U.S. bank stocks fell in premarket trading, with Goldman Sachs (GS.N) down 2.1%, Bank of America (BAC.N) and Citigroup (C.N) down 1.7%, Morgan Stanley (MS.N) down 1.6%, JPMorgan Chase (JPM.N) down 1.3% and Wells Fargo (WFC.N) down 1.4% after Moody's downgraded the U.S. rating.