The first financial trader to face prosecution accused of rigging global benchmark interest rates goes on trial in London on Tuesday, following a scandal that handed banks hefty fines and damaged reputations.
Britain's Serious Fraud Office (SFO) alleges Tom Hayes was the ringleader of more than a dozen traders it says worked to rig the London Interbank Offered Rate (Libor) in the mid to late 2000s.
Formerly a trader with Swiss bank UBS and its US rival Citigroup, the 35-year-old Briton will go before the court in Southwark, across the river from London's financial centre in a trial expected to last weeks.
Libor, an estimate of the average interest rate for banks borrowing from other banks, is a key reference for many financial products from consumer loans to savings accounts, and the county will argue that Hayes manipulated it in order to favour his own trades.
Hayes has pleaded not guilty in the case, seen as a test for regulators on whether bankers can be jailed for offences and for the SFO, following a series of blunders and setbacks.
The Libor scandal came to light in 2012 when British bank Barclays was fined £290 million ($448 million, 409 million euros) by British and United States authorities for manipulation.
Since then dozens of traders have been fired and 20 more people charged over manipulation, with a second trial due to start in London later in 2015.
Banks including UBS, RBS and Rabobank have also paid fines, with Germany's Deutsche Bank paying a record total of $2.5 billion for Libor rigging to British and US authorities.
In a further scandal that occurred after a regulatory crackdown on Libor rigging, six major global banks were fined nearly $6 billion, accused of cheating clients by coordinating trades in private chat rooms to manipulate the prices of currencies in exchange markets.