Standard&Poor's Ratings Services assigned its 'AAA' program rating and 'A+' underlying rating for credit program to East Central Independent School District (ISD), Texas' series 2015 unlimited-tax refunding bonds. At the same time, Standard&Poor's affirmed its 'A+' underlying rating on the district's existing general obligation (GO) debt. Standard&Poor's also affirmed its 'A+' underlying rating (SPUR) on the district's GO debt not issued under the Texas Permanent School Fund bond guarantee program. The outlook on all the ratings is stable. The program rating reflects our assessment of the district's eligibility for, and participation in, the Texas Permanent School Fund, which provides the security of a permanent fund of assets that could be used to meet debt