Portfolio managers also are uncertain about the direction of oil prices
The worst performers in May were fund indices that track sector-specific categories
The U.S. economy is perking up and consumer confidence is increasing
18 fund indices increased by more than 2%
Portfolio managers point to positive developments in the economies of India and China
U.S. President Donald Trump's pro-business policies also support prices
Foreign equity funds benefit from positive markets, weaker Canadian dollar
But portfolio managers say there are many risks, including the performance of China's economy
The uncertain policies of Donald Trump are key questions
The energy equity fund index was the worst performer