A scandal over interbank rate rigging focused on the LIBOR reference rate could cost 11 banks, including Barclays Bank, around 12 billion euros ($14.7 billion), a Morgan Stanley study said Friday.
The study only looked at 11 of 18 banks that set the London Interbank Offered Rate (LIBOR) in dollars each day, and did not explain why the other seven were not included.
Morgan Stanley, a US-based investment bank, estimated that each of the 11 banks under consideration would be fined a comparable amount, with the exception of Barclays, which would benefit from having reached an agreement with regulatory authorities before the others.
The total amount in fines, including the one to be paid by Barclays, was tipped to amount to 5.67 billion euros.
But Morgan Stanley also forecast additional costs stemming from the affair of around 6.38 billion euros.
LIBOR is a flagship instrument used all over the world, affecting what banks, businesses and individuals pay to borrow money.
The LIBOR rate is calculated daily by data provider Thomson Reuters, on behalf of the British Bankers' Association using estimates from banks of their own interbank rates.
Barclays was already fined £290 million ($452 million, 360 million euros) by British and US regulators for attempted manipulation of LIBOR and EURIBOR, its euro equivalent, between 2005 and 2009.
Three senior executives, including the bank's chairman and its chief executive, have resigned to acknowledge their share of responsibility in the matter.
Britain's House of Commons is to set up a parliamentary investigation of the affair and the Serious Fraud Office is to launch a criminal probe.
In Brussels, the European Commission has said it will investigate all key rates on interbank markets.
In the United States, the Congress plans to question Treasury Secretary Timothy Geithner and Federal Reserve Chairman Ben Bernanke later this month about the bank-rigging scandal, which threatens to spill over from London to Washington.