UNITED STATES

                       SECURITIES AND EXCHANGE COMMISSION

                             Washington, D.C. 20549

                                   FORM U-9C-3

                      QUARTERLY REPORT PURSUANT TO RULE 58

                      FOR THE QUARTER ENDED MARCH 31, 2005

                               EXELON CORPORATION

                            10 South Dearborn Street
                                   37th Floor
                     P.O. Box 805379 Chicago, IL 60680-5379














Inquiries concerning this Form U-9C-3
   should be directed to:                              Scott Peters
                                                       Exelon Corporation
                                                       10 South Dearborn Street
                                                       38th Floor
                                                       P.O. Box 805379
                                                       Chicago, IL 60680-5379




                                                                                         

TABLE OF CONTENTS

Item                                                                                         Page
Number                                                                                       Number

     1        Organization Chart                                                               3
     2        Issuances and Renewals of Securities and Capital Contributions
                  Part I - Issuances and Renewals of Securities                                5
                  Part II - Capital Contributions                                              5
     3        Associate Transactions
                  Part I - Transactions Performed by Reporting Companies on
                      Behalf of Associate Companies                                            6
                  Part II - Transactions Performed by Associate Companies
                      On Behalf of Reporting Companies                                         6
     4        Summary of Aggregate Investment                                                  7
     5        Other Investments                                                                8
     6        Financial Statements and Exhibits                                                9
              Signature                                                                       12







                                       2

ITEM 1. ORGANIZATION CHART - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Name of Reporting Company Energy or State of Date of % Voting Nature of Business Gas-Related Organization Organization Securities - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Exelon Corporation (a) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Exelon Energy Delivery Company, LLC (a) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Commonwealth Edison Company (a) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- PECO Energy Company (a) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- East Coast Natural Gas Cooperative, LLC Energy Delaware 03/15/1995 41.12% Energy-related (Category 9) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Horizon Energy Company * Energy Pennsylvania 02/06/1995 100% Energy-related (Category 5) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Exelon Ventures Company, LLC (a) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Exelon Synfuel I, LLC Energy Delaware 07/25/2003 100% Energy-related (Category 6) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- DTE Buckeye, LLC Energy Delaware 07/25/2003 -0-% Energy-related (Category 6) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Exelon Synfuel I1, LLC Energy Delaware 07/25/2003 100% Energy-related (Category 6) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- DTE Belews Creek, LLC Energy Delaware 07/25/2003 -0-% Energy-related (Category 6) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Exelon Synfuel III, LLC Energy Delaware 06/17/2004 100% Energy-related (Category 6) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- DTE Buckeye, Carbontronics Synfuels Energy Delaware 06/17/2004 -0-% Energy-related (Category Investors, L.P. 6) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Exelon Generation Company, LLC (a) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Penesco Company, LLC Energy Delaware 06/06/2001 100% Energy-related (Category 7,9) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Cenesco Company, LLC Energy Delaware 12/31/2001 100% Energy-related (Category 7) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- ExTex Retail Services Company, LLC Energy Delaware 05/12/2003 100% Energy-related (Category 5) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Exelon Allowance Management Company, LLC Energy Delaware 11/08/2001 100% Energy-related (Category 2) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Exelon Power Labs, LLC Energy Pennsylvania 11/08/2002 100% Energy-related (Category 7) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Exelon AOG Holding # 1, Inc. (a) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Exelon AOG Holding # 2, Inc. (a) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Exelon New England Power Marketing, LP Energy Delaware 03/24/1999 100% Energy-related (Category 5) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Exelon New England Holdings, LLC (a) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- ENEH Services, LLC (new) Energy Delaware 04/01/2004 100% Energy-related (Category 7) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Exelon Hamilton, LLC Energy Delaware 03/31/1999 100% Energy-related (Category 5) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Exelon SHC, Inc. (a) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Keystone Fuels, LLC Energy Delaware 10/17/2000 20.99% Energy-related (Category 9) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Conemaugh Fuels, LLC Energy Delaware 10/16/2002 20.72% Energy-related (Category 9) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- ExTex Marketing, LLC Energy Delaware 05/13/2002 100% Energy-related (Category 5) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- ExTex Power, LP Energy Delaware 05/13/2002 99% Energy-related (Category 5) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Exelon Energy Company Energy Delaware 01/04/1999 100% Energy-related (Category 5) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- AllEnergy Gas & Electric Marketing Company, Energy Delaware 09/12/2000 100% Energy-related (Category LLC 5) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Texas-Ohio Gas, Inc. Energy Texas 08/12/1987 100% Energy-related (Category 5) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- TEG Holdings, LLC (a) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Tamuin International, Inc. (a) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- North America Power Services, Inc. Energy Delaware 10/13/2004 100% Energy-related (Category 7) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Sithe Overseas Power Services, Ltd. Energy Virgin 10/13/2004 100% Energy-related (Category Islands 7) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Tamuin International Finance, LLC (a) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Tamuin International Finance II, LLC (a) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Tamuin Energy Management Services, Inc. Energy Delaware 10/13/2004 100% Energy-related (Category 7) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Tamuin Energy Management Services II, Energy Delaware 10/13/2004 100% Energy-related (Category Inc. 7) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Sithe Latin American Holdings, Ltd. (a) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Sithe PARDO Holdings, Ltd. (a) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Tamuin Holdings, LLC (a) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Sithe Tamuin Energy Services, S. de (a) R.L. de C.V. - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Tamuin Holdings II, LLC (a) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Sithe Tamuin Investments, S. de (a) R.L. de C.V. - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Tamuin Development Services, Energy Mexico 10/13/2004 50% Energy-related (Category S. de R.L. de C.V. 7) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Exelon Enterprises Company, LLC (a) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Exelon Services, Inc. Energy Delaware 07/13/1999 100% Energy-related (Category 1, 2,7) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Unicom Power Marketing Inc. Energy Delaware 07/28/1997 100% Energy-related (Category 5) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Exelon Enterprises Management, Inc. (a) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- ECPH, LLC (a) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Exelon Enterprises Investments, (a) Inc. - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- 3

