Oil Prices Plunge 4% After US, Iran Reach Preliminary Nuclear Deal

Oil prices plunged more than 4 percent Thursday after the U.S. and other world powers announced a preliminary agreement to ensure that Iran's nuclear program remains peaceful. The proposal sets a final deadline of June 30 for the talks. The deal, which would remove Western sanctions against Tehran, ignited fear that new Iranian oil exports would add to a global market already facing oversupply.