Filed by EXELON CORPORATION
                              Pursuant to Rule 425
                              Under the Securities Act of 1933
                              Subject Company: EXELON CORPORATION
                              Commission File No.: 333-37082


          Set forth below is the text of a letter sent to certain
shareholders of Unicom who have not yet voted.

          The following communications contain certain
"forward-looking statements" within the meaning of the Private
Securities Litigation Reform Act of 1995.  These statements are
based on management's current expectations and are naturally
subject to uncertainty and changes in circumstances.  Actual
results may vary materially from the expectations contained
herein.  The forward-looking statements herein include statements
about future financial and operating results and the proposed
merger involving PECO Energy Company and Unicom Corporation.  The
following factors, among others, could cause actual results to
differ materially from those described herein:  inability to
obtain, or meet conditions imposed for, governmental approvals
for the merger; failure of the PECO Energy Company or Unicom
Corporation stockholders to approve the merger; the risk that the
PECO Energy Company and Unicom Corporation businesses will not be
integrated successfully; and other economic, business,
competitive and/or regulatory factors affecting PECO Energy
Company's and Unicom's businesses generally.  More detailed
information about those factors is set forth in the joint proxy
statement/prospectus regarding the proposed merger.  Neither PECO
Energy Company nor Unicom Corporation is under any obligation to
(and expressly disclaims any such obligation to) update or alter
its forward-looking statements whether as a result of new
information, future events or otherwise.


                   * * * * * * * * * * * * * *

          Investors and security holders are urged to read the
joint proxy statement/prospectus regarding the business
combination transaction referenced in the foregoing information
because it contains important information.  The joint proxy
statement/prospectus has been filed with the Securities and
Exchange Commission by Exelon Corporation.  The joint proxy
statement/prospectus was declared effective by the Commission on
May 15, 2000.  Investors and security holders may obtain a free
copy of the joint proxy statement/prospectus and other documents
filed by PECO Energy Company and Unicom Corporation with the
Commission at the Commission's web site at www.sec.gov.  The
joint proxy statement/prospectus and these other documents may
also be obtained for free from PECO Energy Company or from Unicom
Corporation.


  June 9, 2000



  Dear Unicom Shareholder:

  By now, you should have received your proxy
  statement/prospectus and proxy card for the annual meeting, as
  well as a brochure further discussing the merger of Unicom
  Corporation with PECO Energy Company to form Exelon
  Corporation, which will be voted on at the annual meeting. We
  have not yet received your vote. Your immediate attention to
  this proposal is very important and I urge you to take
  advantage of your right to vote. YOUR FAILURE TO VOTE WILL
  COUNT AS A VOTE AGAINST THE MERGER.  BECAUSE WE NEED APPROVAL
  BY TWO-THIRDS OF ALL OUTSTANDING UNICOM COMMON SHARES TO
  APPROVE THE MERGER, IT IS ESSENTIAL THAT ALL UNICOM
  SHAREHOLDERS VOTE RIGHT AWAY.

  Your Board of Directors has carefully reviewed the merger and
  recommends that you vote "FOR" the approval of the merger
  agreement and "FOR" all the other items on the agenda.


  If you have already voted, you do not need to do so again.
  However, if you have not yet voted, you may use the enclosed
  proxy card to vote, or you may vote by telephone or Internet
  as explained on the enclosed proxy card.  Your Unicom shares
  will not be voted unless you either sign and return your proxy
  card or vote by telephone or Internet.

  I urge you to read the proxy statement/prospectus because it
  contains important information regarding the merger proposal.
  The proxy statement/prospectus is available for free at the
  Securities and Exchange Commission's web site at www.sec.gov
  or at Unicom's web site at www.ucm.com. If you have any
  questions about the merger or the other items to be voted on
  at the annual meeting, please call Morrow & Co., Inc., our
  proxy solicitor, at 1-800-566-9061.

  Sincerely,


  /s/ John P. McGarrity
  ------------------------
      John P. McGarrity
      Secretary