As the government fights big banks over the financial crisis, plaintiffs lawyers at Quinn Emanuel Urquhart & Sullivan are waging a separate battle — for companies — against financial institutions.

“I view our role in some respect as a supplement to regulators,” said Philippe Selendy, chairman of the securities and structured-finance practice. “The way to achieve the best result is to be prepared for the long haul and have clients understand that you may need to litigate for multiple quarters and possibly years.”