<SEC-DOCUMENT>0000350894-20-000028-index.html : 20200514
<SEC-HEADER>0000350894-20-000028.hdr.sgml : 20200514
<ACCEPTANCE-DATETIME>20200514120831
ACCESSION NUMBER:		0000350894-20-000028
CONFORMED SUBMISSION TYPE:	DEFA14A
PUBLIC DOCUMENT COUNT:		3
FILED AS OF DATE:		20200514
DATE AS OF CHANGE:		20200514
EFFECTIVENESS DATE:		20200514

FILER:

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			SEI INVESTMENTS CO
		CENTRAL INDEX KEY:			0000350894
		STANDARD INDUSTRIAL CLASSIFICATION:	SECURITY BROKERS, DEALERS & FLOTATION COMPANIES [6211]
		IRS NUMBER:				231707341
		STATE OF INCORPORATION:			PA
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		DEFA14A
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-10200
		FILM NUMBER:		20876449

	BUSINESS ADDRESS:	
		STREET 1:		1 FREEDOM VALLEY DRIVE
		CITY:			OAKS
		STATE:			PA
		ZIP:			19456-1100
		BUSINESS PHONE:		6106761000

	MAIL ADDRESS:	
		STREET 1:		1 FREEDOM VALLEY DRIVE
		CITY:			OAKS
		STATE:			PA
		ZIP:			19456-1100

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	SEI INVESTMENT CO
		DATE OF NAME CHANGE:	20040806

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	SEI CORP
		DATE OF NAME CHANGE:	19920703
</SEC-HEADER>
<DOCUMENT>
<TYPE>DEFA14A
<SEQUENCE>1
<FILENAME>a2020proxysupplement.htm
<DESCRIPTION>ADDITIONAL DEFINITIVE PROXY SOLICITING MATERIALS
<TEXT>
Document 1 - file: a2020proxysupplement.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>2
<FILENAME>seiexhibit991logoa31.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 2 - file: seiexhibit991logoa31.jpg

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>3
<FILENAME>seinwnaka36.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 3 - file: seinwnaka36.jpg

</DOCUMENT>
</SEC-DOCUMENT>