CNBC | Harold Hamm warns oil prices below $40 will idle US drilling, cautions producers to be 'prudent' CNBC U.S. shale oil pioneer Harold Hamm on Wednesday warned that sub-$40 crude would cause many U.S. producers to stop drilling and warned fellow CEOs to exercise discipline. U.S. crude prices have plunged nearly 18 percent this year, giving up the gains ... Continental Resources CEO Hamm warns sub-$50 oil "not sustainable" |