Wall Street stocks have been mostly on a record-setting uptrend and that has raised concerns from C-suite executives tasked with managing a corporation’s money, according to a quarterly survey conducted by Deloitte.

More than 80% of chief financial officers surveyed by accounting firm Deloitte said U.S. stock markets are overvalued, marking the highest level since Deloitte began conducting its quarterly poll about eight years ago.

Overvalued markets are worrying CFOs Source: Deloitte

The findings underline an increasing sense of dread by market participants that stock valuations have become bloated after the S&P 500 index SPX, -1.11% , the Dow Jones Industrial Average DJIA, -0.87% and the Nasdaq Composite Index COMP, -1.07% have registered repeated records and remain less than a percentage point from fresh records in recent trade.

The Dow has rung up 42 all-time highs in 2017, the S&P 500 index has booked 37 records, while the Nasdaq has ended at a record 49 times, so far this year.

Fretting about stock-market valuations isn’t new. According to a July study by StarCapital Research, the U.S. has the least affordable equity market in the world.

Majority of Wall Street CFOs believe this stock market is "bubblicious"

A mounting chorus of industry participants worrying about inflated equity values doesn’t mean that stocks will experience a pronounced downdraft soon, but it does raise the question about the level of returns investors can expect to see as the market creeps higher, and as volatility, as measured by the CBOE Volatility Index VIX, +15.91% , or VIX, remains at a subdued level of 10. That represents around its lowest levels in history and way below its historic average around 20.

Read: Opinion: A bear market could hit U.S. stocks any time now

MarketWatch’s Mark Hulbert warns that when stocks become elevated, it doesn’t take much to tip them over the edge into a sharp fall, with seemingly no external triggers. That’s not to mention all the genuine external tensions abounding. Those include elevated antagonism between the U.S. and North Korea, which recently threatened to detonate a hydrogen bomb in the Pacific Ocean this weekend, and a Federal Reserve attempting a historic right-sizing of its asset portfolio even as its leader has described stubbornly low levels of inflation a “mystery.”

MarketWatch’s Ciara Linnane points out that the Deloitte survey is part of a broader decline in Wall Street optimism about the market and the economic outlook, with net optimism tumbling to 29% in the third quarter from 44% in the second quarter. Paralysis in Washington, after markets roared higher on hopes that President Donald Trump would enact pro-market policies, also has been a factor behind dwindling hopes.

To be sure, not everyone is in a dour mood about markets. Laszlo Birinyi, who accurately forecast that the S&P 500 would hit 2,500 by September, thinks the stock market has more room to run before 2017 is over.

The longtime bull attributes his outlook to the belief that market enthusiasm remains pessimistic, which he thinks is a contraindicative signal. He theorizes that the more exuberance swirling around in the market, the greater the likelihood of a sudden unexpected downturn, with an abundance of pessimism likely decreasing the chance of stumbling into a sharp selloff.