NEW YORK (Standard&Poor's) June 9, 2015--Standard&Poor's Ratings Services assigned its 'A-' long-term rating to Missouri Southern State University's (MSSU) series 2015 auxiliary enterprise system refunding revenue bonds. In addition, Standard&Poor's affirmed its 'A-' rating on MSSU's series 2014A, 2014B, and 2008 auxiliary enterprise system revenue bonds. The outlook for all ratings is stable. "The rating reflects stabilized enrollment in fall 2014 and 2013 following a devastating tornado in Joplin that caused a decrease in headcount for fall 2011 and 2012," said Standard&Poor's credit analyst Charlene Butterfield. "Moreover, the rating reflects improved retention rates for fall 2014 and 2013." The university recorded full accrual deficits in fiscal years 2014 and 2013, the result