ATI executive sells 9,000 shares at $191.82

The sale was made under a Rule 10b5-1 Trading Plan dated May 21, 2026, for personal tax and estate planning purposes.

Rhea-AI Filing Summary

ATI Inc. Senior VP and CDIO Timothy J. Harris sold 9,000 shares of common stock at $191.82 per share on September 21, 2026. The sale was made under a Rule 10b5-1 Trading Plan dated May 21, 2026, for personal tax and estate planning purposes. He directly held 88,187 shares after the transaction.

Insider Trade Summary 10b5-1

Net Seller: 9,000 shares

Net Sell 1 txn

Insider Harris Timothy J

Role Senior VP and CDIO

Sold 9,000 shs ($1.73M)

Type	Security	Shares	Price	Value
Sale	Common Stock, par value $0.10 per share F1	9,000	$191.82	$1.73M

Holdings After Transaction: Common Stock, par value $0.10 per share — 88,187 shares (Direct)

Footnotes (1)

1. F1. Shares sold pursuant to a 10b5-1 Trading Plan dated May 21, 2026, entered into for personal tax and estate planning purposes.

Key Figures

Common shares sold: 9,000 shares Sale price: $191.82 per share Direct shares held after transaction: 88,187 shares

3 metrics

Common shares sold 9,000 shares September 21, 2026

Sale price $191.82 per share September 21, 2026

Direct shares held after transaction 88,187 shares Following the September 21, 2026 sale

Key Terms

Rule 10b5-1 Trading Plan, par value

2 terms

Rule 10b5-1 Trading Plan regulatory

"Shares sold pursuant to a 10b5-1 Trading Plan"

A Rule 10b5-1 trading plan is a pre-arranged schedule that allows company insiders to buy or sell stock at specific times, even if they have inside information. It helps prevent accusations of unfair trading by making these transactions look planned and transparent, rather than sneaky or illegal.

par value financial

"Common Stock, par value $0.10 per share"

Par value is the fixed amount printed on a bond or stock that represents its original value when issued. It’s like the face value of a coin or bill—what the issuer promises to pay back or the starting price of a stock—though it often doesn’t change with market prices. It matters because it helps determine certain financial details, like how much the company will pay back at maturity.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What did ATI Senior VP and CDIO Timothy J. Harris sell?

On September 21, 2026, Timothy J. Harris sold 9,000 shares of ATI common stock at $191.82 per share.

Was the ATI stock sale made under a Rule 10b5-1 plan?

Yes. The sale was made under a Rule 10b5-1 Trading Plan dated May 21, 2026, for personal tax and estate planning purposes.

How many ATI shares did Timothy J. Harris hold after the sale?

He directly held 88,187 shares after the September 21, 2026 transaction.

What is Timothy J. Harris's role at ATI?

Timothy J. Harris is ATI's Senior VP and CDIO.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 09/23/2026 - 10:32 AM Accepted by SEC EDGAR 09/23/2026 - 10:32 AM Learn about SEC filing dates

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

X

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Harris Timothy J

(Last) (First) (Middle)

C/O ATI INC.

2021 MCKINNEY AVE., SUITE 1100

(Street)

DALLAS TEXAS 75201

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
ATI INC [ ATI ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Senior VP and CDIO

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
09/21/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock, par value $0.10 per share	09/21/2026		S(1)		9,000	D	$191.82	88,187	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. Shares sold pursuant to a 10b5-1 Trading Plan dated May 21, 2026, entered into for personal tax and estate planning purposes.

	/s/ Amanda J. Skov, Attorney-in-Fact for Timothy J. Harris	09/22/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)