The Swiss franc has soared some 30% in chaotic trade as the central bank abandoned the country's cap on the currency's value against the euro.
The Swiss National Bank said the cap, introduced in Sept. 2011, is no longer justified.
At the same time it reduced a key interest rate from -0.25% to -0.75%, increasing the amount investors have to pay to hold Swiss deposits.
Following the SNB move the Swiss franc went from 1.20 to the euro to 0.8052.
Swiss shares fell some 6% and stock markets around Europe fell with investors buying "safe haven" assets such as gold and German bonds.
One trader described trading after the unexpected announcement as "carnage".
http://www.bbc.co.uk/news/business-30829917