Ownership Submission
FORM 4
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940
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(Print or Type Responses)
1. Name and Address of Reporting Person *
WEST ALFRED P JR
   2. Issuer Name and Ticker or Trading Symbol
SEI INVESTMENTS CO [SEIC] 		5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
__X__ Director __X__ 10% Owner
_____ Officer (give title below) _____ Other (specify below)
(Last)
(First)
(Middle)
ONE FREEDOM VALLEY DRIVE		 3. Date of Earliest Transaction (Month/Day/Year)
12/23/2009
(Street)

OAKS, PA 19456		 4. If Amendment, Date Original Filed(Month/Day/Year)
 6. Individual or Joint/Group Filing(Check Applicable Line)
_X_ Form filed by One Reporting Person
___ Form filed by More than One Reporting Person
(City)
(State)
(Zip)
Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1.Title of Security
(Instr. 3)		 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code
(Instr. 8)		 4. Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4 and 5)		 5. Amount of Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 3 and 4)		 6. Ownership Form: Direct (D) or Indirect (I)
(Instr. 4)		 7. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V Amount (A) or (D) Price
Common Stock 12/23/2009   J(1)   6,750,888 A $ 0 16,760,896 (2) D  
Common Stock 12/23/2009   J(1)   80,495 A $ 0 128,495 (3) I Held by Wife
Common Stock 12/23/2009   J(1)   9,075,000 D $ 0 0 I Held by AP West Associates (4)
Common Stock               471,416 I Held by the 1980 Minority Trust - Alfred P. West III (5)
Common Stock               2,796,000 I Held by Life Trust - Alfred P. West III (5)
Common Stock               2,810,590 I Held by the 1980 Life Trust - Andrew Palmer West (5)
Common Stock               2,801,470 I Held by the 1980 Life Trust - Angela Paige West
Common Stock               64,400 I Held by the West Senior Securities Fund, L.P. (6)
Common Stock               4,376 I Held by the Residuary Trust (7)
Common Stock               64,394 I Held by the Marital Trust (GST Exempt) (8)
Common Stock               64,754 I Held by the Trust (Non-GST Exempt) (8)

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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 3)		 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year) 3A. Deemed Execution Date, if any (Month/Day/Year) 4. Transaction Code
(Instr. 8)		 5. Number of Derivative Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4, and 5)		 6. Date Exercisable and Expiration Date
(Month/Day/Year)		 7. Title and Amount of Underlying Securities
(Instr. 3 and 4)		 8. Price of Derivative Security
(Instr. 5)		 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 4)		 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 4)		 11. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
WEST ALFRED P JR
ONE FREEDOM VALLEY DRIVE
OAKS, PA 19456		   X   X    

Signatures

 Ruth Montgomery (Attorney in Fact)   12/28/2009
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1) Pro rata liquidating distribution from AP West Associates, L.P. ("West L.P."), of which the reporting person was both general partner and a limited partner and of which the reproting person's wife was a limited partner.
(2) Includes 675,088 shares received as a pro rata liquidating distribution from West L.P., 160,990 of which are attributable to the reporting person's general partnership and 514,098 of which are attributable to the reporting person's limited partnership interest in West L.P. In prior reports, the reporting person reported beneficial ownershhip of 9,075,000 shares held by West L.P., which represented 100% of the shares held by West L.P.
(3) Includes 80,495 shares received as a liquidating distribution from West L.P.
(4) West L.P. was liquidated on December 23, 2009 and the shares held by the West L.P. were distributed pro rata to its general partner and limited partners. Mr. West disclaimed and continues to disclaim, beneficial ownership of the shares held by West L.P., except to the extent of his pecuniary interest therein.
(5) These shares are held in trusts for the benefit of Mr. West's children. Mr. West's wife is the trustee or a co-trustee of these trust. Mr. West disclaims beneficial ownership of the shares held in these trusts.
(6) West Senior Securities Fund, L.P. is a limited partnership in which the Residuary Trust, of which Mr. West is trustee, holds a 1% general partnership interest and a 9.5% limited partnership interest. Mr. West disclaims beneficial owernship of the shares held by West Senior Securities Fund, L.P., except to the extent of his pecuniary interest therein.
(7) The trust that holds these shares (the "Residuary Trust") is for the benefit of Mr. West's mother and certain descendants of Mr. West's father. The Residuary Trust was created upon the death of Mr. West's father under the terms of an existing trust that Mr. West's father had established prior to his death. In connection with the establishment of the Residuary Trust, Mr. West became the trustee of the Residuary Trust in September 2002. Mr. West disclaims beneficial ownership of the shares held by the Residuary Trust, except to the extent of his pecuniary interest therein.
(8) Mr. West is the trustee of the Marital Trusts (GST and non-GSTexempt), which holds shares for the benefit of Mr. West's mother.

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