(As filed December 14, 2001)

                                                                File No. 70-9645

                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                     POS-AMC
                        (Post-Effective Amendment No. 3)

                                       to

                                    FORM U-1
                             APPLICATION/DECLARATION
                                      UNDER
                 THE PUBLIC UTILITY HOLDING COMPANY ACT OF 1935

                               EXELON CORPORATION
             (AND SUBSIDIARIES IDENTIFIED ON SIGNATURE PAGE HERETO)
                            10 South Dearborn Street
                                   37th Floor
                             Chicago, Illinois 60603

                      EXELON INFRASTRUCTURE SERVICES, INC.
                                 200 Yale Avenue
                           Morton, Pennsylvania 19070

                              EXELON SERVICES INC.
                              2315 Enterprise Drive
                           Westchester, Illinois 60154

                  (Names of companies filing this statement and
                    addresses of principal executive offices)

            --------------------------------------------------------

                               EXELON CORPORATION

          (Name of top registered holding company parent of applicants)

             -------------------------------------------------------

         John W. Rowe                                Corbin A. McNeill, Jr.
  Co-Chief Executive Officer                       Co-Chief Executive Officer
      Exelon Corporation                               Exelon Corporation
   10 South Dearborn Street                            2301 Market Street
          37th Floor                                      P.O. Box 8699
    Chicago, Illinois 60603                     Philadelphia, Pennsylvania 19101

                   (Names and addresses of agents for service)

             ------------------------------------------------------





      The Commission is requested to send copies of all notices, orders and
       communications in connection with this Application/Declaration to:

                                Harvey B. Dikter,
                    Senior Vice President and General Counsel
                      Exelon Infrastructure Services, Inc.
                                 200 Yale Avenue
                           Morton, Pennsylvania 19070

                           William T. Baker, Jr. Esq.
                            Thelen Reid & Priest LLP
                               40 West 57th Street
                            New York, New York 10019





     Post-Effective Amendment No. 1, filed in this proceeding on April 4, 2001,
is hereby amended as follows:(1)

     1.  By adding the following paragraph at the end of Item 1.3:

     "As indicated, under the Merger Order, the Commission granted an interim
exemption under Section 13(b) of the Act from the at-cost standards of Rule 90
and 91 with respect to certain types of services rendered to and by the Utility
Subsidiaries, including the infrastructure services provided by EIS and
mechanical contracting services provided by EES, as described above. The Merger
Order specifies that, as of January 1, 2002, all these transactions will be
performed at cost in accordance with Rules 90 and 91. It is now requested that,
pending a decision in this proceeding, the Commission issue a supplemental order
extending the interim exemption granted under the Merger Order from December 31,
2001 until June 30, 2002. The six-month extension will afford the Commission the
additional time needed for it to fully consider the policy implications raised
by applicants and, if determined to be appropriate, formulate new policies in
ruling in exemption requests under Section 13(b), without disrupting existing
contractual relationships among the Utility Subsidiaries and their affiliates,
all of which are currently in compliance with applicable affiliate transaction
rules adopted by Pennsylvania and Illinois Commissions. It is requested that the
Commission issue a supplemental order extending the interim exemption as soon as
practical and in any event not later than December 31, 2001, so that the status
of any existing affiliate agreements is not called into question."

     2.  By amending and restating Item 2 to read as follows:

     "The incremental fees, commissions and expenses incurred or to be incurred
(1) in connection with Post-Effective Amendment No. 1 are estimated at not more
than $10,000 and (2) in connection with Post-Effective Amendment No. 2 are
estimated at not more than $5,000."

     3.  By amending and restating Item 3.3 to read as follows:

     "Rule 54. The proposed transaction is also subject to the requirements of
      -------
Rule 54. Rule 54 provides that in determining whether to approve the issue or
sale of a security by a registered holding company for purposes other than the
acquisition of an "exempt wholesale generator" ("EWG") or a "foreign utility
company" ("FUCO"), or other transactions by such registered holding company or
its subsidiaries other than with respect to EWGs or FUCOs, the Commission shall
not consider the effect of the capitalization or earnings of any subsidiary
which is an EWG or a FUCO upon the registered holding company if paragraphs (a),
(b) and (c) of Rule 53 are satisfied.

