The Securities and Exchange Commission has not necessarily reviewed the information in this filing and has not determined if it is accurate and complete.
The reader should not assume that the information is accurate and complete.

  UNITED STATES SECURITIES AND EXCHANGE COMMISSION OMB APPROVAL
 Washington, D.C. 20549
FORM 13F
OMB Number:   3235-0006
Expires:          July 31, 2015
Estimated average burden
hours per response:       23.8


FORM 13F COVER PAGE


Report for the Calendar Year or Quarter Ended:
12-31-2019
 
Check here if Amendment:      Amendment Number:
 
This Amendment (Check only one.):    is a restatement.
     adds new holdings entries.

Institutional Investment Manager Filing this Report:

Name:SEI INVESTMENTS CO 
Address:1 FREEDOM VALLEY DRIVE 
 OAKS PA 19456-1100 

Form 13F File Number:  028-16454 


The institutional investment manager filing this report and the person by whom it is signed hereby represent that the person signing the report is authorized to submit it, that all information contained herein is true, correct and complete, and that it is understood that all required items, statements, schedules, lists, and tables, are considered integral parts of this form.

Person Signing this Report on Behalf of Reporting Manager:

Name:Michael N. Peterson 
Title:Executive Vice President 
Phone: 610-676-1000 

Signature, Place, and Date of Signing:

Michael N. Peterson Oaks,  PENNSYLVANIA 02-06-2020 
[Signature][City, State][Date]

Do you wish to provide information pursuant to Special Instruction 5?    X  Yes          No

Additional Information

SEI Investments Company (SEI) is the parent holding company of certain institutional investment managers, as defined by Section 13(f) of the Securities Exchange Act of 1934, as amended (the "Act"). For purposes of the reporting requirements under Section 13(f) of the Act, and the rules promulgated thereunder, SEI does not exercise, and therefore disclaims, investment discretion with respect to any Section 13(f) securities positions over which its investment operating subsidiaries exercise such discretion. To the extent, however, that SEI's ownership interest in such subsidiaries may nevertheless give rise to a Form 13F obligation for SEI, the information required by Form 13F is reported herein on behalf of the following subsidiaries: SEI Investments Management Corporation ("SIMC"), SEI Trust Company and SEI Investments Canada Company (SEI Canada). Voting authority with respect to the Section 13(f) securities reported herein resides with and is exercised by SEI's operating subsidiaries, unless otherwise indicated. Although SEI has not been delegated voting authority over such Section 13(f) securities, and disclaims such voting authority, pursuant to instruction 12b.viii of Form 13F, and for that purpose only, such Section 13(f) securities are reported as "Sole Voting Authority." SIMC and SEI Canada each serve as an investment adviser to a number of pooled investment vehicles, which may include mutual funds, hedge funds, private equity funds, collective investment trusts and offshore investment funds (together, the "Pooled Investment Vehicles"). In addition, SIMC sponsor and may serve as adviser to, separately managed account programs (SMA Programs) . SIMC and SEI Canada may act as a "manager of managers" whereby each retain, subject to SIMC's and SEI Canada's oversight, respectively, sub-advisers to buy and sell securities on behalf of such Pooled Investment Vehicles and SMA Programs. To the extent that SIMC's and SEI Canada's role as a manager of managers could give rise to a Form 13F obligation, SIMC or SEI Canada has instructed its sub-advisers to file a Form 13F with respect to such securities and has included such sub-advisers in the "list of other managers reporting for this manager" below.

Report Type (Check only one.):

     13F HOLDINGS REPORT. (Check here if all holdings of this reporting manager are reported in this report.)

     13F NOTICE. (Check here if no holdings reported are in this report, and all holdings are reported by other reporting manager(s).)

X  13F COMBINATION REPORT. (Check here if a portion of the holdings for this reporting manager are reported in this report and a portion are reported by other reporting manager(s).)


List of Other Managers Reporting for this Manager
[If there are no entries in this list, omit this section.]

Form 13F File NumberName
028-17130 361 Capital, LLC 
028-05990 Acadian Asset Management LLC 
028-05508 AJO, LP 
028-10562 AllianceBernstein L.P. 
028-04895 Analytic Investors, LLC 
028-10120 AQR Capital Management LLC 
028-17137 Arcus 
028-13791 ArrowMark Partners 
028-05615 Axiom International Investors 
028-18146 Benefit Street Partners 
028-02951 Beutel Goodman Capital Management 
028-18913 Blackcrane Capital, LLC 
028-12820 Brigade Capital Management, LP 
028-11728 Causeway 
028-11563 Coho Partners 
028-14668 Copeland Capital Management, LLC 
028-10492 Falcon Point Capital 
028-14036 Fiera Capital Corp. 
028-18845 Fondsmaeglerselskabet Maj Invest A/S 
028-12836 Guggenheim Capital Llc 
028-11957 Hillsdale Investment Management Inc. 
028-04211 Intech Investment Management LLC 
028-12634 Investec Asset Management Ltd. 
028-14777 J O HAMBRO CAPITAL MANAGEMENT LTD 
028-11937 JP Morgan Investment Management 
028-17689 Kettle Hill Capital Management, LLC 
028-13608 LMCG Investments, LLC 
028-06580 LSV Asset Management 
028-13124 Macquarie Investment Management 
028-03673 ManuLife Asset Management LLC 
028-17488 Maple-Brown Abbott 
028-13243 Mar Vista Investment Partners, LLC 
028-03743 Marathon Asset Management, LP 
028-04632 Martingale Asset Management L P 
028-13573 Neuberger Berman Group LLC 
028-17435 NN Investment Partners Holdings N.V. 
028-01474 NWQ Investment Management Company, LLC 
028-03042 PanAgora Asset Management Inc. 
028-04558 Parametric Portfolio Associates LLC 
028-12690 PCJ Investment Counsel Ltd 
028-13350 Poplar Forest Capital LLC 
028-01549 PRINCIPAL GLOBAL INVESTORS 
028-14009 QS Investors LLC 
028-19339 Qtron Investments LLC 
028-11173 Quantiative Management Associates 
028-10674 Ramius Advisors LLC 
028-14481 RWC Asset Management LLP 
028-04691 Schafer Cullen Capital Management Inc. 
028-10613 Snow Capital Management LP 
028-11300 Spectrum Asset Management, Inc. 
028-00733 State Street Bank & Trust 
028-10640 Towle & Co 
028-07104 WCM Investment Management/CA 
028-17022 William Blair & Co