The heart of the Q2 earnings season is upon us with several big banks set to report their quarterly results on Friday, July 12.Wall Street will be closely monitoring JPMorgan’s (JPM)  results as the largest bank in the United States but also paying close attention to Citigroup (C)  which is the third largest domestic bank. To that point, Citigroup recently announced a significant restructuring plan to streamline its operations in a bid to enhance efficiency.That said, let’s see if now is a good time to buy ...