At the same time, the number of investors concerned bond market valuations have become stretched has reached a new high in the survey's history. Some 84 percent of the global panel said bonds were overvalued, up from a net 75 percent last month.
Global fund managers were most concerned about valuations in the U.S., with almost 70 percent viewing it as the priciest region in the world.
A bull run for equities is now in its sixth year on the back of extra liquidity provided by several central banks, including the U.S. Federal Reserve.
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The main concern for many in the market is that quantitative easing (QE) may have artificially pushed stocks higher during a period when earnings and data fundamentals were relatively weak.
This bond-buying from QE helped the pan-European FTSE Eurofirst 300 and the Japanese Nikkei 225 hit 15-year highs last week. Meanwhile, German bond yields are seen heading into negative territory and U.S. Treasurys stubbornly remain below 2 percent.
"April's survey offers further proof that global investors are front-running global monetary policy. We are seeing a form of rational exuberance in Europe where a positive view on stocks is supported by fundamentals – but investors no longer believe valuations are cheap," said Manish Kabra, European equity and quantitative strategist, at BAML.