An eventful summer and poorer than expected earnings spooked US investors as the global investor confidence index (ICI) dropped 8.3 points to 89.7 in August, according to the latest State Street ICI.
The North American sentiment fell 10.3 points to 89.5, while European sentiment fell 5.6 points, and Asian sentiment fell two points to 106.1.
Co-developer of the index, Kenneth Froot, said poorer than expected earnings took the wind out of US institutional investors' sails and pushed the US ICI deeper into the red.
"As the August ICI reading was taken before Janet Yellen's speech at Jackson Hole, it remains to be seen whether her growing conviction on the case for a rate hike will mark a further round of risk aversion," Froot said.
State Street head of macro strategy, EMEA, Timothy Graf, said the recent "melt-up" in risky asset valuation did not appear to be endorsed by institutional investors.
"The exception to this would be the resilient sentiment we see in Asia, perhaps a reflection of receding fears of a hard landing in China," Graf said.