U.S. Senator Elizabeth Warren is calling for U.S. Department of Labor hearings on whether banks accused of rigging foreign exchange markets should be allowed to manage retirement accounts, the Financial Times reported on Sunday. Five of the world’s largest banks, including JPMorgan Chase & Co and Citigroup Inc, were fined some $5.7 billion, and four of them pleaded guilty to U.S. criminal charges over manipulation of foreign exchange rates, authorities said on May 20.