Moody's Investors Service downgraded Onondaga County, N.Y. to Aa2 from Aa1.
The downgrade, announced March 11, affects $333 million in outstanding debt.
The action concluded a review for possible downgrade that Moody's had initiated in January in conjunction with a new local government general obligation methodology
The county was among 256 localities placed on review for downgrade or upgrade after Moody's adopted the new methodology Jan. 15.
The new methodology reduced the importance of economic factors to 30% from 40% in determining its ratings and increased the importance of debt and unfunded pensions to 20% from 10% of its ratings.
The downgrade "reflects the county's well-managed financial operations with satisfactory reserve levels that are expected to remain stable in the near term, sizable and diverse economic base, and an above average but manageable debt position," Moody's analyst Valentina Gomez and vice president Malcolm Thompson wrote.
As strengths, Onondaga County has a large stable tax base with institutional presence and adequate reserve levels, the analysts said. For challenges, analysts note the county's significant debt including for remediation of Onondaga Lake.
Onondaga County had 467,000 people as of 2010. Its seat is Syracuse.
Moody's has a stable outlook on the rating.
