Fitch Ratings on April 28 upgraded 's long-termissuer default rating to BBB+ from BBB as a reflection of the company's soundcredit profile and regulatory predictability in Illinois.

Fitch also revised its ratings outlook on the subsidiary tostable from positive.

Illinois in October 2011 implemented the formula rate plan,which provides for annual rate adjustments and mitigates the impact of a risingCapEx program. "Fitch expects the annual FRP rate adjustments to allowComEd to sustain and moderately improve its currently sound financial positionover the next few years," the rating agency said.

Aside from ComEd, Fitch affirmed issuer default ratings ofPECO Energy Co. andBaltimore Gas and Electric Co.at BBB+ and Exelon Generation Co.LLC at BBB. The rating outlook is stable for the three Exelonsubsidiaries.