IN THE world of central banking, slow and predictable decisions are the aim. So on January 15th, when the Swiss National Bank (SNB) suddenly announced that it would no longer hold the Swiss franc at a fixed exchange rate with the euro, there was panic. The franc soared. On Wednesday one euro was worth 1.2 Swiss francs; at one point on Thursday its value had fallen to just 0.85 francs. A number of hedge funds across the world made big losses. The Swiss stockmarket collapsed. Why did the SNB provoke such chaos? The SNB introduced the exchange-rate peg in 2011, while financial markets around the world were in turmoil. Investors consider the Swiss franc as a “safe haven” asset, along with American government bonds: buy them and you know your money will not be at risk. Investors like the franc because they think the Swiss government is a safe pair of hands: it runs a balanced budget, for instance. But as investors flocked to the franc, they dramatically pushed up its value. An expensive franc hurts Switzerland because the economy is heavily reliant on selling things abroad: exports of goods and services are worth over 70% of GDP. To bring down the franc’s value, the SNB created new francs and used them to buy euros. Increasing the supply of francs relative to euros on foreign-exchange markets caused the franc’s value to fall (thereby ensuring a euro was worth 1.2 francs). Thanks to this policy, by 2014 the SNB had amassed about $480 billion-worth of foreign currency, a sum equal to about 70% of Swiss GDP.

The SNB suddenly dropped the cap last week for several reasons. First, many Swiss are angry that the SNB has built up such large foreign-exchange reserves. Printing all those francs, they say, will eventually lead to hyperinflation. Those fears are probably unfounded: Swiss inflation is too low, not too high. But it is a hot political issue. In November there was a referendum which, had it passed, would have made it difficult for the SNB to increase its reserves. Second, the SNB risked irritating its critics even more, thanks to something that is happening this Thursday: many expect the European Central Bank to introduce “quantitative easing”. This entails the creation of money to buy the government debt of euro-zone countries. That will push down the value of the euro, which might have required the SNB to print lots more francs to maintain the cap. But there is also a third reason behind the SNB’s decision. During 2014 the euro depreciated against other major currencies. As a result, the franc (being pegged to the euro) has depreciated too: in 2014 it lost about 12% of its value against the dollar and 10% against the rupee (though it appreciated against both currencies following the SNB's decision). A cheaper franc boosts exports to America and India, which together make up about 20% of Swiss exports. If the Swiss franc is not so overvalued, the SNB argues, then it has no reason to continue trying to weaken it.

The big question now is how much the removal of the cap will hurt the Swiss economy. The stockmarket fell because Swiss companies will now find it more difficult to sell their wares to European customers (high-rolling Europeans are already complaining about the price of this year’s skiing holidays). UBS, a bank, downgraded its forecast for Swiss growth in 2015 from 1.8% to 0.5%. Switzerland will probably remain in deflation. But the SNB should not be lambasted for removing the cap. Rather, it should be criticised for adopting it in the first place. When central banks try to manipulate exchange rates, it almost always ends in tears.

Dig deeper:

A referendum to boost Switzerland's gold reserves (November 2014)

The market reaction to the SNB's decision (January 2015)

The impact on Central Europe (January 2015)