Six City brokers have gone on trial, accused of rigging a lending rate used between banks.
The Libor rate is used to carry out trillions of pounds worth of financial deals.
All six men, who have pleaded not guilty, are accused of conspiracy to defraud by trying to move the rate linked to the Japanese yen.
The trial at Southwark Crown Court is set to last 12 to 14 weeks.
The men - Noel Cryan, Darrell Read, Danny Wilkinson, Colin Goodman, James Gilmour and Terry Farr - have been accused by prosecutors of "widespread manipulation" of rates.
They are alleged to have assisted another bank trader called Tom Hayes and others at banks UBS and Citigroup.
Hayes was convicted of rate-rigging in August.
Opening the case for the prosecution, Muhul Chawla QC said all six defendants conspired with Mr Hayes and others and that they were "rewarded in various ways to corrupt the system".