The West Family Foundation Paoli, PA 19301 Dear Mr. West:

Exhibit 99.6

July 31, 2003

The West Family Foundation

00 Xxxxxxxxxx Xxxx

Xxxxx, XX  00000

Dear Xx. Xxxx:

Reference is made to the Collateral Agreement, dated as of September 16, 2002 and subsequently amended on November 25, 2002, by and among JPMorgan Chase Bank and The West Family Foundation (the “Collateral Agreement”) and the other Collateral Agreements identified on Annex A hereto (collectively, the “Collateral Agreements”).  Capitalized terms used but not defined herein shall have the meanings given to such terms in the Collateral Agreement.

The parties hereto acknowledge their mutual intention that the arrangements contemplated by the Collateral Agreements not result in the Bank falling within the definition of an “Acquiring Person” for purposes of that certain Rights Agreement, dated as of December 10, 1998, between SEI Investments Company and American Stock Transfer & Trust Company.  Accordingly, as a matter of clarification, each of the parties hereto agree that the Collateral Agreement is hereby amended by inserting a new Section 13(g) into the Collateral Agreement:

(g)           Notwithstanding the foregoing or anything else to the contrary in this Agreement, at any time so long as that certain Rights Agreement, dated as of December 10, 1998, between SEI Investments Company and American Stock Transfer & Trust Company (including, without limitation, any extension thereof or any succeeding comparable rights agreement or plan) remains in effect, upon a Default, the Bank shall not be entitled to exercise any rights or remedies otherwise contemplated by this Agreement or by the other Collateral Agreements in respect of shares of SEI Investments Company that constitute “Collateral” under this Agreement or under the other Collateral Agreements to the extent that such exercise would result in the Bank acquiring or having the right to acquire, vote or dispose of shares of SEI Investment Company that constitute more than 19.9% of the shares then outstanding.

This amendment to the Collateral Agreement shall be deemed effective as of September 16, 2002.  Please confirm your agreement to the foregoing by signing the enclosed copy of this letter in the space provided below and returning it to me.

			Very truly yours,
			JPMorgan Chase Bank
			By:	/s/ Xxxxxx X. Xxxxxxx
				Name:
				Title:
Acknowledged and agreed to:
The West Family Foundation
By:	/s/ Xxxxxx X. Xxxx, Xx.
	Name: Xxxxxx X. Xxxx, Xx.
	Title: President

Annex A

1.		Collateral Agreement, dated as of September 16, 2002 and subsequently amended on November 25, 2002, by and among JPMorgan Chase Bank, Xxxxxx X. Xxxx, Xx. and Xxxxxxx X. Xxxx
2.		Collateral Agreement, dated as of September 16, 2002 and subsequently amended on November 25, 2002, by and among JPMorgan Chase Bank and the West Family Foundation
3.		Collateral Agreement, dated as of September 16, 2002 and subsequently amended on November 25, 2002, by and among JPMorgan Chase Bank, Xxxxxxx X. Xxxx, Xxxxxxx X. Xxxxx and Xxxxxx Xxxxx Xxxx, as Trustees under the Agreement of Trust dated December 22, 1980, established by Xxxxxx X. Xxxx, Xx., for the benefit of Xxxxxx Xxxxx Xxxx
4.		Collateral Agreement, dated as of September 16, 2002 and subsequently amended on November 25, 2002, by and among JPMorgan Chase Bank, Xxxxxxx X. Xxxx, Xxxxxxx X. Xxxxx and Xxxxxx Xxxxx Xxxx, as Trustees under the Agreement of Trust dated December 22, 1980, established by Xxxxxx X. Xxxx, Xx., for the benefit of Xxxxxx Xxxxxx West
5.		Collateral Agreement, dated as of September 16, 2002 and subsequently amended on November 25, 2002, by and among JPMorgan Chase Bank and Xxxxxx Xxxxx Xxxx as Trustee under the Trust Agreement dated September 1, 1998 (GRAT II) for the benefit of Xxxxxx Xxxxx Xxxx
6.		Collateral Agreement, dated as of September 16, 2002 and subsequently amended on November 25, 2002, by and among JPMorgan Chase Bank and Xxxxxx Xxxxxx West as Trustee under the Trust Agreement dated September 1, 1998 (GRAT II) for the benefit of Xxxxxx Xxxxxx West