(Sharecast News) - German investor sentiment improved less than expected in September, according to a survey released on Tuesday by the ZEW Center for European Economic Research in Mannheim.

The ZEW economic expectations index ticked up to 34.7 from 34.2 in August, but this was below expectations for a reading of 40.0.

The current conditions index rose to -47.1 in September from -61.1 the month before.

ZEW President Achim Wambach said: "The ZEW indicator of economic sentiment remains stable. Experts are cautiously optimistic about a recovery of the economy. The growth continues to be driven by fiscal measures and is further bolstered by export momentum.

"Nevertheless, the risks are considerable: Persistent high energy prices resulting from a continued war in Iran and the additional uncertainty caused by hybrid attacks place a burden on the economy."