Six financial brokers, including a New Zealand resident, accused of trying to fix an international bank lending rate helped a trader "cheat" as part of a "dishonest scheme", a court has heard.
The men were "willing and enthusiastic" in the way they acted to "corrupt a process that should not have been corrupted", the jury was told at the trial in London.
Darrell Read, a 50-year-old Briton who worked for UK-based brokers ICAP in Wellington, Noel Cryan, Danny Wilkinson, Colin Goodman, James Gilmour and Terry Farr, are accused of conspiracy to defraud by trying to manipulate the Libor (London Interbank Offered Rate) linked to the Japanese yen.
Libor is the term for benchmark rates that underpin hundreds of trillions of pounds worth of contracts from mortgages to corporate lending.
It is claimed the men conspired with Tom Hayes, a former Tokyo-based trader for UBS who later joined Citigroup, and others, to manipulate the Libor rate in offences alleged to have taken place between August 2006 and September 2010.
The jury was told Hayes was convicted of conspiracy to defraud earlier this year.
Prosecutor Mukul Chawla QC said the case is about the dishonest and wide scale manipulation of bank rates for profit and the defendants agreeing to interfere and abuse a critical financial process.
He told the jury the defendants did this to assist a trader at a bank to "cheat" other traders.
"That cheating enabled the trader to make literally millions of pounds for the banks," Mr Chawla said.
He said the six defendants were essentially helping Hayes to "cheat" those who had entered into trades with him.
"Each of these six defendants were brokers, middle men, willing and enthusiastic to lend themselves to Mr Hayes' dishonest scheme," Mr Chawla told the jury.
The court heard that Read was known as Big Nose while Goodman's nickname was Lord Libor.
The trial at Southwark Crown Court, London, is not set to finish until the new year.