The financial giant JPMorgan Chase continues to suffer losses on the risky derivatives trade that initially cost the company at least $2 billion. JPMorgan has now lost an additional $1 billion since the loss was disclosed a week ago. Meanwhile, a group of shareholders have filed a class action lawsuit accusing bank executives of misleading investors about the loss. The suit accuses JPMorgan of failing to properly disclose the risks involved in the firm’s trades. The Justice Department is now probing JPMorgan amid new calls for tougher regulation of Wall Street.