Oil prices held firm above $51 a barrel on Thursday after surging on news of a drop in U.S. crude stocks and on expectations of strong gasoline demand as the U.S. summer driving season gets under way. U.S. light sweet crude for July delivery was up 20 cents at $51.18 a barrel after a jump of 2.6 percent on Wednesday. Brent crude rose nine cents to $50.16 a barrel, adding to gains of more than a dollar on Wednesday. "The latest data may finally be signaling an end to the substantial builds... in the U.S. crude stocks," Martin King, energy analyst for FirstEnergy Capital Corp., said in a report. Fund managers said the two-week dip below $50 that ended on Wednesday had lured more buyers in. "I think when it was sub-$50, people saw that as an opportunity to get involved in the market," said Mark Keenan of MPC Commodity Fund. He predicted long-term price strength, though the coming days could see choppy trading as key technical levels are tested and the market closes early on Friday ahead of the U.S. Memorial Day weekend that launches the U.S. driving season.