Four major banks agreed to plead guilty on Wednesday to trying to manipulate foreign exchange rates and six were fined nearly $6 billion (4 billion pounds) in yet another settlement in a global probe into the $5-trillion-a-day market. Authorities in the United States and Britain accused traders at Citigroup (C.N), JP Morgan (JPM.N), Barclays (BARC.L), UBS (UBSG.VX) and Royal Bank of Scotland (RBS.L) of brazenly cheating their clients to boost their own profits using invitation-only chatrooms and coded language to coordinate their trades. The misconduct occurred up until 2013, after regulators had started punishing banks for rigging the London interbank offered rate (Libor), an interest rate benchmark, and banks had pledged to overhaul their corporate culture and bolster compliance. Reuters