A group of multinational investment banks has been fined €420 million by financial conduct authorities for colluding in the foreign exchange (Forex) spot market. Investigators revealed that currency traders at rival institutions coordinated their trading activities through exclusive online chatrooms. By sharing confidential customer order flows and agreeing on specific trading strategies prior to the setting of key daily benchmark exchange rates (the 'fix'), the traders were able to artificially influence exchange rates to maximize their own trading books' profitability at the expense of clients.
With reference to the extract above, explain what is meant by 'market rigging'.
