Shares of Amazon.com Inc. AMZN, +11.15% shot up 11.8% in morning trading Friday, in the wake of second-quarter results, to put them on for the best one-month gain in more than 15 years. The stock has run up 28.8% in July, to snap a three-month losing streak in which it tumbled 34.8%, amid growing concerns over the effect historically high inflation and a slowing economy would have on the ecommerce giant's customers.