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        <filer>
          <filerCredentials>
            <cik>0001059374</cik>
            <ccc>XXXXXXXX</ccc>
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        <liveTestFlag>LIVE</liveTestFlag>
  
  
  
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      <issuerInfo>
        <issuerCik>0000350894</issuerCik>
        <issuerName>SEI Investments Company</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</com:zipCode>
        </issuerAddress>
        <issuerContactPhone>610-676-1000</issuerContactPhone>
        <nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>Alfred P.  West,  Jr.</nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>
        <relationshipsToIssuer>
          <relationshipToIssuer>Executive Chairman</relationshipToIssuer>
        </relationshipsToIssuer>
      </issuerInfo>
      <securitiesInformation>
        <securitiesClassTitle>Common Stock</securitiesClassTitle>
        <brokerOrMarketmakerDetails>
          <name>J.P. Morgan Securities LLC</name>
          <address>
            <com:street1>390 Madison Avenue, 6th Floor</com:street1>
            <com:city>New York</com:city>
            <com:stateOrCountry>NY</com:stateOrCountry>
            <com:zipCode>10017</com:zipCode>
          </address>
        </brokerOrMarketmakerDetails>
        <noOfUnitsSold>151000</noOfUnitsSold>
        <aggregateMarketValue>12981470</aggregateMarketValue>
        <noOfUnitsOutstanding>124486658</noOfUnitsOutstanding>
        <approxSaleDate>05/28/2025</approxSaleDate>
        <securitiesExchangeName>NASDAQ</securitiesExchangeName>
      </securitiesInformation>
      <securitiesToBeSold>
        <securitiesClassTitle>Common Stock</securitiesClassTitle>
        <acquiredDate>11/01/2019</acquiredDate>
        <natureOfAcquisitionTransaction>Private Transaction</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>151000</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>C/o SEI Investments Company</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 Stock</securitiesClassTitle>
        <saleDate>03/04/2025</saleDate>
        <amountOfSecuritiesSold>1372</amountOfSecuritiesSold>
        <grossProceeds>104584</grossProceeds>
      </securitiesSoldInPast3Months>
      <securitiesSoldInPast3Months>
        <sellerDetails>
          <name>Aldred P. West, Jr.</name>
          <address>
            <com:street1>C/o SEI Investments Company</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 Stock</securitiesClassTitle>
        <saleDate>03/05/2025</saleDate>
        <amountOfSecuritiesSold>80000</amountOfSecuritiesSold>
        <grossProceeds>6111614</grossProceeds>
      </securitiesSoldInPast3Months>
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          <name>Aldred P. West, Jr.</name>
          <address>
            <com:street1>C/o SEI Investments Company</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 Stock</securitiesClassTitle>
        <saleDate>03/06/2025</saleDate>
        <amountOfSecuritiesSold>72842</amountOfSecuritiesSold>
        <grossProceeds>5783829</grossProceeds>
      </securitiesSoldInPast3Months>
      <noticeSignature>
        <noticeDate>05/28/2025</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 Company
  000-10200
  1 Freedom Valley Drive
  Oaks
  PA
  19456
  610-676-1000
  Alfred P.  West,  Jr.
  Executive Chairman
  Common Stock
  J.P. Morgan Securities LLC
  390 Madison Avenue, 6th Floor
  New York
  NY
  10017
  151000
  12981470
  124486658
  05/28/2025
  NASDAQ
  Common Stock
  11/01/2019
  Private Transaction
  Issuer
  N
  151000
  11/01/2019
  N/A
  N
  Aldred P. West, Jr.
  C/o SEI Investments Company
  1 Freedom Valley Drive
  Oaks
  PA
  19456
  Common Stock
  03/04/2025
  1372
  104584
  Aldred P. West, Jr.
  C/o SEI Investments Company
  1 Freedom Valley Drive
  Oaks
  PA
  19456
  Common Stock
  03/05/2025
  80000
  6111614
  Aldred P. West, Jr.
  C/o SEI Investments Company
  1 Freedom Valley Drive
  Oaks
  PA
  19456
  Common Stock
  03/06/2025
  72842
  5783829
  05/28/2025
  J.P. Morgan Securities LLC as agent and attorney-in-fact for Alfred P. West, Jr.