By Nate Raymond
(Reuters) - A U.S. judge set a May 2015 trial date on Friday for BP Plc to face claims in a lawsuit accusing the company of misleading investors about the severity of the 2010 Gulf of Mexico oil spill.
U.S. District Judge Keith Ellison in Houston set the May 18, 2015 date nearly a month after granting class certification to the shareholders in the lawsuit.
The judge at the time said investors who bought BP's American depository shares between April 26 and May 28, 2010 could pursue claims BP "low-balled" the oil flow rate, and that the share price "did not reflect the magnitude of the disaster."
He also declined to certify a separate investor group that claimed BP overstated its ability to manage safety issues before the explosion, saying damages would be too difficult to calculate.
Investors can often recover more money at lower cost by suing as a group. BP's ADS price fell 37 percent from the start of the class period to the first trading day after it ended.
BP has said it would appeal the decision to certify the class.
The lead plaintiffs are New York State Comptroller Thomas DiNapoli, who oversees that state's Common Retirement Fund, and the Ohio Public Employees' Retirement System.
Representatives for BP and the plaintiffs did not immediately respond to requests for comment.
The case is In re: BP Plc Securities Litigation, U.S. District Court, Southern District of Texas, No. 10-md-02185.
(Reporting by Nate Raymond in New York; Editing by Noeleen Walder and Dan Grebler)