Three law firms­—Labaton Sucharow; Lieff Cabraser Heimann & Bernstein; and Thornton Law Firm—have admitted they double counted hours in a securities class action suit against State Street Bank that netted them $75 million, and have agreed to pay up to $2 million to cover the cost of an investigation into whether they overcharged for their work.

At a hearing in Boston federal court on Tuesday, U.S. District Judge Mark Wolf reportedly appointed Gerald Rosen, a recently retired federal judge, to conduct a probe of the plaintiffs firms’ fee request in connection with a $300 million settlement of securities claims against State Street.