Chicago Tribune reported that though the new rating is still investment grade, it has put the city on a lower tier and could increase the cost of the city government to borrow money.

　　The rating "reflects the city's massive and growing unfunded pension liabilities," the new rating report said.

　　Moody's concluded Chicago has the highest level of unfunded pension debt "of any rated U.S. local government." "As such, the city's financial operations will remain structurally imbalanced," the report stated.

　　Moody's downgrade of credit worthiness of Chicago came one week after Standard & Poor's Ratings Services issued a report saying financially strapped Chicago had far more wherewithal to restore its financial health than bankrupt Detroit.

　　Earlier, two other major agencies maintained their existing debt ratings for upcoming city bond issue by Chicago.