<SEC-DOCUMENT>0001422848-25-000165.txt : 20250813
<SEC-HEADER>0001422848-25-000165.hdr.sgml : 20250813
<ACCEPTANCE-DATETIME>20250813113727
ACCESSION NUMBER:		0001422848-25-000165
CONFORMED SUBMISSION TYPE:	SCHEDULE 13G/A
PUBLIC DOCUMENT COUNT:		1
FILED AS OF DATE:		20250813
DATE AS OF CHANGE:		20250813

SUBJECT COMPANY:	

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			ALLEGRO MICROSYSTEMS, INC.
		CENTRAL INDEX KEY:			0000866291
		STANDARD INDUSTRIAL CLASSIFICATION:	SEMICONDUCTORS & RELATED DEVICES [3674]
		ORGANIZATION NAME:           	04 Manufacturing
		EIN:				462405937
		FISCAL YEAR END:			0331

	FILING VALUES:
		FORM TYPE:		SCHEDULE 13G/A
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	005-92108
		FILM NUMBER:		251209768

	BUSINESS ADDRESS:	
		STREET 1:		955 PERIMETER ROAD
		CITY:			MANCHESTER
		STATE:			NH
		ZIP:			03103
		BUSINESS PHONE:		(603) 626-2300

	MAIL ADDRESS:	
		STREET 1:		955 PERIMETER ROAD
		CITY:			MANCHESTER
		STATE:			NH
		ZIP:			03103

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	ALLEGRO MICROSYSTEMS INC
		DATE OF NAME CHANGE:	19900730

FILED BY:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Capital Research Global Investors
		CENTRAL INDEX KEY:			0001422848
		ORGANIZATION NAME:           	
		EIN:				951411037
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0630

	FILING VALUES:
		FORM TYPE:		SCHEDULE 13G/A

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

	MAIL ADDRESS:	
		STREET 1:		333 SOUTH HOPE STREET
		STREET 2:		55TH FL
		CITY:			LOS ANGELES
		STATE:			CA
		ZIP:			90071
</SEC-HEADER>
<DOCUMENT>
<TYPE>SCHEDULE 13G/A
<SEQUENCE>1
<FILENAME>primary_doc.xml
<TEXT>
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    <submissionType>SCHEDULE 13G/A</submissionType>
    <previousAccessionNumber>0001422848-25-000068</previousAccessionNumber>
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      <filer>
        <filerCredentials>
          <cik>0001422848</cik>
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      <liveTestFlag>LIVE</liveTestFlag>



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  <formData>
    <coverPageHeader>
      <amendmentNo>1</amendmentNo>
      <securitiesClassTitle>Common Stock</securitiesClassTitle>
      <eventDateRequiresFilingThisStatement>06/30/2025</eventDateRequiresFilingThisStatement>
      <issuerInfo>
        <issuerCik>0000866291</issuerCik>
        <issuerName>Allegro MicroSystems, Inc.</issuerName>
        <issuerCusip>01749D105</issuerCusip>
        <issuerPrincipalExecutiveOfficeAddress>
          <com:street1>955 PERIMETER ROAD</com:street1>
          <com:city>MANCHESTER</com:city>
          <com:stateOrCountry>X1</com:stateOrCountry>
          <com:zipCode>03103</com:zipCode>
        </issuerPrincipalExecutiveOfficeAddress>
      </issuerInfo>
      <designateRulesPursuantThisScheduleFiled>
        <designateRulePursuantThisScheduleFiled>Rule 13d-1(b)</designateRulePursuantThisScheduleFiled>
      </designateRulesPursuantThisScheduleFiled>
    </coverPageHeader>
    <coverPageHeaderReportingPersonDetails>

      <reportingPersonName>Capital Research Global Investors</reportingPersonName>
      <citizenshipOrOrganization>DE</citizenshipOrOrganization>
      <reportingPersonBeneficiallyOwnedNumberOfShares>
        <soleVotingPower>15904357</soleVotingPower>
        <sharedVotingPower>0</sharedVotingPower>
        <soleDispositivePower>15904357</soleDispositivePower>
        <sharedDispositivePower>0</sharedDispositivePower>
      </reportingPersonBeneficiallyOwnedNumberOfShares>
      <reportingPersonBeneficiallyOwnedAggregateNumberOfShares>15904357.00</reportingPersonBeneficiallyOwnedAggregateNumberOfShares>
      <classPercent>8.6</classPercent>
      <typeOfReportingPerson>IA</typeOfReportingPerson>
    </coverPageHeaderReportingPersonDetails>
    <items>
      <item1>
        <issuerName>Allegro MicroSystems, Inc.</issuerName>
        <issuerPrincipalExecutiveOfficeAddress>955 PERIMETER ROAD, MANCHESTER, NH 03103</issuerPrincipalExecutiveOfficeAddress>
      </item1>
      <item2>
        <filingPersonName>Capital Research Global Investors</filingPersonName>
        <principalBusinessOfficeOrResidenceAddress>333 South Hope Street, 55th Fl, Los Angeles, CA  90071
</principalBusinessOfficeOrResidenceAddress>
        <citizenship>N/A</citizenship>
      </item2>
      <item3>
        <notApplicableFlag>N</notApplicableFlag>
        <typeOfPersonFiling>IA</typeOfPersonFiling>
      </item3>
      <item4>
        <amountBeneficiallyOwned>15,904,357 **

**Capital Research Global Investors ("CRGI") 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"). CRGI's divisions of each of the investment management entities collectively provide investment management services under the name "Capital Research Global Investors." CRGI is deemed to be the beneficial owner of 15,904,357 shares or 8.6% of the 184,925,395 shares believed to be outstanding.</amountBeneficiallyOwned>
        <classPercent>8.6</classPercent>
        <numberOfSharesPersonHas>
          <solePowerOrDirectToVote>15,904,357</solePowerOrDirectToVote>
          <sharedPowerOrDirectToVote>0</sharedPowerOrDirectToVote>
          <solePowerOrDirectToDispose>15,904,357</solePowerOrDirectToDispose>
          <sharedPowerOrDirectToDispose>0</sharedPowerOrDirectToDispose>
        </numberOfSharesPersonHas>
      </item4>
      <item5>
        <notApplicableFlag>Y</notApplicableFlag>
      </item5>
      <item6>
        <notApplicableFlag>N</notApplicableFlag>
        <ownershipMoreThan5PercentOnBehalfOfAnotherPerson>SMALLCAP World Fund, Inc.</ownershipMoreThan5PercentOnBehalfOfAnotherPerson>
      </item6>
      <item7>
        <notApplicableFlag>Y</notApplicableFlag>
      </item7>
      <item8>
        <notApplicableFlag>Y</notApplicableFlag>
      </item8>
      <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 Research Global Investors</reportingPersonName>
      <signatureDetails>
        <signature>Jae Won Chung</signature>
        <title>Vice President and Senior Counsel II, Capital Research and Management Company</title>
        <date>08/05/2025</date>
      </signatureDetails>
    </signatureInformation>
  </formData>
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</SEC-DOCUMENT>