     Exelon currently does not meet all of the conditions of Rule 53(a). As of
September 30, 2001, Exelon's "aggregate investment," as defined in
Rule 53(a)(1), in EWGs and FUCOs was approximately $744 million which is in
excess of the 50% of Exelon's average consolidated retained earnings of $1,022
million at September 30, 2001 which is the "safe


-------------------

1    Post-Effective Amendment No. 2, which was filed on October 1, 2001, relates
     to matters that are not the subject of Post-Effective Amendment No. 1.





harbor" limitation contained in Rule 53(a). However, by orders dated November 2,
2000 and December 8, 2000 (HCAR Nos. 27266 and 27296, together the "Financing
Orders"), the Commission has authorized Exelon to increase its "aggregate
investment" in EWGs and FUCOs to an amount of up to $4 billion. Therefore,
although Exelon's "aggregate investment" in EWGs and FUCOs currently exceeds the
50% "safe harbor" limitation, this investment level is permitted under the
Financing Orders.

     In any event, even taking into account the capitalization of and earnings
from EWGs and FUCOs in which Exelon has an interest, there would be no basis for
withholding approval of the proposed transaction. With regard to capitalization,
since the issuance of the Financing Orders, there has been no material adverse
impact on Exelon's consolidated capitalization resulting from Exelon's
investments in EWGs and FUCOs. At September 30, 2001, Exelon's consolidated
capitalization consists of 33 % equity, 3% preferred securities, 62 % long-term
debt (including current maturities of long-term debt), and 2 % short-term debt.
These ratios are within acceptable industry ranges. The proposed transaction
will not have any material impact on capitalization. Further, since the date of
the Financing Orders, there has been no material change in Exelon's level of
earnings from EWGs and FUCOs.

     Exelon satisfies all of the other conditions of paragraphs (a) and (b) of
Rule 53. With reference to Rule 53(a)(2), Exelon maintains books and records in
conformity with, and otherwise adheres to, the requirements thereof. With
reference to Rule 53(a)(3), no more than 2% of the employees of Exelon's
domestic public utility companies render services, at any one time, directly or
indirectly, to EWGs or FUCOs in which Exelon directly or indirectly holds an
interest. With reference to Rule 53(a)(4), Exelon will continue to provide a
copy of each application and certificate relating to EWGs and FUCOs and relevant
portions of its Form U5S to each regulator referred to therein, and will
otherwise comply with the requirements thereof concerning the furnishing of
information. With reference to Rule 53(b), none of the circumstances enumerated
in subparagraphs (1), (2) and (3) thereunder have occurred. Finally, Rule 53(c)
by its terms is inapplicable since the proposed transaction does not involve the
issue or sale of a security to finance the acquisition of an EWG or FUCO."


                                       2



                                   SIGNATURES

     Pursuant to the requirements of the Public Utility Holding Company Act of
1935, the undersigned companies have duly caused this statement to be signed on
their behalves by the undersigned thereunto duly authorized.

                                         EXELON CORPORATION

                                         By: /s/ Randall Mehrberg
                                                 ------------------------------
                                         Name:   Randall Mehrberg
                                         Title:  Senior Vice President and
                                                 General Counsel

                                         EXELON INFRASTRUCTURE SERVICES, INC.

                                         By: /s/ Harvey B. Dikter
                                                 ------------------------------
                                         Name:   Harvey B. Dikter
                                         Title:  Senior Vice President and
                                                 General Counsel

                                         EXELON SERVICES INC.

                                         By: /s/ Kenneth H. Beard
                                                 ------------------------------
                                         Name:   Kenneth H. Beard
                                         Title:  President

                                         COMMONWEALTH EDISON COMPANY
                                         PECO ENERGY COMPANY
                                         EXELON ENERGY GENERATION COMPANY,LLC
                                         BY EXELON CORPORATION

                                         By: /s/ Randall Mehrberg
                                                 ------------------------------
                                         Name:   Randall Mehrberg
                                         Title:  Senior Vice President and
                                                 General Counsel

Date: December 14, 2001


                                       3