<SEC-DOCUMENT>0000763212-25-000010.txt : 20251113
<SEC-HEADER>0000763212-25-000010.hdr.sgml : 20251113
<ACCEPTANCE-DATETIME>20251113203207
ACCESSION NUMBER:		0000763212-25-000010
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:			MARKETAXESS HOLDINGS INC
		CENTRAL INDEX KEY:			0001278021
		STANDARD INDUSTRIAL CLASSIFICATION:	SECURITY BROKERS, DEALERS & FLOTATION COMPANIES [6211]
		ORGANIZATION NAME:           	09 Crypto Assets
		EIN:				522230784
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		SCHEDULE 13G
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	005-80409
		FILM NUMBER:		251480612

	BUSINESS ADDRESS:	
		STREET 1:		55 HUDSON YARDS, 15TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10001
		BUSINESS PHONE:		212-831-6000

	MAIL ADDRESS:	
		STREET 1:		55 HUDSON YARDS, 15TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10001

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	MARKETAXESS HOLDING INC
		DATE OF NAME CHANGE:	20040129

FILED BY:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			PRIMECAP MANAGEMENT CO/CA/
		CENTRAL INDEX KEY:			0000763212
		ORGANIZATION NAME:           	
		EIN:				953868081

	FILING VALUES:
		FORM TYPE:		SCHEDULE 13G

	BUSINESS ADDRESS:	
		STREET 1:		177 EAST COLORADO BLVD.
		STREET 2:		11TH FLOOR
		CITY:			PASADENA
		STATE:			CA
		ZIP:			91105
		BUSINESS PHONE:		6263049222

	MAIL ADDRESS:	
		STREET 1:		177 EAST COLORADO BLVD.
		STREET 2:		11TH FLOOR
		CITY:			PASADENA
		STATE:			CA
		ZIP:			91105
</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>0000763212</cik>
          <ccc>XXXXXXXX</ccc>
        </filerCredentials>
      </filer>
      <liveTestFlag>LIVE</liveTestFlag>



    </filerInfo>
  </headerData>
  <formData>
    <coverPageHeader>
      <securitiesClassTitle>COM</securitiesClassTitle>
      <eventDateRequiresFilingThisStatement>09/30/2025</eventDateRequiresFilingThisStatement>
      <issuerInfo>
        <issuerCik>0001278021</issuerCik>
        <issuerName>MarketAxess Holdings Inc.</issuerName>
        <issuerCusip>57060D108</issuerCusip>
        <issuerPrincipalExecutiveOfficeAddress>
          <ns1:street1>55 Hudson Yards</ns1:street1>
          <ns1:city>New York</ns1:city>
          <ns1:stateOrCountry>NY</ns1:stateOrCountry>
          <ns1:zipCode>10001</ns1:zipCode>
        </issuerPrincipalExecutiveOfficeAddress>
      </issuerInfo>
      <designateRulesPursuantThisScheduleFiled>
        <designateRulePursuantThisScheduleFiled>Rule 13d-1(b)</designateRulePursuantThisScheduleFiled>
      </designateRulesPursuantThisScheduleFiled>
    </coverPageHeader>
    <coverPageHeaderReportingPersonDetails>


      <reportingPersonName>PRIMECAP MANAGEMENT CO/CA/</reportingPersonName>
      <citizenshipOrOrganization>X1</citizenshipOrOrganization>
      <reportingPersonBeneficiallyOwnedNumberOfShares>
        <soleVotingPower>2224275</soleVotingPower>
        <sharedVotingPower>0</sharedVotingPower>
        <soleDispositivePower>2230595</soleDispositivePower>
        <sharedDispositivePower>0</sharedDispositivePower>
      </reportingPersonBeneficiallyOwnedNumberOfShares>
      <reportingPersonBeneficiallyOwnedAggregateNumberOfShares>2230595</reportingPersonBeneficiallyOwnedAggregateNumberOfShares>
      <aggregateAmountExcludesCertainSharesFlag>N</aggregateAmountExcludesCertainSharesFlag>
      <classPercent>5.97</classPercent>
      <typeOfReportingPerson>IA</typeOfReportingPerson>
    </coverPageHeaderReportingPersonDetails>
    <items>
      <item1>
        <issuerName>MarketAxess Holdings Inc.</issuerName>
        <issuerPrincipalExecutiveOfficeAddress>55 Hudson Yards, New York, NEW YORK
10001</issuerPrincipalExecutiveOfficeAddress>
      </item1>
      <item2>
        <filingPersonName>PRIMECAP MANAGEMENT CO/CA/</filingPersonName>
        <principalBusinessOfficeOrResidenceAddress>177 EAST COLORADO BLVD.
11TH FLOOR
PASADENA, California
91105</principalBusinessOfficeOrResidenceAddress>
        <citizenship>PRIMECAP MANAGEMENT CO/CA/ - UNITED STATES</citizenship>
      </item2>
      <item3>
        <notApplicableFlag>N</notApplicableFlag>
        <typeOfPersonFiling>IA</typeOfPersonFiling>
      </item3>
      <item4>
        <amountBeneficiallyOwned>2,230,595</amountBeneficiallyOwned>
        <classPercent>5.97</classPercent>
        <numberOfSharesPersonHas>
          <solePowerOrDirectToVote>PRIMECAP MANAGEMENT CO/CA/ - 2,224,275</solePowerOrDirectToVote>
          <sharedPowerOrDirectToVote>PRIMECAP MANAGEMENT CO/CA/ - 0</sharedPowerOrDirectToVote>
          <solePowerOrDirectToDispose>PRIMECAP MANAGEMENT CO/CA/ - 2,230,595</solePowerOrDirectToDispose>
          <sharedPowerOrDirectToDispose>PRIMECAP MANAGEMENT CO/CA/ - 0</sharedPowerOrDirectToDispose>
        </numberOfSharesPersonHas>
      </item4>
      <item5>
        <notApplicableFlag>Y</notApplicableFlag>
      </item5>
      <item6>
        <notApplicableFlag>Y</notApplicableFlag>
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      <item7>
        <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>PRIMECAP MANAGEMENT CO/CA/</reportingPersonName>
      <signatureDetails>
        <signature>Jorge A. Rodriguez</signature>
        <title>Deputy Chief Compliance Officer</title>
        <date>11/13/2025</date>
      </signatureDetails>
    </signatureInformation>
  </formData>
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</SEC-DOCUMENT>
