Investor Contact:                         Media Contact:

Murray Louis                            Dana Grosser

SEI    SEI

+1 610-676-1932                        +1 610-676-2459

mlouis@seic.com                         dgrosser@seic.com

Pages:        9

FOR IMMEDIATE RELEASE

SEI REPORTS THIRD-QUARTER 2012 FINANCIAL RESULTS

Strong Sales Results Continue

OAKS, Pa., October 24, 2012 -- SEI Investments Company (NASDAQ:SEIC) today announced financial results for third-quarter 2012. Diluted earnings per share were $.29 in third-quarter 2012 compared to $.27 in third-quarter 2011.

Consolidated Overview		For the Three Months											For the Nine Months
(In thousands, except earnings per share)		Ended September 30,											Ended September 30,
		2012				2011				%			2012				2011				%
Revenues		$	251,752			$	233,227			8	%		730,887				703,480				4	%
Net Income attributable to SEI		50,743				49,232				3	%		150,263				160,563				(6	)%
Diluted Earnings Per Share			$0.29				$0.27			7	%			$0.85				$0.86			(1	)%

“Continued strong new business sales and growing revenue are the highlights of the third-quarter 2012,” said Alfred P. West, Jr., SEI Chairman and CEO.

“We continue to see growing acceptance of our solutions and services in all markets. We remain confident that the investments we have made and continue to make will significantly enhance long-term shareholder value.”

---

Summary of Third-Quarter Results by Business Segment

(In thousands)		For the Three Months											For the Nine Months
		Ended September 30,											Ended September 30,
		2012				2011				%			2012				2011				%
Private Banks:
Revenues			$92,076				$87,697			5	%			$268,367				$262,279			2	%
Expenses		91,209				85,893				6	%		263,612				254,570				4	%
Operating Profit			$867				$1,804			(52	)%			$4,755				$7,709			(38	)%
Operating Margin		1		%		2		%					2		%		3		%
Investment Advisors:
Revenues		51,384				46,798				10	%		150,227				144,674				4	%
Expenses		30,114				28,051				7	%		88,440				82,825				7	%
Operating Profit		21,270				18,747				13	%		61,787				61,849				—	%
Operating Margin		41		%		40		%					41		%		43		%
Institutional Investors:
Revenues		58,081				52,216				11	%		167,293				160,132				4	%
Expenses		29,654				25,524				16	%		86,494				79,883				8	%
Operating Profit		28,427				26,692				7	%		80,799				80,249				1	%
Operating Margin		49		%		51		%					48		%		50		%
Investment Managers:
Revenues		49,311				45,585				8	%		142,235				133,478				7	%
Expenses		32,122				29,412				9	%		92,711				86,693				7	%
Operating Profit		17,189				16,173				6	%		49,524				46,785				6	%
Operating Margin		35		%		35		%					35		%		35		%
Investments in New Businesses:
Revenues		900				931				(3	)%		2,765				2,917				(5	)%
Expenses		3,698				2,429				52	%		11,080				8,474				31	%
Operating Loss		(2,798		)		(1,498		)		N/A			(8,315		)		(5,557		)		N/A
Operating Margin		N/A				N/A							N/A				N/A
Totals:
Revenues			$251,752				$233,227			8	%			$730,887				$703,480			4	%
Expenses		186,797				171,309				9	%		542,337				512,445				6	%
Corporate overhead expenses		11,668				11,155				5	%		33,830				32,523				4	%
Noncontrolling interest reflected in segments		(203		)		(373		)		N/A			(657		)		(1,178		)		N/A
Income from operations			$53,490				$51,136			5	%			$155,377				$159,690			(3	)%

#PageNum#

---

Third-Quarter Business Commentary:

•	Revenues increased in third-quarter 2012 as compared to both third-quarter 2011 and second-quarter 2012. This was driven by an increase in Asset management, administration, and distribution fee revenues resulting from increased cash flows from new and existing clients and market appreciation in 2012.

•	Our average assets under management, excluding LSV, increased $14.8 billion, or 13 percent, to $132.6 billion in the third-quarter 2012, as compared to $117.8 billion during the third-quarter 2011, and increased $6.0 billion, or five percent, as compared to $126.6 billion during the second-quarter 2012 (See attached Ending and Average Asset Balances schedules for further details).

•	Sales events, net of client losses, during third-quarter 2012 totaled approximately $23.7 million and are expected to generate net annualized recurring revenues of approximately $21.4 million when contract values are fully realized.

