OPEC is resisting pressure to cut oil production while demand slumps as it tests how low prices must go to make U.S. shale oil unprofitable. As producers become more efficient, that floor is sinking. The Organization of Petroleum Exporting Countries boosted output by the most in 13 months in September, even as crude plunged into a bear market and demand growth weakens to a five-year low, according to the International Energy Agency . Saudi Arabia and Kuwait , the largest and third-largest members of OPEC, indicated the price slump doesn’t warrant immediate production cuts, the IEA said. While OPEC acted as a “swing producer” over the past decade, responding to surpluses by cutting output, it’s now letting oil slide to see if North American production can withstand lower prices, said Antoine Halff , head of the IEA’s oil industry and markets division. So far drillers are showing no signs […]