U.S. stocks opened lower after data showed producer prices rose slightly more than expected in November amid a jump in the cost of services, but the trend is moderating, with annual inflation at the factory gate posting its smallest increase in 1-1/2 years. O/R Netflix Inc NFLX.O gained 5.9% after Wells Fargo upgraded the streaming giant's stock to "overweight" from "equal weight". Boeing Co BA.N gained 1.4% on a report of plans to announce a deal with United Airlines UAL.O for orders of 787 Dreamliner next week.