Oil prices, stocks hammered after OPEC decision A day after OPEC voted not to cut oil production in response to a weakening global market, prices plummeted to their lowest level since 2010. The vote by the Organization of the Petroleum Exporting Countries in Vienna Thursday to maintain production levels of 30 million barrels a day — about four times that of the United States — was not a surprise. Thursday’s events have pressed speculation that OPEC is abandoning its traditional role as swing producer, in which it could cause oil prices to rise and fall by adjusting its production a percentage point or two. In the 1980s, OPEC crashed the global oil market by increasing supply at a time the markets were already weak, putting many U.S.