Key TakeawaysUber shares jumped Tuesday after the company's second-quarter earnings came in well above analysts' expectations.Gross bookings rose 19% year-over-year, while profits more than doubled to $1.02 billion.JPMorgan analysts said Uber's stock buyback plan that started during Q2 should "ramp" over the next several quarters. Uber (UBER) stock jumped Tuesday as the ridesharing giant's second-quarter earnings beat analysts' estimates as gross bookings grew 19% year-over-year. The company reported a 16% ...