Moody's Investors Service affirmed the "A3" rating on Prince Frederick, Md.-based Calvert Health System, affecting $31 million in outstanding revenue bonds.
The affirmation results from a number of factors, including Calvert's strong market position, favorable leverage ratios and maintenance of revenue.
The outlook was revised to negative from stable, reflecting Moody's expectation that the system will continue to struggle with operating performance in fiscal years 2017 and 2018.