Swiss bank UBS agreed today to pay £940 million to regulators in the biggest penalty yet from the industry's Libor-rigging scandal.
The settlement, which includes a record fine of £160 million from the UK's Financial Services Authority, is far larger than the total of £290 million paid by Barclays for Libor manipulation this summer.
The Zurich-based bank, which has around 6,500 staff in London, has endured a turbulent year after the jailing of rogue trader Kweku Adoboli.
The FSA said the misconduct was "extensive and widespread" as UBS's traders routinely made requests to colleagues responsible for determining Libor and Euribor submissions in an effort to benefit their own trading positions.
It said that at least 45 individuals including traders, managers and senior managers were involved in, or aware of, the practice. The regulator recorded at least 2,000 requests for inappropriate submissions and said many more would have been made orally.
Tracey McDermott, FSA director of enforcement and financial crime, said: "They manipulated UBS's submissions in order to benefit their own positions and to protect UBS's reputation, showing a total disregard for the millions of market participants around the world who were also affected by Libor and Euribor."
As well as the FSA, the US Department of Justice and UBS's main Swiss supervisor were among those involved in today's settlement.
Libor is the umbrella term for benchmark rates that underpin the terms of $500 trillion of contracts from mortgages to the cost of corporate lending.
The probe, which has embroiled about 20 financial institutions, has accelerated with the first arrests by the Serious Fraud Office taking place last week.
Taxpayer-backed Royal Bank of Scotland has previously said it hopes to settle any claims over Libor manipulation soon and warned that potential penalties could be significant.
The FSA said misconduct at UBS was "all the more serious" as it had attempted to manipulate Libor submissions at other banks, making corrupt payments to reward brokers for their efforts.
Today's report from the FSA revealed incriminating conversations between UBS traders and brokers, saying they would "play the rules" and "return the favour".
One trader said: "I need you to keep it (the six-month Japanese Libor rate) as low as possible... if you do that... I'll pay you, you know, $50,000, $100,000... whatever you want... I'm a man of my word."
Bankers referred to each other in congratulatory terms, such as "the three muscateers (sic)", "Superman", and "Captain caos (sic)", according to the FSA.
Sergio Ermotti, chief executive of UBS, said the group had "taken decisive and appropriate actions" following the probe.
He added: "We deeply regret this inappropriate and unethical behaviour.
"No amount of profit is more important than the reputation of this firm, and we are committed to doing business with integrity."
As well as the FSA, UBS said it had also agreed to pay $1.2 billion (£740 million) in fines to the US Department of Justice and the Commodities Futures Trading Commission, and 59 million Swiss francs (£40 million) to the Swiss Financial Market Supervisory Authority.
The bank also admitted to committing wire fraud through its office in Japan relating to rate manipulation.
UBS said the fines were likely to see it report a loss of around 2 billion to 2.5 billion Swiss francs (£1.3 billion to £1.7 billion) for the fourth quarter.