content: <?xml version="1.0" encoding="UTF-8"?><edgarSubmission xmlns="http://www.sec.gov/edgar/ownership" xmlns:com="http://www.sec.gov/edgar/common">
    <headerData>
      <submissionType>144</submissionType>
      <filerInfo>
        <filer>
          <filerCredentials>
            <cik>0001191733</cik>
            <ccc>XXXXXXXX</ccc>
          </filerCredentials>
        </filer>
        <liveTestFlag>LIVE</liveTestFlag>
  
  
  
      </filerInfo>
    </headerData>
    <formData>
      <issuerInfo>
        <issuerCik>0000350894</issuerCik>
        <issuerName>SEI INVESTMENTS CO</issuerName>
        <secFileNumber>000-10200</secFileNumber>
        <issuerAddress>
          <com:street1>1 FREEDOM VALLEY DRIVE</com:street1>
          <com:city>OAKS</com:city>
          <com:stateOrCountry>PA</com:stateOrCountry>
          <com:zipCode>19456-1100</com:zipCode>
        </issuerAddress>
        <issuerContactPhone>6106761000</issuerContactPhone>
        <nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>WITHROW WAYNE</nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>
        <relationshipsToIssuer>
          <relationshipToIssuer>Officer</relationshipToIssuer>
        </relationshipsToIssuer>
      </issuerInfo>
      <securitiesInformation>
        <securitiesClassTitle>COMMON</securitiesClassTitle>
        <brokerOrMarketmakerDetails>
          <name>RBC WEALTH MANAGEMENT</name>
          <address>
            <com:street1>250 NICOLLET MALL, SUITE 1700</com:street1>
            <com:city>MINNEAPOLIS</com:city>
            <com:stateOrCountry>MN</com:stateOrCountry>
            <com:zipCode>55401</com:zipCode>
          </address>
        </brokerOrMarketmakerDetails>
        <noOfUnitsSold>15000</noOfUnitsSold>
        <aggregateMarketValue>993028.00</aggregateMarketValue>
        <noOfUnitsOutstanding>131587693</noOfUnitsOutstanding>
        <approxSaleDate>02/07/2024</approxSaleDate>
        <securitiesExchangeName>NASDAQ</securitiesExchangeName>
      </securitiesInformation>
      <securitiesToBeSold>
        <securitiesClassTitle>COMMON</securitiesClassTitle>
        <acquiredDate>12/08/2015</acquiredDate>
        <natureOfAcquisitionTransaction>OPTION EXERCISE</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>ISSUER</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>15000</amountOfSecuritiesAcquired>
        <paymentDate>12/08/2015</paymentDate>
        <natureOfPayment>N/A</natureOfPayment>
      </securitiesToBeSold>
      <nothingToReportFlagOnSecuritiesSoldInPast3Months>Y</nothingToReportFlagOnSecuritiesSoldInPast3Months>
      <noticeSignature>
        <noticeDate>02/07/2024</noticeDate>
        <signature>JEFFREY EISCHENS</signature>
      </noticeSignature>
    </formData>
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text: 144
  0001191733
  XXXXXXXX
  LIVE
  0000350894
  SEI INVESTMENTS CO
  000-10200
  1 FREEDOM VALLEY DRIVE
  OAKS
  PA
  19456-1100
  6106761000
  WITHROW WAYNE
  Officer
  COMMON
  RBC WEALTH MANAGEMENT
  250 NICOLLET MALL, SUITE 1700
  MINNEAPOLIS
  MN
  55401
  15000
  993028.00
  131587693
  02/07/2024
  NASDAQ
  COMMON
  12/08/2015
  OPTION EXERCISE
  ISSUER
  N
  15000
  12/08/2015
  N/A
  Y
  02/07/2024
  JEFFREY EISCHENS