A survey by the ZEW Institute and Credit Suisse Group showed on Wednesday that Switzerland's economic sentiment index plunged to -3.0 in January from 16.6 in December. It was the lowest reading since July 2015.

"Half of the analysts surveyed expect economic growth in Switzerland to stay unchanged. Meanwhile, among the other respondents, the share of analysts who anticipate deterioration exceeds the share of those expecting to see a pickup in economic activity by only three percentage points," the ZEW said.

The current conditions fell to -8.5 in January from -2.7 in December.