Europe’s banks, sitting on $1.19 trillion of debt to Spain, Portugal, Italy and Ireland, are facing a wave of losses if Greece abandons the euro.

While lenders have increased capital buffers, written down Greek bonds and used central-bank loans to help refinance units in southern Europe, they remain vulnerable to the contagion that might follow a withdrawal, investors say. Even with more than two years of preparation, banks still are at risk of deposit flight and rising defaults in other indebted euro nations. Enlarge image UBS, the third-biggest manager of money for the wealthy, sees a 20 percent chance of Greece leaving the euro within six months, the bank’s chief investment office, led by Alexander Friedman, told client advisers in an internal note last week., Europe’s biggest bank by assets, tapped “a small amount” of ECB cash to help fund corporate and retail business in continental Europe, where it has sizeable operations in Italy and Spain. Photographer: Hannelore Foerster/Bloomberg “A Greek exit would be a Pandora’s box,” said Jacques- Pascal Porta, who helps manage $570 million at Ofi Gestion Privee in Paris, including shares in Deutsche Bank AG (DBK) and BNP Paribas SA. (BNP) “It’s a disaster that would leave the door open to other disasters. The euro’s credibility will be weakened, and it would set a precedent: Why couldn’t an exit happen for Spain, for Italy, and even for France?” The prospect of Greece leaving the 17-nation euro region increased after parties opposed to the terms of the nation’s second bailout by the European Union and the International Monetary Fund won most of the votes in May 6 elections. A fresh round of voting will be held June 17 after politicians failed to form a government. For the first time since the crisis began in November 2009, European leaders and central bankers are speaking openly of Greece abandoning the currency union. Deposit Flight The immediate risk for Europe’s banks, and for the euro region, would be a deposit flight from indebted nations such as Portugal, Ireland, Spain and Italy on speculation those countries also might quit the currency. Lenders in Germany, France and the U.K. had $1.19 trillion of claims on those four nations at the end of 2011, Bank for International Settlements data show. Should Greece go, its new currency probably would suffer an immediate devaluation of as much as 75 percent against the euro, forcing individuals and companies to default on foreign loans, economists at UBS AG (UBSN) said. Unless European leaders could make a credible case that a Greek exit was an exceptional and isolated incident, depositors in other nations might decide to withdraw euros from banks or shift them to countries seen as safer. “The highest risk facing the banks at the moment is the possibility of deposit runs,” said Andrew Stimpson, a banking analyst at Keefe, Bruyette & Woods Ltd. in London. “The more policy makers continue to openly discuss an exit, the more likely that people in Spain, Ireland and Portugal pull money out of their local banks.” Greek Withdrawals That already may be happening. Banks in Greece, Ireland, Italy, Portugal and Spain saw a decline of 80.6 billion euros ($103 billion), or 3.2 percent, in household and corporate deposits from the end of 2010 through the end of March, European Central Bank data show. Lenders in Germany and France saw an increase in deposits of 217.4 billion euros, or 6.3 percent, in the same period. Greek central bank head George Provopoulos told President Karolos Papoulias last week that savers have withdrawn as much as 700 million euros and the situation may worsen, according to the transcript of the president’s meeting with party leaders published May 15. Greece had 160 billion euros of bank deposits on March 30, down almost 75 billion euros from the peak in 2009, according to the latest data from the central bank. Greece’s pledge to inject 18 billion euros of capital in the nation’s banks may help staunch the outflow in deposits. The Hellenic Financial Stability Fund said late yesterday it approved terms of the recapitalization and the contract would be sent today to the lenders and the European Financial Stability Facility for final approval.