This is the reason the bank gave: In a statement explaining its policy, the SNB points to divergence among major economies; in particular, the weakeni

This is the reason the bank gave: In a statement explaining its policy, the SNB points to divergence among major economies; in particular, the weakening euro which has hit about the lowest level since its inception. With anticipated cash injections by the ECB, the euro is expected to depreciate more against the US dollar and as the franc is pegged to the euro, the Swiss franc is weakening versus the dollar too. So, they conclude that there is no longer "exceptional overvaluation" of the Swiss franc that justified the minimum exchange rate.