An appeals court has revived allegations that a former Bingham McCutchen lawyer acted in bad faith by withholding evidence that would have supported investor claims against the firm’s client Merrill Lynch & Co Inc. Bingham’s opposing counsel said in an interview that the ruling could put the firm on the hook for a large monetary sanction.

Bingham defended a broker-dealer unit of Merrill Lynch against allegations that it aided and abetted an alleged embezzlement scheme by Connecticut tax attorney Daniel Carpenter. Carpenter’s clients argue that former Bingham lawyer John Snyder (now of Nutter McClennen & Fish) improperly shielded documents that bolstered the aiding and abetting allegations.