The Serious Fraud Office has finally confirmed that it has launched an investigation into currency market manipulation after a number of institutions and individuals were accused of rigging rates.
The SFO confirmed in a statement: "The Director of the Serious Fraud Office has today opened a criminal investigation into allegations of fraudulent conduct in the foreign exchange 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.
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.