The State Street Global Investor Confidence Index declined slightly in June by 1.6 points to 101.
A reading of 100 on the index is 'neutral', which means that on a global basis institutional investors remain in 'risk on' territory.
The June reading showed that confidence among both Asian and North American investors declined, with the Asian index down 4.4 points to 97.1, and the North American reading falling 2 points to 102.2.
The European index, on the other hand, increased by 1.7 points from 96.8 to 98.5.
State Street Associates' Kenneth Froot, who developed the index with his colleague Paul O'Connell, said the optimism of May among investors did not continue in June.
"Even in North America, while the index remains in a ‘risk-on’ territory, the decline in investor confidence was likely driven by intensified concerns around overvaluation, oil prices and the US energy policy, as the [US Federal Reserve] delivered its second rate hike in 2017," Mr Froot said.
State Street global markets head of macro strategy Timothy Graf said, "Sentiment remains rather subdued across regions as investors do not appear to enthusiastically endorse the steady climb of risky asset valuations.
"The neutral read on investor behavior disproves the notion of market complacency in the face of many latent risks."
Equity Trustees hires BNP Paribas US CEO
Future Fund restructures, property head departs
AMP appoints John O’Sullivan to board
Is this as good as it gets?
Renewables will drive next industrial revolution
China's MSCI inclusion has room to grow