Standard&Poor's Ratings Services raised its ratings on four Bank of America N.A. letter of credit-backed municipal issues to 'AA+' from 'AA' and removed the ratings from CreditWatch with positive implications where they were placed on Nov. 1, 2006. This action follows Standard&Poor's upgrade of Bank of America N.A. to 'AA+/A-1+' from 'AA/A-1+' and its subsequent removal from CreditWatch with positive implications.