OLDWICK, N.J.--(BUSINESS WIRE)-- A.M. Best Co. has affirmed the financial strength rating of A- (Excellent) and issuer credit rating of “a-” of National Guaranty Insurance Company of Vermont (NGIC) (Burlington, VT). The outlook for both ratings is stable.

The ratings of NGIC reflect its excellent risk-adjusted capitalization, operating performance and liquidity position, as well as its sophisticated risk management strategy and practices, conservative investment strategy, its management team’s extended experience in the industry and its parent, Waste Management, Inc.’s (WM) operational controls.