CNBC | Oil prices tumble 3% after OPEC data adds to glut worries CNBC Oil prices tumbled as much as 3 percent on Friday after OPEC said October output reached another record, casting doubt on whether its plan to limit production is achievable or enough to ease persisting oversupply in the market. The Organization of the ... Oil price falls again as IEA report adds to pressure on Opec OPEC's Oil Production Cut in Doubt as Output Flows OPEC points to even bigger 2017 oil surplus as its output jumps |