The world economy needs more productive investment and less in speculative assets, which in many cases are now overvalued and pose big stability risks, the International Monetary Fund said Wednesday.

Jose Vinals, the IMF's top financial counsellor, said that not enough of the easy money pumped into economies by advanced countries' central banks is going into economic activities that support growth.

Instead, too much is going into financial risk-taking that poses challenges to global financial stability, he said, unveiling the IMF's newest assessment of financial risks in the world economy.

"More than six years after the start of the financial crisis, the global economy continues to rely heavily on accommodative monetary policies in advanced economies."

"But the impact has been too limited and uneven," he said.

The loose monetary policies of the Federal Reserve, and central banks in Europe and Japan, have spurred some investment in activities that create jobs and spur production and consumption, Vinals acknowledged.

But too much has moved into assets and other speculation, which could backfire on growth if a sell-off is triggered.

Vinals said the world economy is at risk from "the buildup of certain excesses in financial risk taking." Many assets are "richly valued" and "way out of line from fundamentals."

In addition, a lot of risk capital has flowed into emerging-market economies -- $4 trillion in their equities and bonds -- that are more vulnerable to sharp shifts in the direction of flows.

"All of this has the potential of decompressing," Vinals said.

Two issues, he said, that could turn the tide and set back growth are a rise in the tensions in the Russia-Ukraine crisis, and a poorly implemented tightening of monetary policy by the Federal Reserve.

Just beginning to "normalize" its easy-money policies of the past six years, the Fed needs to "be mindful of the repercussions for the rest of the world," Vinals cautioned.

"Shocks from advanced economies have the potential to more quickly propagate in emerging markets."