The prospect of a further increase in record U.S. crude stockpiles that have undercut OPEC’s output curbs kept oil investors anxious, with prices stuck near $48 a barrel. Futures in New York rose 0.4 percent after they slipped 0.5 percent on Monday. They alternated between gains and losses through four sessions last week, but the gyrations were limited to within $2 a barrel. U.S. stockpiles are forecast to have gained 1.37 million barrels last week. While the Organization of Petroleum Exporting Countries and other nations are cutting output, concern is growing they need more time to trim global inventories. If industry data due Tuesday and government data on Wednesday show U.S. stockpiles are continuing to rise, it would be further evidence that the effect of output curbs by other producers is being blunted by rising American supply and drilling activity. Five OPEC countries joined with non-member Oman to voice […]