Key TakeawaysCiti, Wells Fargo and JPMorgan Chase will report earnings on Friday, with Bank of America to follow on Tuesday.Investors will be watching banks' levels and forecasts for net interest income, a key measure of lending profitability.Analysts expect some banks to slow plans for stock buybacks. Big bank earnings kick off Friday with Citi (C), Wells Fargo (WFC) and JPMorgan Chase (JPM) reporting their second-quarter results. Bank of America (BAC) is set to follow on Tuesday. Analysts expect few surp ...