The Serious Fraud Office is tipped to imminently launch an investigation into banks and individuals accused of rigging foreign exchange rates.

According to a range of media reports, the SFO will announce the probe by the end of July.

However, the SFO has not formally confirmed or denied the launch of the investigation but instead repeated a statement it made to IBTimes UK before: "We are receiving and examining complex data on this topic. If and when we open a criminal investigation, that decision will be announced."

The FX Market

The daily $5tn (£3.1tn, €3.7tn) currency market is the largest in the financial system and is pegged to the value of funds, derivatives and products.

Morningstar estimates that $3.6tn in funds, including pension and savings accounts, track global indexes.

FX rates are calculated and compiled by using data from a variety of submitted provisions on a number of platforms, such as ThomsonReuters.

It is then calculated by WM, a unit of State Street, to form WM/ThomsonReuters at 1600 GMT daily.

Previously, IBTimes UK exclusively revealed that a whistleblower alerted regulators in the US, UK and Switzerland in 2011 to some of the world's largest trading companies and banks manipulating benchmark sterling, US dollar and Swiss franc currency rates.

However, it was not until 2013 that these authorities started investigating allegations of market rigging.

Meanwhile, US, Asian, and UK authorities are investigating a number of banks into FX rigging allegations.

This month, the Royal Bank of Scotland's (RBS) boss Ross McEwan said on a radio show that he believes that FX fixing fines could massively exceed those imposed on Libor rigging cases.

A number of banks are already under close scrutiny after over 20 high-ranking FX traders have left their jobs at a raft of different lenders since the probes began.

All the banks all declined to say whether these departures were related to the investigations or have stated that the bankers were exiting for unrelated reasons.

UBS' share price was recently hit after a study claimed that it could end up with an $8bn (£4.7bn, €5.9bn) bill all in if it is found to have committed wrongdoing under the various regulatory probes across the world into suspicions of currency market rigging.