Professional investors are starting to worry that stock prices are getting out of hand compared with where they should be.

Valuation has been a key concern of late for market participants in a bull market that just passed its eighth anniversary. The now trades at 18.3 times forward earnings — the 12-month period ahead — which marks the highest level since the market turned around after the financial crisis.

In the latest Bank of America Merrill Lynch fund manager survey, a net 34 percent of respondents find that equities are overvalued. That's the highest level in the history of the survey going back 17 years.

On top of that, a net 81 percent believe that the U.S. is the "most overvalued region" compared with other areas of the world.

"Investor positioning argues for a risk rally pause in March/April, with allocation to equities at a two-year high and bond allocation at a three-year low," Michael Hartnett, BofAML's chief investment strategist, said in a statement issued the same day that major averages slid amid a sharp sell-off in bank stocks.

However, that's the bad news. The good news is that even while valuation is a concern, managers seem to have little fear of a bear market popping up anytime soon despite worries over a "pause."