Exhibit 99.1
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Joint Filing Agreement
The undersigned hereby agree that the statement on Schedule 13D with
respect to the Common Stock of Constellation Energy Group, Inc., is, and any
amendment thereto signed by each of the undersigned shall be, filed on behalf of
each undersigned pursuant to and in accordance with the provisions of 13d-1(k)
under the Securities Exchange Act of 1934, as amended.
Dated: December 29, 2008 MidAmerican Energy Holdings Company
By: /s/ Xxxxxxx X. Xxxxxxxx
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Name: Xxxxxxx X. Xxxxxxxx
Title: Senior Vice President, General Counsel
and Corporate Secretary
Dated: December 29, 2008 MEHC Investment, Inc.
By: /s/ Xxxxxxx X. Xxxxxxxx
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Name: Xxxxxxx X. Xxxxxxxx
Title: Vice President and Secretary
