With mortgage putback exposure "mostly ring fenced," Harralson said that "investors should now look to the efficiency ratio and profitability statistics as the next large earnings lever. Management has been consistent in saying it can get to a 60% or below efficiency. If STI could show expense progress in this difficult quarter, investors could be heartened that a 60% efficiency ratio is possible." A bank's efficiency ratio is, essentially, the number of pennies of overhear expenses it incurs, for each dollar of revenue. STI data by YCharts Interested in more on SunTrust? See TheStreet Ratings' report card for this stock.