The Swiss Franc is the sixth most-traded currency on the planet, and it exploded in value this morning by 15 percent.

That’s because the Swiss National Bank surprised just about everyone when it stopped trying to control the currency.  It had been holding the currency down in value starting in 2011 during the eurozone crisis.  Investors at the time, fleeing the instability of the euro, sought to put their money in Switzerland.  That bid up the price of Swiss francs, hurting exporters.

The Swiss National Bank had printed nearly half a trillion Swiss francs in its effort to buy up other currencies and devalue the franc.  The bank called it quits without explaining its decision.  Perhaps it was concerns over inflation or public pressure, or fears that all the investments it was making were exposing it to undue risk.  Whatever the reason, the effect was immediate.