A customer is served at a counter inside a foreign exchange store displaying a poster of various banknotes including the Chinese yuan or renminbi (RMB) in Hong Kong November 20, 2009.
Banks were accused of rigging forex markets (Reuters)

Five global banking giants, including British banks Barclays and Royal Bank of Scotland, have been slapped with record fines totalling $5.7bn (£3.7bn, €5.1bn) for rigging foreign exchange markets.

Barclays, RBS, Citigroup and JP Morgan all submitted guilty pleas to the US Department of Justice. UBS was granted immunity in the current probe for being the first to cooperate with antitrust investigators, although it did plead guilty to charges related to interest-rate manipulation.

It marks the second set of fines for fixing forex markets after six banks were fined £2.6bn in November 2014. The global foreign exchange market is worth £3.5tn a day. Meanwhile, Barclays said it would fire eight individuals as part of a deal with the US regulator.

The banks were accused of fixing benchmark foreign exchange rates by colluding in online chat rooms to make transactions simultaneously minutes before rates were set, according to the DoJ.

Mark Taylor, a former foreign exchange trader and Dean of Warwick Business School, said: "The fact these fines are so big and this has been investigated so thoroughly demonstrates just how serious the collusion and price fixing was, and how low confidence in the banks has sunk.

"A shift in culture is necessary in order to ensure that something similar doesn't happen in another guise. Imposing heavy penalties - together with the accompanying adverse publicity - is one way of shifting that culture."