The international price of oil is denominated by the U. S. dollar. "When the dollar is strong, when it increases in value, oil becomes cheaper. World oil players are producing more oil than consumers are using, supply is up due to the U.S. shale oil boom and the halting return of Libya's production." The value of the U.S. dollar bottomed in May 2014. The Federal Reserve ended a six year program to stimulate the economy by purchasing $15 billion in bonds at the end of Oct 2014. As the dollar began to strengthen, the price of oil dropped dramatically.