the Press Release is included as Exhibit 99.1 to this Current Report on Form 8-K. The information disclosed under this Item 2.02, including Exhibit 99.1 hereto, is being furnished and shall not be deemed "filed" for purposes of Section 18 of the Securities Exchange Act of 1934 a…

Other Events. On February 18, 2026, the Board of Directors (the “Board”) of ATI Inc. (the “Company”) authorized the additional repurchase of up to $500 million of its outstanding common stock, which the Company currently expects will support a multi-year share repurchase program in combination with the currently remaining $120 million from its prior authorization. Repurchases under the program may be made in the open market or in privately negotiated transactions, with the amount and timing o…

Results of Operations and Financial Condition. On February 3, 2026, ATI Inc. ("the Company") issued a press release (the "Earnings Press Release") announcing its financial results for the fourth quarter 2025. The text of the Press Release is included as Exhibit 99.1 to this Current Report on Form 8-K. The information disclosed under this Item 2.02, including Exhibit 99.1 hereto, is being furnished and shall not be deemed "filed" for purposes of Section 18 of the Securities Exchange Act of 193…

CFO — Donald P. Newman: The CFO is retiring with a named internal successor (J. Robert Foster) and a transition plan, representing an orderly succession rather than a sudden loss of leadership.

Executive Chairman — Robert S. Wetherbee: The filing announces the planned retirement of the Executive Chairman with a named successor (the CEO) taking over the role, indicating an orderly succession rather than a sudden loss of leadership.

Results of Operations and Financial Condition. On October 28, 2025, ATI Inc. ("the Company") issued a press release (the "Earnings Press Release") announcing its financial results for the third quarter 2025. The text of the Press Release is included as Exhibit 99.1 to this Current Report on Form 8-K. The information disclosed under this Item 2.02, including Exhibit 99.1 hereto, is being furnished and shall not be deemed "filed" for purposes of Section 18 of the Securities Exchange Act of 1934…

Entry into a Material Definitive Agreement. On September 19, 2025, ATI Specialty Materials, LLC (the “Company”), an indirect wholly-owned subsidiary of ATI Inc. (“ATI”), entered into a three-year, $125 million accounts receivable securitization facility (the “Facility”) pursuant to (i) a First Tier Purchase and Sale Agreement (the “First Tier Agreement”) among the Company, as Servicer and as the Originator, and ATI Securitization Holdings LLC, a bankruptcy-remote special purpose entity that i…

Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant. The disclosure set forth in

CFO — Donald P. Newman: The CFO is retiring with a planned transition period and consulting arrangement, representing an orderly succession rather than a sudden loss.

Results of Operations and Financial Condition. On July 31, 2025, ATI Inc. ("the Company") issued a press release (the "Earnings Press Release") announcing its financial results for the second quarter 2025. The text of the Press Release is included as Exhibit 99.1 to this Current Report on Form 8-K. The information disclosed under this Item 2.02, including Exhibit 99.1 hereto, is being furnished and shall not be deemed "filed" for purposes of Section 18 of the Securities Exchange Act of 1934 a…

SIGNATURE Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized. ATI Inc. By: /s/ Vaishali S. Bhatia Vaishali S. Bhatia Senior Vice President, General Counsel and Chief Compliance Officer Dated: June 20, 2025

Entry into a Material Definitive Agreement. On June 13, 2025, ATI Inc. (the “Company”) and certain wholly-owned domestic subsidiaries of the Company entered into that certain Second Amended and Restated Revolving Credit, Term Loan, Delayed Draw Term Loan and Security Agreement by and among the subsidiary borrowers party thereto (collectively, the “Borrowers”), the Company and other subsidiary guarantors party thereto (collectively, the “Guarantors” and together with the Borrowers, the “Loan P…

Results of Operations and Financial Condition. On May 1, 2025, ATI Inc. ("the Company") issued a press release (the "Earnings Press Release") announcing its financial results for the first quarter 2025. The text of the Press Release is included as Exhibit 99.1 to this Current Report on Form 8-K. The information disclosed under this Item 2.02, including Exhibit 99.1 hereto, is being furnished and shall not be deemed "filed" for purposes of Section 18 of the Securities Exchange Act of 1934 and…

Results of Operations and Financial Condition. On February 4, 2025, ATI Inc. ("the Company") issued a press release (the "Earnings Press Release") announcing its financial results for the fourth quarter 2024. The text of the Press Release is included as Exhibit 99.1 to this Current Report on Form 8-K. The information disclosed under this Item 2.02, including Exhibit 99.1 hereto, is being furnished and shall not be deemed "filed" for purposes of Section 18 of the Securities Exchange Act of 193…

Results of Operations and Financial Condition. On October 29, 2024, ATI Inc. ("the Company") issued a press release (the "Earnings Press Release") announcing its financial results for the third quarter 2024. The text of the Press Release is included as Exhibit 99.1 to this Current Report on Form 8-K. The information disclosed under this Item 2.02, including Exhibit 99.1 hereto, is being furnished and shall not be deemed "filed" for purposes of Section 18 of the Securities Exchange Act of 1934…

Results of Operations and Financial Condition. On August 6, 2024, ATI Inc. ("the Company") issued a press release (the "Earnings Press Release") announcing its financial results for the second quarter 2024. The text of the Press Release is included as Exhibit 99.1 to this Current Report on Form 8-K. The information disclosed under this Item 2.02, including Exhibit 99.1 hereto, is being furnished and shall not be deemed "filed" for purposes of Section 18 of the Securities Exchange Act of 1934…

Results of Operations and Financial Condition. On April 30, 2024, ATI Inc. ("the Company") issued a press release (the "Earnings Press Release") announcing its financial results for the first quarter 2024. The text of the Press Release is included as Exhibit 99.1 to this Current Report on Form 8-K. The information disclosed under this Item 2.02, including Exhibit 99.1 hereto, is being furnished and shall not be deemed "filed" for purposes of Section 18 of the Securities Exchange Act of 1934 a…

Chief Accounting Officer — Michael B. Miller: The filing announces the appointment of an external candidate to the role of Vice President, Corporate Controller and Chief Accounting Officer, which is a new hire rather than a departure.