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      <filerInfo>
        <filer>
          <filerCredentials>
            <cik>0001059374</cik>
            <ccc>XXXXXXXX</ccc>
          </filerCredentials>
        </filer>
        <liveTestFlag>LIVE</liveTestFlag>
  
  
  
      </filerInfo>
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      <issuerInfo>
        <issuerCik>0000350894</issuerCik>
        <issuerName>SEI Investments Co</issuerName>
        <secFileNumber>000-10200</secFileNumber>
        <issuerAddress>
          <com:street1>One Freedom Valley Drive</com:street1>
          <com:city>Oaks</com:city>
          <com:stateOrCountry>PA</com:stateOrCountry>
          <com:zipCode>19456-100</com:zipCode>
        </issuerAddress>
        <issuerContactPhone>610-676-1000</issuerContactPhone>
        <nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>Alfred Paul West Jr</nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>
        <relationshipsToIssuer>
          <relationshipToIssuer>Affiliate</relationshipToIssuer>
        </relationshipsToIssuer>
      </issuerInfo>
      <securitiesInformation>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <brokerOrMarketmakerDetails>
          <name>J.P. Morgan Securities LLC</name>
          <address>
            <com:street1>390 Madison Avenue</com:street1>
            <com:street2>6th Floor</com:street2>
            <com:city>New York</com:city>
            <com:stateOrCountry>NY</com:stateOrCountry>
            <com:zipCode>10017</com:zipCode>
          </address>
        </brokerOrMarketmakerDetails>
        <noOfUnitsSold>155000</noOfUnitsSold>
        <aggregateMarketValue>12404650</aggregateMarketValue>
        <noOfUnitsOutstanding>128908648</noOfUnitsOutstanding>
        <approxSaleDate>11/07/2024</approxSaleDate>
        <securitiesExchangeName>Nasdaq</securitiesExchangeName>
      </securitiesInformation>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>11/01/2019</acquiredDate>
        <natureOfAcquisitionTransaction>Private transaction</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>155000</amountOfSecuritiesAcquired>
        <paymentDate>11/01/2019</paymentDate>
        <natureOfPayment>n/a</natureOfPayment>
      </securitiesToBeSold>
      <nothingToReportFlagOnSecuritiesSoldInPast3Months>N</nothingToReportFlagOnSecuritiesSoldInPast3Months>
      <securitiesSoldInPast3Months>
        <sellerDetails>
          <name>Aldred P West Jr</name>
          <address>
            <com:street1>Care of SEI Investments Inc</com:street1>
            <com:street2>1 Freedom Valley Drive</com:street2>
            <com:city>Oaks</com:city>
            <com:stateOrCountry>PA</com:stateOrCountry>
            <com:zipCode>19456</com:zipCode>
          </address>
        </sellerDetails>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <saleDate>08/29/2024</saleDate>
        <amountOfSecuritiesSold>5670</amountOfSecuritiesSold>
        <grossProceeds>382726.13</grossProceeds>
      </securitiesSoldInPast3Months>
      <securitiesSoldInPast3Months>
        <sellerDetails>
          <name>Aldred P West Jr</name>
          <address>
            <com:street1>Care of SEI Investments Inc</com:street1>
            <com:street2>1 Freedom Valley Drive</com:street2>
            <com:city>Oaks</com:city>
            <com:stateOrCountry>PA</com:stateOrCountry>
            <com:zipCode>19456</com:zipCode>
          </address>
        </sellerDetails>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <saleDate>08/28/2024</saleDate>
        <amountOfSecuritiesSold>61000</amountOfSecuritiesSold>
        <grossProceeds>4108746.5</grossProceeds>
      </securitiesSoldInPast3Months>
      <securitiesSoldInPast3Months>
        <sellerDetails>
          <name>Aldred P West Jr</name>
          <address>
            <com:street1>Care of SEI Investments Inc</com:street1>
            <com:street2>1 Freedom Valley Drive</com:street2>
            <com:city>Oaks</com:city>
            <com:stateOrCountry>PA</com:stateOrCountry>
            <com:zipCode>19456</com:zipCode>
          </address>
        </sellerDetails>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <saleDate>08/27/2024</saleDate>
        <amountOfSecuritiesSold>40129</amountOfSecuritiesSold>
        <grossProceeds>2684445.51</grossProceeds>
      </securitiesSoldInPast3Months>
      <securitiesSoldInPast3Months>
        <sellerDetails>
          <name>Aldred P West Jr</name>
          <address>
            <com:street1>Care of SEI Investments Inc</com:street1>
            <com:street2>1 Freedom Valley Drive</com:street2>
            <com:city>Oaks</com:city>
            <com:stateOrCountry>PA</com:stateOrCountry>
            <com:zipCode>19456</com:zipCode>
          </address>
        </sellerDetails>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <saleDate>08/26/2024</saleDate>
        <amountOfSecuritiesSold>44163</amountOfSecuritiesSold>
        <grossProceeds>2983109.08</grossProceeds>
      </securitiesSoldInPast3Months>
      <securitiesSoldInPast3Months>
        <sellerDetails>
          <name>Aldred P West Jr</name>
          <address>
            <com:street1>Care of SEI Investments Inc</com:street1>
            <com:street2>1 Freedom Valley Drive</com:street2>
            <com:city>Oaks</com:city>
            <com:stateOrCountry>PA</com:stateOrCountry>
            <com:zipCode>19456</com:zipCode>
          </address>
        </sellerDetails>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <saleDate>08/23/2024</saleDate>
        <amountOfSecuritiesSold>27419</amountOfSecuritiesSold>
        <grossProceeds>1850253.31</grossProceeds>
      </securitiesSoldInPast3Months>
      <noticeSignature>
        <noticeDate>11/07/2024</noticeDate>
        <signature>J.P. Morgan Securities LLC as agent and attorney-in-fact for Alfred P West Jr</signature>
      </noticeSignature>
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text: 144
  0001059374
  XXXXXXXX
  LIVE
  0000350894
  SEI Investments Co
  000-10200
  One Freedom Valley Drive
  Oaks
  PA
  19456-100
  610-676-1000
  Alfred Paul West Jr
  Affiliate
  Common
  J.P. Morgan Securities LLC
  390 Madison Avenue
  6th Floor
  New York
  NY
  10017
  155000
  12404650
  128908648
  11/07/2024
  Nasdaq
  Common
  11/01/2019
  Private transaction
  Issuer
  N
  155000
  11/01/2019
  n/a
  N
  Aldred P West Jr
  Care of SEI Investments Inc
  1 Freedom Valley Drive
  Oaks
  PA
  19456
  Common
  08/29/2024
  5670
  382726.13
  Aldred P West Jr
  Care of SEI Investments Inc
  1 Freedom Valley Drive
  Oaks
  PA
  19456
  Common
  08/28/2024
  61000
  4108746.5
  Aldred P West Jr
  Care of SEI Investments Inc
  1 Freedom Valley Drive
  Oaks
  PA
  19456
  Common
  08/27/2024
  40129
  2684445.51
  Aldred P West Jr
  Care of SEI Investments Inc
  1 Freedom Valley Drive
  Oaks
  PA
  19456
  Common
  08/26/2024
  44163
  2983109.08
  Aldred P West Jr
  Care of SEI Investments Inc
  1 Freedom Valley Drive
  Oaks
  PA
  19456
  Common
  08/23/2024
  27419
  1850253.31
  11/07/2024
  J.P. Morgan Securities LLC as agent and attorney-in-fact for Alfred P West Jr