Morgan Stanley&Co. Inc. Trust floater certificates series 2006-1539, relating to Arizona Transportation Board highway revenue bonds series 2006, are rated 'AAA/A-1'. The long-term component of the rating is based on the underlying bond. The short-term component of the rating is based on a guarantee provided by Morgan Stanley and a liquidity facility provided by Morgan Stanley Municipal Funding Inc. until Nov. 29, 2007. Morgan Stanley&Co. Inc. Trust residual certificates series 2006-1539, relating to Arizona Transportation Board highway revenue bonds series 2006, are rated 'AAA'. The rating is based on the underlying bond.