SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): September 22, 1999 Commission Registrant; State of Incorporation; IRS Employer File Number Address; and Telephone Number Identification No. - ----------- ---------------------------------- ------------------ 1-11375 UNICOM CORPORATION 36-3961038 (an Illinois corporation) 37th Floor, 10 South Dearborn Street Post Office Box A-3005 Chicago, Illinois 60690-3005 312/394-7399 1-1839 COMMONWEALTH EDISON COMPANY 36-0938600 (an Illinois corporation) 37th Floor, 10 South Dearborn Street Post Office Box 767 Chicago, Illinois 60690-0767 312/394-4321 Item 5. Other Events On September 23, 1999, Unicom Corporation ("Unicom") and PECO Energy Company, a Pennsylvania Corporation ("PECO"), issued a joint press release announcing that they, along with a wholly- owned subsidiary of PECO, had entered into an Agreement and Plan of Exchange and Merger, dated as of September 22, 1999 (the "Merger Agreement"). In connection with approving the Merger Agreement and the transactions contemplated thereby, the Unicom Board of Directors approved an amendment to Unicom's Rights Agreement, to render it inapplicable to the transactions contemplated by the Merger Agreement. In addition, the Rights Agreement will now expire on the earlier of (i) February 2, 2008, (ii) the time at which the Rights are redeemed pursuant to the Rights Agreement, (iii) the time at which the Rights are exchanged pursuant to the Rights Agreement or (iv) the time that is immediately prior to the effective time of the merger contemplated by the Merger Agreement. The Merger Agreement and the Amendment to the Rights Agreement will be filed by Unicom with the SEC within the next few days. A press release announcing the transaction is filed herewith as Exhibit 99 and is incorporated herein by reference. The description of the Merger Agreement and the Amendment to Rights Agreement set forth above and in the press release does not purport to be complete and is qualified in its entirety by reference to the provisions of such agreements. SIGNATURES Pursuant to the requirements of the Securities Exchange Act of 1934, the registrants have duly caused this report to be signed on their behalf by the undersigned thereunto duly authorized. UNICOM CORPORATION (Registrant) Date: September 23, 1999 By: John C. Bukovski ------------------------ John C. Bukovski Senior Vice President COMMONWEALTH EDISON COMPANY (Registrant) Date: September 23, 1999 By: John C. Bukovski ------------------------- John C. Bukovski Senior Vice President Exhibit Index Exhibit Number Description of Exhibit 1. None 2. None 4. None 16. None 17. None 20. None 23. None 24. None 27. None 99. Press release dated September 23, 1999