- -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- ITEM 1. ORGANIZATION CHART (continued) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Name of Reporting Company Energy or State of Date of % Voting Nature of Business Gas-Related Organization Organization Securities - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- UTECH Climate Challenge Fund, Energy Delaware 06/30/1995 24.4% Energy-related (Category L.P. 2) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Adwin Equipment Company Energy Pennsylvania 08/05/1968 100% Energy-related (Category 6,7) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Exelon Thermal Holdings, Inc. Energy Delaware 08/05/1997 100% Energy-related (Category 6,7) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Exelon Thermal Development, Inc. Energy Delaware 02/05/1997 100% Energy-related (Category 6,7) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- ETT Boston Inc. Energy Delaware 12/22/1995 100% Energy-related (Category 6,7) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Northwind Boston LLC Energy Massachusetts 01/05/1996 25% Energy-related (Category 6,7) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- ETT North America Inc. Energy Delaware 07/18/1996 100% Energy-related (Category 6,7) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Northwind Thermal Technologies Energy Canada 08/01/1996 100% Energy-related (Category Canada Inc. 6,7) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- ETT Canada, Inc. Energy Canada 08/01/1996 100% Energy-related (Category 6,7) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Northwind Windsor Energy Canada 07/18/1996 50% Energy-related (Category 6,7) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- F&M Holdings Company, LLC Energy Delaware 09/18/2003 100% Energy-related (Category 1,4,7) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- II Services, Inc. Energy Delaware 05/28/1999 100% Energy-related (Category 1,2,7) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- EIS Engineering, Inc* Energy Delaware 12/11/2000 100% Energy-related (Category 7) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- InfraSource Field Services, Energy Oklahoma 11/23/1998 100% Energy-related (Category LLC* 7) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Fischbach and Moore Electric, Inc. Energy Delaware 08/12/1999 100% Energy-related (Category 1,2,7) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Rand-Bright Corporation* Energy Wisconsin 02/11/1985 100% Energy-related (Category 7) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- NEWCOSY, Inc Energy Delaware 08/12/1999 100% Energy-related (Category 1,2,7) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- NEWCOTRA, Inc. Energy Delaware 08/12/1999 100% Energy-related (Category 7) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Fishbach and Moore, Inc. Energy New York 04/01/1924 100% Energy-related (Category 7) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Fishbach and Moore Electrical Energy Delaware 07/22/1946 100% Energy-related (Category Contracting, Inc. 7) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- T.H. Green Electric Co., Inc. Energy New York 07/06/1926 100% Energy-related (Category 7) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- OSP Servicios S.A. de C.V. * Energy Mexico 09/30/1996 100% Energy-related (Category 7) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Universal Network Development Energy California 01/01/1901 49% Energy-related (Category Corp. 7) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- Oldco VSI Inc. Energy Delaware 04/20/2000 100% Energy-related (Category 1,2,7) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- EGW Meter Services, LLC Energy Delaware 12/01/2002 100% Energy-related (Category 1,2,7) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- EIS Investments, LLC * Energy Delaware 11/14/2000 100% Energy-related (Category 7) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- WCB Services, LLC* Energy Oklahoma 1/1/192001 49% Energy-related (Category 7) - -------------------------------------------------- --------- ------------- ------------- ---------- -------------------------- * Inactive (a) Directly and / or indirectly holds securities in energy-related companies. Name Changes - ------------- Sithe International, Inc. name changed to Tamuin International, Inc. January 26, 2005 Sithe Energy Management Services, Inc. name changed to Tamuin Energy Management Services, Inc. January 1, 2005 Sithe Energy Management Services II, Inc. name changed to Tamuin Energy Management Services II, Inc. January 1, 2005 Sithe Tamuin Holdings II, LLC name changed to Tamuin Holdings II, LLC January 26, 2005 Sithe Tamuin Development Services, S. de R.L. de C.V. name changed to 4

