The Swiss currency has hit its highest ever level against the US dollar.
The dollar dropped to 94.5 Swiss centimes over lunchtime on Tuesday - an all-time low - before recovering slightly.
The US currency fell against most major currencies on Tuesday following weak housing and consumer confidence data.
The Swiss franc has risen against both the dollar and the euro ever since the 2008 financial crisis, thanks to its status as a safe haven within Europe.
Against the euro, the Swiss franc was trading slightly below its all time high of 80.35 euro cents, set just before Christmas.
Markets perceive the country as being a safe place to park cash, free of the debt worries that afflict some countries in the eurozone and - to a lesser extent - the UK.
The Swiss government is running a modest budget deficit in comparison to its European peers, while the country as a whole enjoys a big trade surplus with the rest of the world.
The franc has played a similar role to the Japanese yen - another currency that has proved a safe haven in the past two years, much to the chagrin of its government.
Like the Japanese, the Swiss intervened to weaken their currency earlier this year, fearing that a rapid rise would make its exports uncompetitive.
But - just like the Japanese government - the Swiss National Bank eventually gave up the effort in the face of an inexorable inflow of private money into its home currency.