U.S. electricity transmission company American Transmission Systems has proposed to issue $400 million of debt. We are assigning our 'BBB' rating to the proposed debt, plus we are assigning a 'BBB' corporate credit rating to the company. The stable outlook reflects that of parent, FirstEnergy Corp. On Dec. 10, 2009, Standard&Poor's Ratings Services assigned its 'BBB' corporate credit rating to Akron, Ohio-based electric transmission company American Transmission Systems Inc. (ATSI) and its 'BBB' rating to the company's proposed $400 million issuance of unsecured debt. The outlook is stable. ATSI is a wholly owned subsidiary of FirstEnergy Corp. (BBB/Stable/--), and we base ATSI's ratings on the consolidated credit profile of its parent. ATSI holds the electric transmission assets formerly