Discover Financial Services (NYSE:DFS) reported better-than-expected second-quarter earnings results, after the closing bell on Wednesday. Discover reported GAAP earnings of $6.06 per share, beating the estimate of $3.07 per share, and quarterly Net Interest Income (NII) of $3.524 billion, according to data from Benzinga Pro. Net interest income for the quarter increased by $347 million, or 11% year-over-year, driven by higher average receivables and net interest margin expansion. Net interest margin was 11.17%, up 11 basis points versus the prior year. "Discover's fundamental operating performance remains very good, as shown by our loan growth, margin expansion ...