While the S&P 500 surged 5.3% in May, US bank stocks experienced a mixed market performance. The market-cap-weighted S&P US BMI Banks index was down 3.0% last month on a total return basis. All 13 of the largest US banks by market cap as of May 29 declined. JPMorgan Chase & Co., Bank of America Corp. and Wells Fargo & Co. dragged down the index, with returns of negative 4.4%, negative 3.5% and negative 5.1%, respectively.