•	Income from LSV increased in third-quarter 2012 to $24.9 million as compared to third-quarter 2011 and second-quarter 2012 due to an increase in assets under management. Our ownership interest was 40 percent in second- and third-quarter 2012 and 41 percent in third-quarter 2011.

•

In the third-quarter 2012, SEI decided to discontinue the use of specific functionality within the Global Wealth Platform and incurred $2.7 million of amortization expense related to the remaining net book value of this component. This expense was recognized in the Private Banks segment. Without this expense Private Banks profits for the quarter would have been $3.5 million, which is comparable to second-quarter 2012.

•	Net income attributable to SEI includes gains from SIV securities of $3.4 million in third-quarter 2012 compared to losses of $0.8 million in third-quarter 2011 and a gain of $1.1 million in second-quarter 2012.

•

The effective tax rates were 39.0 percent in the third-quarter 2012 and 33.8 percent in the third-quarter 2011. The increase in the tax rate was due to the accrual of taxes on the cumulative undistributed earnings of SEI Asset Korea, offset by certain tax planning strategies which benefited the tax rate in third-quarter 2011. As a result of the sale of SEI Asset Korea, the Company no longer considers the undistributed earnings to be indefinitely reinvested and therefore accrued U.S. deferred taxes on the cumulative undistributed earnings of SEI Asset Korea.

•	In the third-quarter 2012, SEI purchased 1.55 million shares of its common stock for $33.6 million.

#PageNum#

---

Earnings Conference Call

A conference call to review earnings is scheduled for 2:00 PM ET on October 24, 2012. Investors may listen to the call at www.seic.com/investors or listen at www.earnings.com, a service of Thomson Streetevents. The call may also be accessed at numerous financial services web sites including AOL and Yahoo. Investors may also listen to replays at these web sites, or by telephone at (USA) 1-800-475-6701; (International) 320-365-3844, access code 268471.

About SEI

SEI (NASDAQ:SEIC) is a leading global provider of investment processing, fund processing, and investment management business outsourcing solutions that help corporations, financial institutions, financial advisors, and ultra-high-net-worth families create and manage wealth. As of September 30, 2012, through its subsidiaries and partnerships in which the company has a significant interest, SEI manages or administers $448 billion in mutual fund and pooled or separately managed assets, including $195 billion in assets under management and $253 billion in client assets under administration. For more information, visit www.seic.com.

Many of the statements in this release may be considered “forward looking statements” and include discussions about future operations, strategies and financial results. Forward-looking statements are based upon estimates and assumptions that involve risks and uncertainties, many of which are beyond our control or are subject to change. Although we believe our assumptions are reasonable, they could be inaccurate. Our actual future revenues and income could differ materially from our expected results. We have no obligation to publicly update or revise any forward-looking statements.

#PageNum#

---

SEI INVESTMENTS COMPANY

CONSOLIDATED STATEMENTS OF OPERATIONS

(In thousands, except per share data)

(Unaudited)

		For the Three Months Ended September 30,
		2012				2011
Asset management, admin. and distribution fees			$183,083				$167,827
Information processing and software servicing fees		60,901				55,676
Transaction–based and trade execution fees		7,768				9,724
Total revenues		251,752				233,227
Subadvisory, distribution and other asset mgmt costs		26,538				24,613
Software royalties and other information processing costs		6,185				6,703
Brokerage commissions		5,542				7,026
Compensation, benefits and other personnel		85,781				71,198
Stock-based compensation		3,879				3,424
Consulting, outsourcing and professional fees		27,314				30,183
Data processing and computer related		11,749				12,316
Facilities, supplies and other costs		15,129				14,274
Amortization		10,384				7,008
Depreciation		5,761				5,346
Total expenses		198,262				182,091
Income from operations		53,490				51,136
Net gain (loss) on investments		3,708				(1,418		)
Interest and dividend income		1,490				1,400
Interest expense		(115		)		(126		)
Equity in earnings of unconsolidated affiliate		24,928				23,908
Net income before income taxes		83,501				74,900
Income taxes		32,415				25,256
Net income		51,086				49,644
Less: Net income attributable to the noncontrolling interest		(343		)		(412		)
Net income attributable to SEI			$50,743				$49,232
Diluted earnings per common share			$0.29				$0.27
Shares used to calculate diluted earnings per share		175,369				182,580
Basic earnings per common share			$0.29				$0.27
Shares used to calculate basic earnings per share		173,429				181,718

