ComEd 2006 Annual Report Download - page 159

Report of Independent Registered Public Accounting Firm
To the Shareholders and Board of Directors of PECO Energy Company:
In our opinion, the consolidated financial statements listed in the index appearing under Item 15(a)(4)(i)
present fairly, in all material respects, the financial position of PECO Energy Company and its
subsidiaries (PECO) at December 31, 2006 and 2005, and the results of their operations and their
cash flows for each of the three years in the period ended December 31, 2006 in conformity with
accounting principles generally accepted in the United States of America. In addition, in our opinion,
the financial statement schedule listed in the index appearing under Item 15(a)(4)(ii) presents fairly, in
all material respects, the information set forth therein when read in conjunction with the related
consolidated financial statements. These financial statements and the financial statement schedule are
the responsibility of PECO's management. Our responsibility is to express an opinion on these financial
statements and the financial statement schedule based on our audits. We conducted our audits of
these statements in accordance with the standards of the Public Company Accounting Oversight Board
(United States). Those standards require that we plan and perform the audit to obtain reasonable
assurance about whether the financial statements are free of material misstatement. An audit includes
examining, on a test basis, evidence supporting the amounts and disclosures in the financial
statements, assessing the accounting principles used and significant estimates made by management,
and evaluating the overall financial statement presentation. We believe that our audits provide a
reasonable basis for our opinion.
As discussed in Note 1 to the consolidated financial statements, PECO changed its method of
accounting for conditional asset retirement obligations as of December 31, 2005, and its method of
accounting for stock-based compensation as of January 1, 2006.
PricewaterhouseCoopers LLP
Chicago, Illinois
February 13, 2007
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