U.S. oil markets have been transformed over the last decade by the emergence of oil trading and storage as a major business in its own right, separate from production and refinery operations. At the end of 2014, there were more than 390 million barrels of crude stored at refineries and tank farms as well as in transit in pipelines and barges and in storage tanks at oilfields. Commercial crude stockpiles had climbed by more than 100 million barrels since the end of 2004, almost 38 percent, according to annual data published by the U.S. Energy Information Administration (EIA). By the end of April 2015, commercial stocks had climbed by another 105 million barrels to a record 491 million as the oversupply in the global oil market ended up […]