The Barclays rate-rigging scandal is sending shockwaves through world finance, putting ethics and regulation under scrutiny, and raising the prospect of criminal charges in a sector-wide global probe.
Britain's Serious Fraud Office said Friday it will investigate the interbank rate manipulation scandal which has engulfed Barclays, forced three top resignations, tainted the City of London and sparked a political firestorm.
Barclays was fined £290 million ($452 million, 360 million euros) by British and US regulators just over one week ago, for attempted manipulation of Libor and Euribor interbank interest rates between 2005 and 2009.
Barclays became the first bank to be fined as part of a global probe into suspected manipulation of the twin interest rates that are crucial to the operation of short-term financing and global markets.
British lawmakers voted on Thursday to hold a parliamentary investigation into the scandal, instead of a full judicial inquiry.
"This is a multi-bank issue -- albeit evidence and fines for other culpable banks will probably dribble out over a period of many months or years," said Ian Gordon, banking sector analyst at Investec.
"In broad terms, the issue itself and the associated fallout are damaging for the financial sector, both in reputational terms, the costs of investigation and fines -- and any potential redress.
"Moreover, the issue helps to distract from and hence damage any initiatives to increase the flow of lending to the economy, with obvious negative consequences," Gordon said.
BNP Paribas analysts agreed that the crisis had the potential to engulf other lenders.
"As far as we are aware, the regulators have so far not disclosed a full list of banks being investigated," they said in a research note to clients.
They added that "additional fines ... cannot be ruled out, although it's impossible to assess the exact exposures".
Libor (London Interbank Offered Rate) is a flagship instrument used all over the world, affecting what banks, businesses and individuals pay to borrow money. Euribor is the eurozone equivalent.
The Libor rate is calculated daily by data provider Thomson Reuters, on behalf of industry body the British Bankers' Association, using estimates from banks of their own binterbank rates.
Euribor is provided by the Brussels-based European Banking Federation, using data from 43 international banks.
Barclays has admitted that its traders had routinely submitted false readings, as they attempted to benefit their own lucrative derivatives deals.
The lender also posted lower Libor values from 2008 to prevent speculation that it would require a government bailout such as rival groups Lloyds and the Royal Bank of Scotland.
"Barclays attempted to manipulate and made false reports concerning two global benchmark interest rates, Libor and Euribor, on numerous occasions and sometimes on a daily basis over a four-year period, commencing as early as 2005," the Commodity Futures Trading Commission (CFTC) said on June 27.
The US watchdog added that employees at Barclays and its investment bank arm Barclays Capital had sought to boost trading positions to increase profits or minimise losses.
"In addition, the attempts to manipulate included Barclays' traders asking other banks to assist in manipulating Euribor, as well as Barclays aiding attempts by other banks to manipulate US Dollar Libor and Euribor."
Dan Wilsher, senior law lecturer at the City Law School, City University London, told AFP that the scandal raised serious questions over the conduct of some financial sector workers.
"The Libor scandal reveals a lack of honesty amongst dozens of employees -- not just at Barclays -- when the financial rewards are so big for cheating the system, the chances of getting caught slim and the pressure from management is very great," Wilsher said.
"The government will try to make it a crime to give wrong Libor figures but that will be a small step.
"We have not had a broad enquiry into the 'culture' of banking. At the moment the Leveson inquiry is looking at the ethics of the press following numerous scandals. People say we need the same for banking."
The government-appointed Independent Commission on Banking ruled last year that British banks should separate their retail and investment arms to avoid a repeat of the global financial crisis, blamed in part on highly speculative trading practices.
The ICB also recommended that banks substantially increase their capital buffers.
"We have just completed a big ICB review, whose findings the government largely accepted and will pass laws to implement," Wilsher noted.
"This was a technical report on how to protect taxpayers and avoid another crash like that of 2008. It did not address the wider culture in detail but there are many different actions on this front.
"The EU restrictions on bonus payments are an important step in this direction. These need to be adopted globally. The US has introduced bans on trading activities by banks.
"Most importantly, banks need to hold much more capital and become much more risk averse. Hedge funds should take the risks and bear the consequences, not taxpayers."