Switzerland’s notorious Swiss franc crisis, which rocked markets one year ago and sent the currency spiking, could return to haunt traders, some analysts warn. The nation’s central bank stunned foreign exchange and other financial markets on January 15, 2015, when it unexpectedly scrapped efforts to stop the franc rising against the European single currency. The Swiss National Bank (SNB) decided to abandon the minimum rate of 1.20 francs against the euro that it had been defending for more than three years.