Michael Benjamin Miller - 05 Jan 2026 Form 4 Insider Report for ATI INC (ATI)

Role: VP Chief Accounting Officer
Signature: /s/ Amanda J. Skov, Attorney-in-Fact for Michael B. Miller
Issuer symbol: ATI
Transactions as of: 05 Jan 2026
Net transactions value: -$45,284
Form type: 4
Filing time: 07 Jan 2026, 17:23:08 UTC
Previous filing: 09 Dec 2025
Next filing: 03 Mar 2026
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Miller Michael Benjamin	VP Chief Accounting Officer	C/O ATI INC., 2021 MCKINNEY AVENUE, SUITE 1100, DALLAS	/s/ Amanda J. Skov, Attorney-in-Fact for Michael B. Miller	07 Jan 2026	0001880164

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	ATI	Common Stock, par value $0.10 per share	Award	$0	+854	+11%	$0.000000	8,426	05 Jan 2026	Direct	F1, F2
transaction	ATI	Common Stock, par value $0.10 per share	Tax liability	$45,284	-374	-4.4%	$121.08	8,052	05 Jan 2026	Direct	F3, F4

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	Award of restricted stock units, which are settled in shares of stock upon vesting. The award vests in three equal annual installments on each of the first three anniversaries of the grant date.
F2	Awarded under the Issuer's 2022 Incentive Plan.
F3	Shares withheld for the payment of taxes on restricted stock units awarded in 2024 and 2025. One-third of each such award vested by the terms thereof on January 5, 2026.
F4	Represents the average of the high and low trading prices for one share of the Issuer's Common Stock on the New York Stock Exchange on January 5, 2026.