Tamuin Development Services, S. de R.L. de C.V. January 1, 2005 Sithe Tamuin Holdings, LLC name changed to Tamuin Holdings, LLC March 15, 2005 Sithe International Finance II, LLC name changed to Tamuin International Finance II, LLC March 29, 2005 Sithe International Finance, LLC name changed to Tamuin International Finance, LLC March 15, 2005 ITEM 2. ISSUANCES AND RENEWALS OF SECURITIES AND CAPITAL CONTRIBUTIONS Part I. ISSUANCES AND RENEWALS OF SECURITIES (in thousands) - --------------- --------------- ---------------- ------------- ------------------ --------------- ------------ -------------- Company Person to Issuing Type of Principal Whom Security Collateral Consideration Securities Security Amount of Issue or Was Issued Given With Received For (Borrower) Issued Security Renewal Cost of Capital (Lender) Security Each Security - --------------- --------------- ---------------- ------------- ------------------ --------------- ------------ -------------- II Services, Revolving $4 Issue LIBOR plus 50 F&M Holdings None $4 Inc. credit basis points Company, LLC - --------------- --------------- ---------------- ------------- ------------------ --------------- ------------ -------------- Exelon Revolving $1,256 Issue LIBOR plus 50 Exelon None $1,256 Services, Inc credit basis points Enterprises Company, LLC - --------------- --------------- ---------------- ------------- ------------------ --------------- ------------ -------------- Fischbach & Revolving $12,146 Issue LIBOR plus 50 F&M Holdings None $12,146 Moore credit basis points Company, LLC Electric, Inc. - --------------- --------------- ---------------- ------------- ------------------ --------------- ------------ -------------- F&M Holdings Revolving $8,690 Issue LIBOR plus 50 Exelon None $8,690 Company, LLC credit basis points Enterprises Company, LLC - --------------- --------------- ---------------- ------------- ------------------ --------------- ------------ -------------- Part II. CAPITAL CONTRIBUTIONS (in thousands) - ------------------------------------------- ---------------------------------------- ---------------------------------------- Company Contributing Capital Company Receiving Capital Amount of Capital Contribution - ------------------------------------------- ---------------------------------------- ---------------------------------------- Exelon Generation Company, LLC Exelon Power Labs, LLC $4,548 - ------------------------------------------- ---------------------------------------- ---------------------------------------- Exelon Generation Company, LLC Exelon Energy Company $3,903 - ------------------------------------------- ---------------------------------------- ---------------------------------------- Exelon AOG Holding #1, Inc. Exelon New England Power Marketing, LP $969 - ------------------------------------------- ---------------------------------------- ---------------------------------------- Exelon AOG Holding #2, Inc. Exelon New England Power Marketing, LP $95,929 - ------------------------------------------- ---------------------------------------- ---------------------------------------- 5

