The accusation, known as a statement of objections in EU jargon, does not prejudge the outcome of an investigation, but are rarely reversed and the accused can expect fines. "The commission's investigation relates to certain traders at eight banks and does not imply that the alleged anti-competitive conduct was a general practice," the EU said.
The Brussels-based commission refused to name the banks, but a banking source said that US giant Bank of America Merrill Lynch was one of the eight. The US bank declined to comment.
The case comes a month after Credit Suisse, Credit Agricole and Deutsche Bank came into the EU's crosshairs for bond trading collusion in a separate case announced in December. Credit Suisse was also targeted by Brussels over a foreign-exchange cartel last year.
The EU probe follows a similar probe last year in London by British regulators into a suspected cartel among bond-traders at unnamed international banking giants.