An overwhelming majority of the world's asset managers think stocks are overvalued and expect a recession this year or in 2021, according to a survey released Wednesday by the Boston Consulting Group.

Many say "the current bull market is running on borrowed time."

Why it matters: The survey of more than 250 asset managers and analysts who oversee $300 billion at firms that collectively manage over $10 trillion shows the continued apprehension of investors from around the globe.

"The survey, conducted in November and December 2019, found that, on average, respondents’ outlook is similar to what it was just before the market correction in late 2018."

Even with stocks racing higher into the end of 2019, market sentiment was "nearly identical to what we found in our 2018 survey when we saw a clear shift in sentiment from bullish to bearish."

Expand chart Data: BCG 2014-2019 investor surveys; Chart: Danielle Alberti/Axios

Background: The S&P 500 has gone the longest amount of time in history without a 20% decline, or bear market, and that has a lot of money managers anxious — expecting that the good times cannot last forever.

BCG's survey also finds that worries about geopolitical uncertainty are adding to these fears as are the political environment and the upcoming U.S. presidential election.

Details: The stock market's historically high price-to-earnings ratio is the top concern, investors say.

73% of respondents say they see markets as currently overvalued, up from 67% in the 2018 survey.

Among self-described market bears in the 2019 survey, 78% cited market overvaluation as the reason for their pessimism, versus 64% in the 2018 survey.

One level deeper: Fear that U.S. equities are headed for consistently weaker performance is gaining steam, with investors' expectations for total return falling to a record low of 5.6% — well below the average 10.1% annual total stock return of the S&P 500 since 1926.

Despite the S&P far outpacing these levels in three of the last four years, the expected return of 5.6% "roughly matches the expectation level reported in our previous three surveys," BCG analysts say in the report.

Yes, but: "Although many investors believe that the current bull market is running on borrowed time, few anticipate a major market crash or deep recession," the survey notes.

The 71% of respondents expecting a recession in the next two years is down from 74% in the 2018 survey.

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