NEW YORK, March 4 (Reuters) - Moody's Investors Service on Wednesday said it may cut its ratings on Wells Fargo & Co (WFC.N: Quote, Profile, Research) and Bank of America (BAC.N: Quote, Profile, Research), and changed its outlook on JPMorgan Chase & Co (JPM.N: Quote, Profile, Research) to negative, from stable, indicating it is more likely to be cut in the next two years.

Moody's currently rates both Wells Fargo and JPMorgan "Aa3," its fourth highest investment grade. Bank of America is rated "A1," the fifth highest investment grade.

The review on Wells Fargo and Bank of America was prompted by concerns that their capital ratios could deteriorate in 2009 from current levels because of the potential need to take high loan loss provisions in 2009, Moody's said in a statement.

Wells Fargo's low capital ratios "result from the fact that the equity Wells Fargo raised for its purchase of Wachovia was, in Moody's view, modest in comparison to the amount and quality of the acquired Wachovia assets," Moody's said.

Capital generation at the bank may be constrained as Wells Fargo will need to record provisions and merger-related expenses in 2009 and 2010 against assets at Wachovia that were not marked down on Dec. 31, 2008, Moody's said.

Bank of America's Tier 1 capital is strong, but it is heavily dependent on preferred stock and hybrid securities, Moody's added.

The reviews for possible downgrade are expected to be completed by the end of March.

JPMorgan's outlook was revised to negative, meanwhile, on concerns the bank's results will be "saddled by sustained high provisions and credit costs for the coming four to six quarters, due to increasing financial strains for U.S. consumers and the global recession," Moody's said.

"As a result, JPMorgan's capital generation could be modest at best," the credit ratings agency said.