Standard&Poor's Ratings Services lowered its rating on Advanced Technology Academy (ATA), Mich.'s series 2008 revenue bonds to 'BB+' from 'BBB-'. The outlook is stable. The rating action reflects our opinion of ATA's consistently weak liquidity and reliance on the short-term borrowing of state aid anticipation notes; flat enrollment despite expectations of enrollment growth in fall 2015, leading to a decline in per pupil funding; and limited demand flexibility. The rating further reflects our opinion of: The academy's consistently weak liquidity with 20 days' and 19 days' cash on hand (DCOH) as of fiscal years 2015 and 2014, respectively, half of which includes state aid anticipation notes used to offset state funding delays; A heavy and continued reliance of