The Federal Reserve is investigating whether traders at the world’s biggest banks rigged benchmark currency rates, raising the risk that firms will be penalized for lax controls as regulators look for wrongdoing. The Fed, which supervises U.S. bank holding companies, is among authorities from London to Washington probing whether traders shared information that may have let them manipulate prices in the $5.3 trillion-a-day foreign-exchange market to maximize their profits, said a person with direct knowledge of the matter, asking not to be named because it’s confidential. “The Fed has discretion whether to and how ... (full story)