<SEC-DOCUMENT>0000350894-17-000025-index.html : 20170424
<SEC-HEADER>0000350894-17-000025.hdr.sgml : 20170424
<ACCEPTANCE-DATETIME>20170424095753
ACCESSION NUMBER:		0000350894-17-000025
CONFORMED SUBMISSION TYPE:	DEFA14A
PUBLIC DOCUMENT COUNT:		3
FILED AS OF DATE:		20170424
DATE AS OF CHANGE:		20170424
EFFECTIVENESS DATE:		20170424

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:		17777435

	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>a2017proxysupplement.htm
<DESCRIPTION>ADDITIONAL DEFINITIVE PROXY SOLICITING MATERIALS
<TEXT>
Document 1 - file: a2017proxysupplement.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>2
<FILENAME>revisedproxycardwithfreq001.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 2 - file: revisedproxycardwithfreq001.jpg

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>3
<FILENAME>revisedproxycardwithfreq002.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 3 - file: revisedproxycardwithfreq002.jpg

</DOCUMENT>
</SEC-DOCUMENT>