<SEC-DOCUMENT>0001422849-25-000078.txt : 20251113
<SEC-HEADER>0001422849-25-000078.hdr.sgml : 20251113
<ACCEPTANCE-DATETIME>20251113190613
ACCESSION NUMBER:		0001422849-25-000078
CONFORMED SUBMISSION TYPE:	SCHEDULE 13G
PUBLIC DOCUMENT COUNT:		1
FILED AS OF DATE:		20251113
DATE AS OF CHANGE:		20251113

SUBJECT COMPANY:	

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			ATI INC
		CENTRAL INDEX KEY:			0001018963
		STANDARD INDUSTRIAL CLASSIFICATION:	STEEL PIPE & TUBES [3317]
		ORGANIZATION NAME:           	04 Manufacturing
		EIN:				251792394
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1228

	FILING VALUES:
		FORM TYPE:		SCHEDULE 13G
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	005-46715
		FILM NUMBER:		251480381

	BUSINESS ADDRESS:	
		STREET 1:		2021 MCKINNEY AVENUE
		CITY:			DALLAS
		STATE:			TX
		ZIP:			75201
		BUSINESS PHONE:		4123942800

	MAIL ADDRESS:	
		STREET 1:		2021 MCKINNEY AVENUE
		CITY:			DALLAS
		STATE:			TX
		ZIP:			75201

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	ALLEGHENY TECHNOLOGIES INC
		DATE OF NAME CHANGE:	19991213

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	ALLEGHENY TELEDYNE INC
		DATE OF NAME CHANGE:	19960716

FILED BY:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Capital World Investors
		CENTRAL INDEX KEY:			0001422849
		ORGANIZATION NAME:           	
		EIN:				951411037
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0630

	FILING VALUES:
		FORM TYPE:		SCHEDULE 13G

	BUSINESS ADDRESS:	
		STREET 1:		333 SOUTH HOPE STREET
		STREET 2:		55TH FLOOR
		CITY:			LOS ANGELES
		STATE:			CA
		ZIP:			90071
		BUSINESS PHONE:		213-486-9200

	MAIL ADDRESS:	
		STREET 1:		333 SOUTH HOPE STREET
		STREET 2:		55TH FLOOR
		CITY:			LOS ANGELES
		STATE:			CA
		ZIP:			90071
</SEC-HEADER>
<DOCUMENT>
<TYPE>SCHEDULE 13G
<SEQUENCE>1
<FILENAME>primary_doc.xml
<TEXT>
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  <headerData>
    <submissionType>SCHEDULE 13G</submissionType>
    <filerInfo>
      <filer>
        <filerCredentials>
          <cik>0001422849</cik>
          <ccc>XXXXXXXX</ccc>
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      </filer>
      <liveTestFlag>LIVE</liveTestFlag>



    </filerInfo>
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  <formData>
    <coverPageHeader>
      <securitiesClassTitle>Common Stock</securitiesClassTitle>
      <eventDateRequiresFilingThisStatement>09/30/2025</eventDateRequiresFilingThisStatement>
      <issuerInfo>
        <issuerCik>0001018963</issuerCik>
        <issuerName>ATI Inc.</issuerName>
        <issuerCusip>01741R102</issuerCusip>
        <issuerPrincipalExecutiveOfficeAddress>
          <com:street1>2021 MCKINNEY AVENUE</com:street1>
          <com:city>DALLAS</com:city>
          <com:stateOrCountry>X1</com:stateOrCountry>
          <com:zipCode>75201</com:zipCode>
        </issuerPrincipalExecutiveOfficeAddress>
      </issuerInfo>
      <designateRulesPursuantThisScheduleFiled>
        <designateRulePursuantThisScheduleFiled>Rule 13d-1(b)</designateRulePursuantThisScheduleFiled>
      </designateRulesPursuantThisScheduleFiled>
    </coverPageHeader>
    <coverPageHeaderReportingPersonDetails>

      <reportingPersonName>Capital World Investors</reportingPersonName>
      <citizenshipOrOrganization>DE</citizenshipOrOrganization>
      <reportingPersonBeneficiallyOwnedNumberOfShares>
        <soleVotingPower>7909109</soleVotingPower>
        <sharedVotingPower>0</sharedVotingPower>
        <soleDispositivePower>7909109</soleDispositivePower>
        <sharedDispositivePower>0</sharedDispositivePower>
      </reportingPersonBeneficiallyOwnedNumberOfShares>
      <reportingPersonBeneficiallyOwnedAggregateNumberOfShares>7909109.00</reportingPersonBeneficiallyOwnedAggregateNumberOfShares>
      <classPercent>5.7</classPercent>
      <typeOfReportingPerson>IA</typeOfReportingPerson>
    </coverPageHeaderReportingPersonDetails>
    <items>
      <item1>
        <issuerName>ATI Inc.</issuerName>
        <issuerPrincipalExecutiveOfficeAddress>2021 MCKINNEY AVENUE, DALLAS, TX 75201</issuerPrincipalExecutiveOfficeAddress>
      </item1>
      <item2>
        <filingPersonName>Capital World Investors</filingPersonName>
        <principalBusinessOfficeOrResidenceAddress>333 SOUTH HOPE STREET, 55TH FLOOR, LOS ANGELES, CALIFORNIA  90071
</principalBusinessOfficeOrResidenceAddress>
        <citizenship>N/A</citizenship>
      </item2>
      <item3>
        <notApplicableFlag>N</notApplicableFlag>
        <typeOfPersonFiling>IA</typeOfPersonFiling>
      </item3>
      <item4>
        <amountBeneficiallyOwned>7,909,109 **

**Capital World Investors ("CWI") is a division of Capital Research and Management Company ("CRMC"), as well as its investment management subsidiaries and affiliates Capital Bank and Trust Company, Capital International, Inc., Capital International Limited, Capital International Sarl, Capital International K.K., Capital Group Private Client Services, Inc., and Capital Group Investment Management Private Limited (together with CRMC, the "investment management entities"). CWI's divisions of each of the investment management entities collectively provide investment management services under the name "Capital World Investors." CWI is deemed to be the beneficial owner of 7,909,109 shares or 5.7% of the 137,832,132 shares believed to be outstanding.</amountBeneficiallyOwned>
        <classPercent>5.7</classPercent>
        <numberOfSharesPersonHas>
          <solePowerOrDirectToVote>7,909,109</solePowerOrDirectToVote>
          <sharedPowerOrDirectToVote>0</sharedPowerOrDirectToVote>
          <solePowerOrDirectToDispose>7,909,109</solePowerOrDirectToDispose>
          <sharedPowerOrDirectToDispose>0</sharedPowerOrDirectToDispose>
        </numberOfSharesPersonHas>
      </item4>
      <item5>
        <notApplicableFlag>Y</notApplicableFlag>
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      <item6>
        <notApplicableFlag>Y</notApplicableFlag>
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        <notApplicableFlag>Y</notApplicableFlag>
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      <item9>
        <notApplicableFlag>Y</notApplicableFlag>
      </item9>
      <item10>
        <notApplicableFlag>N</notApplicableFlag>
        <certifications>By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11.</certifications>
      </item10>
    </items>
    <signatureInformation>
      <reportingPersonName>Capital World Investors</reportingPersonName>
      <signatureDetails>
        <signature>Timothy J. Moon</signature>
        <title>Vice President and Senior Counsel, Capital Research and Management Company</title>
        <date>11/13/2025</date>
      </signatureDetails>
    </signatureInformation>
  </formData>
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</SEC-DOCUMENT>
