The Swiss franc strengthened against all major currencies last month. The economics ministry said the franc was up on average 1.8 per cent over its value in November.
The biggest gain was made against the Japanese yen (plus 8.4 per cent), but there were also above average gains against the dollar (plus 5.3 per cent) and against the British pound (plus 2.8 per cent).
The ministry said on Saturday the franc had made much more moderate gains against the common European currency. The Swiss currency was 0.5 per cent stronger against the euro in December than the previous month.
Taking a longer-term view, the franc is up by 2.7 per cent compared to its value one year ago against the currencies of Switzerland's 15 main trading partners.
The economics ministry said the Swiss currency had been "remarkably stable" against the euro in 1999 and in the first quarter of 2000, but had strengthened progressively since then.
swissinfo with agencies