Among the day's gainers, Amazon.com AMZN.O was up 0.7% with its "Prime Day" 48-hour shopping event going on this week. By Caroline Valetkevitch NEW YORK, July 11 (Reuters) - U.S. stocks were higher on Tuesday afternoon, helped by gains in financial shares, while investors awaited key inflation reports and the start of second-quarter earnings in the coming days. JPMorgan Chase & Co JPM.N shares gained 1.5% after Jefferies upgraded the stock to a "buy" ahead of the bank's quarterly results due on Friday.