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      <filer>
        <filerCredentials>
          <cik>0001191733</cik>
          <ccc>XXXXXXXX</ccc>
        </filerCredentials>
      </filer>
      <liveTestFlag>LIVE</liveTestFlag>



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    <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>Wells Fargo Clearing Services</name>
        <address>
          <com:street1>1 N. Jefferson Ave</com:street1>
          <com:city>St. Louis</com:city>
          <com:stateOrCountry>MO</com:stateOrCountry>
          <com:zipCode>63103</com:zipCode>
        </address>
      </brokerOrMarketmakerDetails>
      <noOfUnitsSold>10000</noOfUnitsSold>
      <aggregateMarketValue>619728.07</aggregateMarketValue>
      <noOfUnitsOutstanding>132358055</noOfUnitsOutstanding>
      <approxSaleDate>09/20/2023</approxSaleDate>
      <securitiesExchangeName>Nasdaq</securitiesExchangeName>
    </securitiesInformation>
    <securitiesToBeSold>
      <securitiesClassTitle>Common</securitiesClassTitle>
      <acquiredDate>09/20/2023</acquiredDate>
      <natureOfAcquisitionTransaction>Stock Options</natureOfAcquisitionTransaction>
      <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
      <isGiftTransaction>N</isGiftTransaction>
      <amountOfSecuritiesAcquired>10000</amountOfSecuritiesAcquired>
      <paymentDate>09/20/2023</paymentDate>
      <natureOfPayment>Wire</natureOfPayment>
    </securitiesToBeSold>
    <nothingToReportFlagOnSecuritiesSoldInPast3Months>N</nothingToReportFlagOnSecuritiesSoldInPast3Months>
    <securitiesSoldInPast3Months>
      <sellerDetails>
        <name>Wayne Withrow</name>
        <address>
          <com:street1>1 FREEDOM VALLEY DRIVE</com:street1>
          <com:city>Oaks</com:city>
          <com:stateOrCountry>PA</com:stateOrCountry>
          <com:zipCode>19456-1100</com:zipCode>
        </address>
      </sellerDetails>
      <securitiesClassTitle>Common - SEI Investments Co.</securitiesClassTitle>
      <saleDate>07/27/2023</saleDate>
      <amountOfSecuritiesSold>10000</amountOfSecuritiesSold>
      <grossProceeds>626802.55</grossProceeds>
    </securitiesSoldInPast3Months>
    <securitiesSoldInPast3Months>
      <sellerDetails>
        <name>Wayne Withrow</name>
        <address>
          <com:street1>1 FREEDOM VALLEY DRIVE</com:street1>
          <com:city>Oaks</com:city>
          <com:stateOrCountry>PA</com:stateOrCountry>
          <com:zipCode>19456-1100</com:zipCode>
        </address>
      </sellerDetails>
      <securitiesClassTitle>Common - SEI Investments Co.</securitiesClassTitle>
      <saleDate>09/19/2023</saleDate>
      <amountOfSecuritiesSold>1076</amountOfSecuritiesSold>
      <grossProceeds>66413.95</grossProceeds>
    </securitiesSoldInPast3Months>
    <noticeSignature>
      <noticeDate>09/20/2023</noticeDate>
      <signature>Wayne M. Withrow</signature>
    </noticeSignature>
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144
0001191733
XXXXXXXX
LIVE
0000350894
SEI INVESTMENTS CO
000-10200
1 FREEDOM VALLEY DRIVE
OAKS
PA
19456-1100
6106761000
WITHROW WAYNE
Officer
Common
Wells Fargo Clearing Services
1 N. Jefferson Ave
St. Louis
MO
63103
10000
619728.07
132358055
09/20/2023
Nasdaq
Common
09/20/2023
Stock Options
Issuer
N
10000
09/20/2023
Wire
N
Wayne Withrow
1 FREEDOM VALLEY DRIVE
Oaks
PA
19456-1100
Common - SEI Investments Co.
07/27/2023
10000
626802.55
Wayne Withrow
1 FREEDOM VALLEY DRIVE
Oaks
PA
19456-1100
Common - SEI Investments Co.
09/19/2023
1076
66413.95
09/20/2023
Wayne M. Withrow