Sentix's index for the euro zone climbed into positive territory for the first time in almost a year, reaching 1.3 from -2.7 in December. A Reuters poll had pointed to a reading of 0.7.

The expectations index rose to an all-time high of 33.5 from 29.3 while the current situation index came in at -26.5, its highest level since March and compared to -30.3 in December.

In a statement, Sentix said the overall index reading was surprising given the far-reaching restrictions on economic activity.

"Now that more vaccines have been approved, investors apparently expect a quick implementation of the vaccination strategy and thus a definitive end to the economic and personal freedom restrictions," Sentix said in a statement.

Sentix surveyed 1,168 investors from Jan. 7 to Jan. 9.

(Reporting by Madeline Chambers; editing by Thomas Seythal)