The Swiss Market Index (SMI) of 20 leading companies tumbled nearly eight per cent on Friday – the worst drop in 17 years.
The result is in line with other European markets as investors dumped equities amid fear that efforts by governments and central banks to breathe new life into credit markets may not prevent a recession.
The SMI closed at 5,347 points, down 22 per cent over the week.
Shares of dental implant maker Nobel Biocare slumped more than 26 per cent, while the Credit Suisse bank dived 16 per cent.
The pan-European benchmark, FTSEurofirst, fell 7.8 per cent – its lowest close in more than five years.
Experts say investors across asset classes are awaiting the outcome of meetings in Washington, involving Group of Seven finance ministers and central bankers, and the International Monetary Fund (IMF).