The business confidence index fell to +6.9 points from +10.5 points.
The gauge of sentiment in the industrial sector "barely fell" and continued to reflect optimism, GKI said. However, production outlooks and assessments of inventories worsened. Order stocks were higher, although export orders declined.
In the construction sector, sentiment returned to March levels. Companies in the buildings segment were a little more optimistic, while sentiment in the civil engineering segment soured. Assessments of output in the previous three months improved but worsened for order stocks.
Sentiment in the commerce sector improved "with tiny steps" for the third month in a row. Assessments of sales positions improved "significantly", but the outlook for orders and inventories worsened.
Confidence in the service sector saw an "enormous" decline in May, but was still over March levels.
GKI's consumer confidence index fell to -29.5 points in May from -20 points in April. Households gave worse assessments of their own financial situations and fewer said they could make savings. Fewer households also said they planned to make big-ticket purchases.
GKI's gauge of business and consumer confidence is supported by European Union funding.



