Discover Financial Services (NYSE: DFS) reported its second quarter earnings recently and, once again, the results were a bit of a mixed bag. Bulls on the stock can point to the 9% year-over-year growth of revenue net of interest expense to $2.4 billion. Discover’s loan portfolio growth was also solid as total loans grew 8% to $78 billion and credit card loans, the company’s largest loan portfolio, increased 8% to $61.8 billion.