S&P Global Ratings raised the rating to "A+" from "A" on Saginaw, Mich.-based Covenant HealthCare System's series 2010H bonds.
"The rating action reflects our view of Covenant's sustained financial improvement coupled with stable balance sheet measures," said S&P analyst Brian Williamson.
The outlook is stable, reflecting S&P's view of Covenant's strong balance sheet, dominant market share and solid operating results.