Plaintiffs lawyers at Cohen Milstein Sellers & Toll moved a step forward this week in a securities class action alleging that Credit Suisse duped investors into buying mortgage-backed securities (MBS) backed by shoddy home loans.

In a 21-page ruling that may hold promise for other MBS investors, U.S. District Judge Paul Crotty in Manhattan agreed to expand the certified class in the Credit Suisse case to include holders of $825 million in securities that weren’t purchased by any named plaintiff. Citing an influential 2012 decision by the U.S. Court of Appeals for the Second Circuit in NECA-IBEW Health & Welfare Fund v. Goldman Sachs, Crotty ruled that the class could encompass a 2007 MBS offering that involved the same mortgage originator and similar alleged conduct as those already in the case.