U.S. bank earnings rose 7% in the second quarter over last year, although other measures of bank profitability remained depressed. The 6,348 U.S. banks earned $43 billion in the second quarter, a 7.3% increase from the same period a year ago. Banks boosted their loan balances by $185 billion, or 2.2%, compared with the first quarter of this year, the highest quarterly increase since 2010. They showed 2.8% growth in commercial and industrial loans compared with the previous quarter, a 3.1% increase in credit card balances and 1.3% growth in residential mortgage loans. Net interest margin, a measure of what banks earn on loans, remained depressed as the Federal Reserve maintains rock-bottom rates. Banks’ net interest margin was 3.06% in the second quarter, below the prior-year rate of 3.15%.