#PageNum#

---

SEI INVESTMENTS COMPANY

CONSOLIDATED STATEMENTS OF OPERATIONS

(In thousands, except per share data)

(Unaudited)

		For the Nine Months Ended September 30,
		2012				2011
Asset management, admin. and distribution fees			$532,650				$507,662
Information processing and software servicing fees		174,355				167,535
Transaction–based and trade execution fees		23,882				28,283
Total revenues		730,887				703,480
Subadvisory, distribution and other asset mgmt costs		80,889				77,213
Software royalties and other information processing costs		17,890				20,908
Brokerage commissions		17,483				20,206
Compensation, benefits and other personnel		244,855				214,836
Stock-based compensation		11,777				10,966
Consulting, outsourcing and professional fees		80,598				85,579
Data processing and computer related		34,873				35,229
Facilities, supplies and other costs		44,909				42,474
Amortization		25,413				20,031
Depreciation		16,823				16,348
Total expenses		575,510				543,790
Income from operations		155,377				159,690
Net gain (loss) on investments		7,577				3,912
Interest and dividend income		4,417				4,380
Interest expense		(389		)		(485		)
Equity in earnings of unconsolidated affiliate		74,970				82,387
Net income before income taxes		241,952				249,884
Income taxes		90,892				88,087
Net income		151,060				161,797
Less: Net income attributable to the noncontrolling interest		(797		)		(1,234		)
Net income attributable to SEI			$150,263				$160,563
Diluted earnings per common share			$0.85				$0.86
Shares used to calculate diluted earnings per share		176,317				186,032
Basic earnings per common share			$0.86				$0.87
Shares used to calculate basic earnings per share		174,869				184,030

#PageNum#

---

SEI INVESTMENTS COMPANY

CONDENSED BALANCE SHEETS

(In thousands)

(Unaudited)

		September 30,				December 31,
		2012				2011
Assets
Cash and short-term investments			$397,677				$420,986
Restricted cash		6,000				6,000
Receivables, net		226,194				167,909
Securities owned		21,081				20,949
Other current assets		19,527				19,107
Total current assets		670,479				634,951
Property and equipment, net		131,889				129,548
Marketable securities		132,722				139,333
Capitalized software, net		310,168				309,133
Investment in unconsolidated affiliate		63,618				60,954
Other assets, net		23,528				20,640
Total assets			$1,332,404				$1,294,559
Liabilities
Current liabilities			$126,535				$151,073
Deferred income taxes		95,713				93,751
Other Long-term liabilities		11,079				8,276
Total SEI Investments Company shareholders’ equity		1,081,304				1,025,316
Noncontrolling interest		17,773				16,143
Total Equity		1,099,077				1,041,459
Total liabilities and equity			$1,332,404				$1,294,559

#PageNum#

---

SEI INVESTMENTS COMPANY

ENDING ASSET BALANCES

(In millions)

(Unaudited)

		Sept. 30,				Dec. 31,				Mar. 31,				Jun. 30,				Sept. 30,
		2011				2011				2012				2012				2012
Private Banks:
Equity/Fixed Income prgms.			$15,442				$16,435				$17,180				$16,848				$17,960
Collective Trust Fund prgms.		476				450				435				335				147
Liquidity funds		5,529				5,553				5,549				5,063				5,342
Total assets under mgmnt.			$21,447				$22,438				$23,164				$22,246				$23,449
Client assets under admin.		9,845				10,355				10,916				10,719				11,611
Total assets			$31,292				$32,793				$34,080				$32,965				$35,060
Investment Advisors:
Equity/Fixed Income prgms.			$24,757				$26,639				$29,722				$29,153				$30,864
Collective Trust Fund prgms.		1,392				1,298				1,199				705				370
Liquidity funds		2,653				2,505				1,643				1,880				1,868
Total assets under mgmnt.			$28,802				$30,442				$32,564				$31,738				$33,102
Institutional Investors:
Equity/Fixed Income prgms.			$46,259				$49,051				$54,537				$55,548				$59,852
Collective Trust Fund prgms.		510				492				424				415				153
Liquidity funds		3,356				3,888				3,725				2,958				3,272
Total assets under mgmnt.			$50,125				$53,431				$58,686				$58,921				$63,277
Investment Managers:
Equity/Fixed Income prgms.			$64				$57				$62				$61				$65
Collective Trust Fund prgms.		10,896				11,255				12,781				13,004				15,433
Liquidity funds		195				152				147				226				396
Total assets under mgmnt.			$11,155				$11,464				$12,990				$13,291				$15,894
Client assets under admin.		223,620				221,198				228,327				231,549				240,965
Total assets			$234,775				$232,662				$241,317				$244,840				$256,859
Investments in New Businesses:
Equity/Fixed Income prgms.			$490				$515				$568				$551				$534
Liquidity funds		41				37				34				30				29
Total assets under mgmnt.			$531				$552				$602				$581				$563
LSV:
Equity/Fixed Income prgms.			$49,444				$53,712				$60,607				$54,922				$58,886
Total:
Equity/Fixed Income prgms.			$136,456				$146,409				$162,676				$157,083				$168,161
Collective Trust Fund prgms.		13,274				13,495				14,839				14,459				16,103
Liquidity funds		11,774				12,135				11,098				10,157				10,907
Total assets under mgmnt.			$161,504				$172,039				$188,613				$181,699				$195,171
Client assets under admin.		233,465				231,553				239,243				242,268				252,576
Total assets			$394,969				$403,592				$427,856				$423,967				$447,747

