Commonwealth Edison Company Exhibit (10)-27 One First National Plaza Commonwealth Edison Company P.O. Box 767 Form 10-K File No. 1-1839 Chicago, IL 60690-0767 May 31, 1995 [ComEd logo] Mr. Samuel K. Skinner President Commonwealth Edison Company P. O. Box 767 Chicago, Illinois 60690-0767 Dear Sam: The purpose of this letter is to confirm our agreement with respect to your employment as President of Commonwealth Edison Company and Unicom Corporation. We have agreed that the calculation of the "SERP benefit" as set forth in paragraph number one of the letter agreement between Commonwealth Edison and you dated December 16, 1992, will be modified to refer to the "highest annual earnings" instead of "highest annual base pay." For this purpose, "highest annual earnings" means the highest base pay rate and any incentive pay that would be taken into account under the Commonwealth Edison Company Service Annuity System for the applicable period. All other terms of the December 16, 1992 letter agreement remain unaffected by this change. If the above is consistent with the agreements reached in our discussion, please countersign in the space provided below. Sincerely, James J. O'Connor James J. O'Connor Chairman and Chief Executive Office Samuel K. Skinner Samuel K. Skinner President