content: <?xml version="1.0" encoding="UTF-8"?><edgarSubmission xmlns="http://www.sec.gov/edgar/ownership" xmlns:com="http://www.sec.gov/edgar/common">
    <!-- Generated by Workiva -->
    <headerData>
      <submissionType>144</submissionType>
      <filerInfo>
        <filer>
          <filerCredentials>
            <cik>0001059374</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>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>160000</noOfUnitsSold>
        <aggregateMarketValue>12835200</aggregateMarketValue>
        <noOfUnitsOutstanding>126950448</noOfUnitsOutstanding>
        <approxSaleDate>03/03/2025</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>160000</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>12/13/2024</saleDate>
        <amountOfSecuritiesSold>94158</amountOfSecuritiesSold>
        <grossProceeds>8072061.77</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>12/16/2024</saleDate>
        <amountOfSecuritiesSold>52042</amountOfSecuritiesSold>
        <grossProceeds>4435612.52</grossProceeds>
      </securitiesSoldInPast3Months>
      <noticeSignature>
        <noticeDate>03/03/2025</noticeDate>
        <signature>J.P. Morgan Securities LLC as agent and attorney-in-fact for Alfred P West Jr</signature>
      </noticeSignature>
    </formData>
  </edgarSubmission>
metadata_documents: [{"type": "144", "sequence": "1", "filename": "primary_doc.xml", "secsgml_size_bytes": 4158}]
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
  160000
  12835200
  126950448
  03/03/2025
  Nasdaq
  Common
  11/01/2019
  Private transaction
  Issuer
  N
  160000
  11/01/2019
  n/a
  N
  Aldred P West Jr
  Care of SEI Investments Inc
  1 Freedom Valley Drive
  Oaks
  PA
  19456
  Common
  12/13/2024
  94158
  8072061.77
  Aldred P West Jr
  Care of SEI Investments Inc
  1 Freedom Valley Drive
  Oaks
  PA
  19456
  Common
  12/16/2024
  52042
  4435612.52
  03/03/2025
  J.P. Morgan Securities LLC as agent and attorney-in-fact for Alfred P West Jr