ITEM 3. ASSOCIATE TRANSACTIONS Part I. Transactions Performed by Reporting Companies on Behalf of Associate Companies (in thousands) - ------------------------------------------------------------------------------------------------------------------------- Direct Reporting Company Associate Company Types of Costs Indirect Costs Cost of Total Amount Rendering Services Receiving Services Services Rendered Charged Charged Capital Billed - ------------------------------------------------------------------------------------------------------------------------- Exelon Power Labs, LLC Exelon Business Measuring & test $409 $409 Services Company equipment, technical services - PECO - ------------------------------------------------------------------------------------------------------------------------- Exelon Power Labs, LLC Exelon Business Measuring & test $68 $68 Services Company equipment, technical services - ComEd - ------------------------------------------------------------------------------------------------------------------------- Exelon Power Labs, LLC Exelon Generation Measuring & test $1,957 $1,957 Company, LLC equipment, technical services - ------------------------------------------------------------------------------------------------------------------------- Exelon Power Labs, LLC AmerGen Measuring & test $271 $271 equipment, technical services - ------------------------------------------------------------------------------------------------------------------------- Exelon Power Labs, LLC ExTex LaPorte Measuring & test $2 $2 Limited equipment, Partnership technical services - ------------------------------------------------------------------------------------------------------------------------- Exelon Energy Company Exelon Lease costs $112 $112 Enterprises Company, LLC - ------------------------------------------------------------------------------------------------------------------------- Exelon Energy Company Exelon Services, Lease costs $56 $56 Inc. - ------------------------------------------------------------------------------------------------------------------------- North America Power Sithe Tamuin HR services $75 $75 Services, Inc. Energy Services, S. de R.L. de C.V. - ------------------------------------------------------------------------------------------------------------------------- ENEH Services, LLC Exelon New Operations and $3 $3 Boston, LLC maintenance - ------------------------------------------------------------------------------------------------------------------------- Part II. Transactions Performed by Associate Companies on Behalf of Reporting Companies (in thousands) - ------------------------------------------------------------------------------------------------------------------------- Direct Reporting Company Associate Company Types of Costs Indirect Costs Cost of Total Amount Rendering Services Receiving Services Services Rendered Charged Charged Capital Billed - ------------------------------------------------------------------------------------------------------------------------- Exelon Business F&M Holdings Legal $278 $278 Services Company Company, LLC - ------------------------------------------------------------------------------------------------------------------------- Exelon Business Exelon Services, Legal, IT and $40 $40 Services Company Inc. accounting - ------------------------------------------------------------------------------------------------------------------------- Exelon Business Exelon Thermal Legal $5 $5 Services Company Holdings, Inc. - ------------------------------------------------------------------------------------------------------------------------- Exelon Business Exelon Power HR, IT and $47 $47 Services Company Labs, LLC accounting - ------------------------------------------------------------------------------------------------------------------------- Exelon Generation Exelon Power Management services $53 $53 Company, LLC Labs, LLC - ------------------------------------------------------------------------------------------------------------------------- Exelon Business Exelon Energy HR, legal, IT and $50 $50 Services Company Company accounting - ------------------------------------------------------------------------------------------------------------------------- 6

ITEM 4. SUMMARY OF AGGREGATE INVESTMENT March 31, 2005 (in thousands) Investments in energy-related companies: Total consolidated capitalization of Exelon Corporation as of March 31, 2005 $24,135,000 Line 1 Total capitalization multiplied by 15% (line 1 multiplied by 0.15) 3,620,250 Line 2 Greater of $50 million or line 2 3,620,250 Line 3 Total current aggregate investment subsequent to October 20, 2000 (categorized by major line of energy-related business): Energy-related business category 2 $342,644 Energy-related business category 5 172,192 Energy-related business category 7 261,524 Energy-related business category 9 12,374 Energy-related business category 10 23,217 Total current aggregate investment 811,951 Line 4 ---------- Difference between the greater of $50 million or 15% of capitalization and the total aggregate investment of the registered holding company system (line 3 less line 4) $2,808,299 Line 5 ========== Investments in gas-related companies: NONE 7

ITEM 5. OTHER INVESTMENTS Filed under confidential treatment pursuant to Rule 104(b). 8

ITEM 6 - FINANCIAL STATEMENTS AND EXHIBITS A. Financial Statements - ----------------------- (1) Exhibit A-1 Statement of Income of Exelon Services, Inc. for the three months ended March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). (2) Exhibit A-2 Balance Sheet of Exelon Services, Inc. at March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). (3) Exhibit A-3 Statement of Income of Exelon Thermal Holdings, Inc. for the three months ended March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). (4) Exhibit A-4 Balance Sheet of Exelon Thermal Holdings, Inc. at March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). (5) Exhibit A-5 Statement of Income of Unicom Power Marketing, Inc. for the three months ended March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). (6) Exhibit A-6 Balance Sheet of Unicom Power Marketing, Inc. at March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). (7) Exhibit A-7 Statement of Income of Adwin Equipment Company for the three months ended March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). (8) Exhibit A-8 Balance Sheet of Adwin Equipment Company at March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). (9) Exhibit A-9 Statement of Income of F&M Holdings Company, LLC for the three months ended March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). (10) Exhibit A-10 Balance Sheet of F&M Holdings Company, LLC at March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). (11) Exhibit B-1 Statement of Income of Penesco Company, LLC for the three months ended March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). (12) Exhibit B-2 Balance Sheet of Penesco Company, LLC at March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). (13) Exhibit B-3 Statement of Income of Cenesco Company, LLC for the three months ended March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). (14) Exhibit B-4 Balance Sheet of Cenesco Company, LLC at March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). (15) Exhibit B-5 Statement of Income of Exelon Allowance Management Company, LLC for the three months ended March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). (16) Exhibit B-6 Balance Sheet of Exelon Allowance Management Company, LLC at March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). (17) Exhibit B-7 Statement of Income of ExTex Marketing, LLC for the three months ended March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). 9

