Global oil-processing margins shrank 42% last quarter: BP data Oil majors enjoyed one of the best years for refining in 2015 The world’s biggest oil companies, supported during crude’s collapse by a buoyant refining business, have lost that buffer as brimming fuel stockpiles swamp demand. Profits from turning oil into gasoline and diesel contracted 42 percent last quarter from a year earlier to an average $11.60 a barrel, the weakest for the time of year since 2010, industry data from BP Plc show. The impact of that will be apparent as earnings for the period roll in over the coming weeks. Refineries benefited from oil’s two-year slide that began in mid-2014 because the cost of feedstock fell while fuel demand rose. That led to over-production and huge stockpiles that now can’t be absorbed. For oil majors including Exxon Mobil Corp. and BP, that erodes a valuable source of income […]