The Swiss Market Index of leading blue chip companies has fallen below 5,000 points for the first time in over five years.
The SMI closed at 4,941.31 points on Tuesday, a drop of 2.7 per cent compared to Monday's close and about 11 per cent lower than at the start of the year.
Almost all of the index's 20 reference stocks were down, with insurer Swiss Life suffering the biggest drop of 13 per cent.
Switzerland's biggest banks Credit Suisse and UBS lost 6.5 per cent and 5.5 per cent respectively.
The last time the SMI stood below 5,000 points was in the summer of 2003.