(18) Exhibit B-8 Balance Sheet of ExTex Marketing, LLC at March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). (19) Exhibit B-9 Statement of Income of Exelon New England Power Marketing LP for the three months ended March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). (20) Exhibit B-10 Balance Sheet of Exelon New England Power Marketing LP at March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). (21) Exhibit B-11 Statement of Income of Exelon Hamilton, LLC for the three months ended March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). (22) Exhibit B-12 Balance Sheet of Exelon Hamilton, LLC at March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). (23) Exhibit B-13 Statement of Income of Exelon Energy Company for the three months ended March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). (24) Exhibit B-14 Balance Sheet of Exelon Energy Company at March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). (25) Exhibit B-15 Statement of Income of Exelon PowerLabs, LLC for the three months ended March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). (26) Exhibit B-16 Balance Sheet of Exelon PowerLabs, LLC at March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). (27) Exhibit B-17 Statement of Income of ENEH Services, LLC for the three months ended March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). (28) Exhibit B-18 Balance Sheet of ENEH Services, LLC at March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). (29) Exhibit B-19 Statement of Income of ExTex Retail Services Company, LLC for the three months ended March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). (30) Exhibit B-20 Balance Sheet of ExTex Retail Services Company, LLC at March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). (31) Exhibit B-21 Statement of Income of North America Power Services, Inc. for the three months ended March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). (32) Exhibit B-22 Balance Sheet of North America Power Services, Inc. at March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). (33) Exhibit B-23 Statement of Income of Sithe Overseas Power Services, Ltd. for the three months ended March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). (34) Exhibit B-24 Balance Sheet of Sithe Overseas Power Services, Ltd. at March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). (35) Exhibit B-25 Statement of Income of Tamuin Energy Management Services, Inc. for the three months ended March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). 10

(36) Exhibit B-26 Balance Sheet of Tamuin Energy Management Services, Inc. at March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). (37) Exhibit B-27 Statement of Income of Tamuin Energy Management Services II, Inc. for the three months ended March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). (38) Exhibit B-28 Balance Sheet of Tamuin Energy Management Services II, Inc. at March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). (39) Exhibit B-29 Statement of Income of Sithe Tamuin Energy Services, S. de R.L. de C.V. for the three months ended March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). (40) Exhibit B-30 Balance Sheet of Sithe Tamuin Energy Services, S. de R.L. de C.V. at March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). (41) Exhibit B-31 Statement of Income of Sithe Tamuin Energy Services II, S. de R.L. de C.V. for the three months ended March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). (42) Exhibit B-32 Balance Sheet of Sithe Tamuin Energy Services II, S. de R.L. de C.V. at March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). (43) Exhibit C-1 Statement of Income of Exelon Synfuel I, LLC for the three months ended March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). (44) Exhibit C-2 Balance Sheet of Exelon Synfuel I, LLC at March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). (45) Exhibit C-3 Statement of Income of Exelon Synfuel II, LLC for the three months ended March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). (46) Exhibit C-4 Balance Sheet of Exelon Synfuel II, LLC at March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). (47) Exhibit C-5 Statement of Income of Exelon Synfuel III, LLC for the three months ended March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). (48) Exhibit C-6 Balance Sheet of Exelon Synfuel III, LLC at March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). (49) Exhibit C-7 Statement of Income of Horizon Energy Company for the three months ended March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). (50) Exhibit C-8 Balance Sheet of Horizon Energy Company at March 31, 2005 - filed under confidential treatment pursuant to Rule 104(b). B. Exhibits - ----------- None. 11

SIGNATURE Pursuant to the requirements of the Public Utility Holding Company Act of 1935, Exelon Corporation has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized. Date: May 31, 2005 Exelon Corporation Registrant By:/s/ Matthew F. Hilzinger ------------------------ Vice President and Corporate Controller With the above signature, I also hereby certify that the corresponding report on Form U-9C-3 for the three months ended March 31, 2005 has been filed with Exelon Corporation's interested state commissions whose names and addresses are listed below. Ms. Elizabeth M. Rolando, Chief Clerk Illinois Commerce Commission 527 East Capitol Avenue Springfield, Illinois 62706 James J. McNulty, Secretary Pennsylvania Public Utility Commission P.O. Box 3265 Harrisburg, Pennsylvania 17105-3265 12