The cut came a year after OPEC had raised its production quota to 31.5 mbpd on December 4, 2015. OPEC was struggling to maintain market share. Its share fell from 44.5 percent in 2012 to 41.8 percent in 2014. Its share fell because of a 16 percent increase in U.S. shale oil production. As the oil supply rose, prices fell from $108.54 in April 2012 to $34.72 in December 2015. That was one of the biggest drops in oil price history.
OPEC waited to cut oil production because it didn't want to see its market share drop further. It produces oil more cheaply than its U.S. competition. The cartel toughed it out until many of the shale companies went bankrupt. That created a boom and bust in shale oil.
