LONDON (AP) — More global banks are being investigated for the alleged financial market manipulation that led to fines of $453 million against Barclays Bank, British Treasury chief George Osborne said Thursday, driving financial stocks lower.
The day before, U.S and British regulators fined Barclays for manipulating the interest rate — the London interbank offered rate (LIBOR) — to its advantage between 2005 and 2009. The rate is used to price mortgages and consumer loans.
Osborne said Barclays was not the only bank to be involved in market fixing.
"HSBC and RBS are two of the banks under investigation but there are also international banks like UBS and Citigroup who are also under investigation partly for the activities conducted in this country," he said.
He didn't specify which were being investigated in Britain. Citigroup spokesman Steven Blaney said the bank was not being investigated by Britain's Financial Services Authority.
Barclays chief executive Bob Diamond, who is facing calls to resign, acknowledged that the bank had failed to meet "the high standards that we set for ourselves."
Osborne said Barclays was not the only bank to be involved in market fixing. Beyond the U.K., there are also investigations in several countries involving numerous global banking groups.
The banks' share price fell sharply as investors expected hefty fines and tighter regulation. Barclays shares closed down 15.5 percent, RBS 11.5 percent, HSBC 2.6 percent and Lloyds Banking Group 3.9 percent.
The Financial Services Authority cited evidence that Barclays traders were, in some cases, in touch with people in other banks.
"Banks were clearly acting in concert," said Andrew Tyrie, a British lawmaker who chairs the influential Treasury Committee in the House of Commons. "I fear it's not going to be the end of the story, that we are going to find that other banks have been involved."
Tyrie said his committee would summon Diamond to explain what happened at the bank.
In a letter to Tyrie, Diamond said he would be happy to attend.
"I appreciate that the nature of the settlements disclosed yesterday raises many questions," Diamond wrote. But, he added, "the principal message is simple: Barclays' actions did not meet the high standards that we set for ourselves."
Though Diamond has decided to waive his 2012 bonus in the wake of the fines, he's facing calls to step down.
"If Bob Diamond had a scintilla of shame, he would resign," said Matthew Oakshott, a member of the House of Lords. "If Barclays' board had an inch of backbone between them, they would sack him."
Prime Minister David Cameron, when asked whether Diamond should resign, said he thinks "the whole management team have got some serious questions to answer. Let them answer those questions first."