The Serious Fraud Office (SFO) has launched a criminal investigation into allegations of price rigging in the £3tn-a-day foreign exchange market. The probe will look into allegations of "fraudulent conduct", the director of the SFO said in a statement. Around 15 authorities internationally are investigating allegations of collusion and price manipulation. It is alleged that traders used online chatrooms to plan the fixing of benchmark prices. The Financial Conduct Authority (FCA) said in October it had joined other regulators around the world in scrutinising firms over the potential manipulation of the foreign exchange market.