Deutsche Bank has been fined $2.5bn (£1.66bn) by regulators in the US and the UK for trying to manipulate interest rates.
The US regulator imposed a $2.1bn fine on the German bank, while the UK City watchdog slapped the bank with a £227m fine.
The fines relate to attempts by the bank to influence the Libor and Euribor interest rates.
Libor – the London interbank offered rate – is a benchmark interest rate that influences how banks set their interest rates. Euribor is similar, but for the euro currency.
At least 29 traders from Deutsche Bank, based across the world, colluded to manipulate the benchmark rates over a period between 2005 and 2009, in an attempt to improve their own trading positions.
In a statement, Deutsche Bank said it had "disciplined or dismissed individuals involved in the trader misconduct" and "substantially strengthened our control teams".
The UK's regulator, the Financial Conduct Authority, said the case "stands out for the seriousness and duration of the breaches by Deutsche Bank – something reflected in the size of today's fine."
"One division at Deutsche Bank had a culture of generating profits without proper regard to the integrity of the market. This wasn't limited to a few individuals but, on certain desks, it appeared deeply ingrained.
"Deutsche Bank's failings were compounded by them repeatedly misleading us. The bank took far too long to produce vital documents and it moved far too slowly to fix relevant systems and controls," the FCA said in a statement.
The regulators released details of email exchanges between traders and submitters, whose submissions provide the information for the benchmark rates to be set.
One of the exchanges read: "Can we have a high 6mth libor today pls gezzer?" "Sure dude, where wld you like it mate?"
Deutsche Bank is just the latest in a series of banks to be fined for manipulating benchmark rates. UBS paid a $1.5bn (£1bn) global settlement in 2012 over rate rigging, while Barclays reached a $453m (£301m) settlement in the same year.