Trader David Berry’s victory in a battle against market regulators may also hand him a weapon in his next fight, when his $100-millon wrongful dismissal suit against Bank of Nova Scotia goes to trial in 2015.

Mr. Berry was let go by Bank of Nova Scotia in 2005, at the same time as regulators were looking into his trading of preferred shares, a market he dominated on his way to annual pay packages worth $15-million. He launched the wrongful dismissal suit the next year, seeking lost compensation and damages. Mr. Berry alleges in his claim that the bank tipped regulators to a potential breach, then fired him over what was really a pay dispute stemming from his refusal to accept changes the bank sought that would have cut his compensation.