(A)	Client assets under administration in the Investment Managers segment include $38.0 billion of assets balances that require limited services and therefore are at fee levels below our normal full service assets (as of September 30, 2012).

(B)	Equity/Fixed Income programs include $2.8 billion of assets invested in various asset allocation funds at

September 30, 2012.

(C)	In addition to the numbers presented, SEI also administers an additional $4.6 billion in Funds of Funds assets (as of

September 30, 2012) on which SEI does not earn an administration fee.

#PageNum#

---

SEI INVESTMENTS COMPANY

AVERAGE ASSET BALANCES

(In millions)

(Unaudited)

		3rd Qtr.				4th Qtr.				1st Qtr.				2nd Qtr.				3rd Qtr.
		2011				2011				2012				2012				2012
Private Banks:
Equity/Fixed Income prgms.			$16,592				$16,624				$17,116				$16,794				$17,527
Collective Trust Fund prgms.		505				464				436				396				230
Liquidity funds		5,210				5,401				5,581				5,115				5,401
Total assets under mgmnt.			$22,307				$22,489				$23,133				$22,305				$23,158
Client assets under admin.		10,364				10,290				10,211				10,631				10,867
Total assets			$32,671				$32,779				$33,344				$32,936				$34,025
Investment Advisors:
Equity/Fixed Income prgms.			$26,658				$26,094				$28,426				$29,103				$30,032
Collective Trust Fund prgms.		1,442				1,314				1,238				984				532
Liquidity funds		2,224				2,499				2,015				1,806				1,886
Total assets under mgmnt.			$30,324				$29,907				$31,679				$31,893				$32,450
Institutional Investors:
Equity/Fixed Income prgms.			$49,115				$48,504				$52,270				$54,998				$57,763
Collective Trust Fund prgms.		505				500				427				418				284
Liquidity funds		3,416				3,461				3,765				3,147				3,253
Total assets under mgmnt.			$53,036				$52,465				$56,462				$58,563				$61,300
Investment Managers:
Equity/Fixed Income prgms.			$52				$65				$58				$63				$62
Collective Trust Fund prgms.		11,292				10,773				11,983				12,991				14,797
Liquidity funds		200				219				190				235				287
Total assets under mgmnt.			$11,544				$11,057				$12,231				$13,289				$15,146
Client assets under admin.		236,953				224,633				224,547				229,873				237,155
Total assets			$248,497				$235,690				$236,778				$243,162				$252,301
Investments in New Businesses:
Equity/Fixed Income prgms.			$525				$515				$549				$550				$530
Liquidity funds		42				42				39				33				35
Total assets under mgmnt.			$567				$557				$588				$583				$565
LSV:
Equity/Fixed Income prgms.			$54,679				$54,021				$59,200				$55,994				$57,164
Total:
Equity/Fixed Income prgms.			$147,621				$145,823				$157,619				$157,502				$163,078
Collective Trust Fund prgms.		13,744				13,051				14,084				14,789				15,843
Liquidity funds		11,092				11,622				11,590				10,336				10,862
Total assets under mgmnt.			$172,457				$170,496				$183,293				$182,627				$189,783
Client assets under admin.		247,317				234,923				234,758				240,504				248,022
Total assets			$419,774				$405,419				$418,051				$423,131				$437,805

#PageNum#