Calpine has announced an agreement to purchase 4,490 megawatts of gas-fired generating capacity of Connectiv Energy from Pepco Holdings Inc. for $1.65 billion. We are affirming the 'B' corporate credit rating and all debt ratings on Calpine Corp. While we consider the acquisition a credit positive, it is uncertain whether Connectiv is large enough to improve the Calpine' ratings, especially given the ongoing merchant downturn. SAN FRANCISCO (Standard&Poor's) April 26, 2010--Standard&Poor's Ratings Services affirmed its 'B' corporate credit rating and all debt ratings on Calpine Corp. The outlook is stable. Calpine Corp.'s purchase of 4,490 megawatts (MW) of gas-fired generating capacity of Connectiv Energy from Pepco Holdings Inc. for $1.65 billion is a positive for credit