After years of wondering whether the exit of a small, fiscally weak country like Greece could undermine the euro, policymakers will have to deal with an even bigger shock stemming from the exit of a small, fiscally strong country that is not even a member of the European Union.
Bottom line: we can learn who would benefit and who would be hurt by looking at the Swiss experience, e.g.,
Big Swiss banks fund themselves in Swiss francs, because so many people everywhere want the security of franc assets. They then acquire assets worldwide, in other currencies. When the exchange rate changes abruptly, the banks face large losses – a large-scale version of naive Hungarian homeowners’ strategy of borrowing in Swiss francs to finance their mortgages.
Though the SNB had given many warnings that the euro peg was not permanent, and though it had imposed a higher capital ratio on banks, the uncoupling from the euro came as a huge shock. Swiss bank shares fell faster than the general Swiss index.