Frank M. Clark became Chairman and Chief Executive Officer of Commonwealth Edison Company ("ComEd") (an electric energy distribution subsidiary of Exelon Corporation) in November 2005, having served as President of ComEd since October 2001. Mr. Clark also served as Executive Vice President and Chief of Staff to the Exelon Corporation Chairman from 2004 to 2005. Since joining ComEd in 1966, Mr. Clark rose steadily through the ranks, holding key leadership positions in operational and policy-related responsibilities including regulatory and governmental affairs, customer service operations, marketing and sales, information technology, human resources and labor relations, and distribution support services. Mr. Clark is a director of Harris Financial Corp. (financial services) and Waste Management, Inc. (waste disposal services). Mr. Clark also serves as a trustee of the University of Chicago Hospitals and Health System and DePaul University.