...NEW YORK (S&P Global Ratings) Nov. 15, 2017-- S&P Global Ratings revised its outlook to positive from stable and affirmed its 'A+' rating on Michigan Finance Authority's revenue debt, issued for MidMichigan Health. "The positive outlook reflects our view of MidMichigan's steady operational performance in recent years, with good maximum annual debt service coverage and a solid balance sheet, particularly with respect to system medians for the rating level," said S&P Global Ratings credit analyst Avani Parikh. The positive outlook reflects our expectation that over the two-year outlook period MidMichigan will continue to sustain at least stable, if not improved, operating margins supporting good MADS coverage for the rating, despite the potential for some dilution associated with the West Branch affiliation. We could raise the rating within the two-year outlook period if MidMichigan sustains a trend of at least 2% operating margins, thereby supporting steady MADS coverage in excess of 4x...