By Matt Egan, CNN Business

(CNN) -- Republicans and Democrats might not agree on much these days, but there's a consensus forming among partisan investors: the bull market is running low on time.

Fifty-three percent of Republican investors say the bull market will end within the next two years, according to an E*Trade survey shared exclusively with CNN Business on Thursday.

The survey, taken during the days after the midterm election, found that an identical 53% of Democrat investors anticipate a bear market within the next two years.

"It is the lone area where we see similar sentiment across the aisle," Mike Loewengart, E*Trade's vice president of investment strategy, said in an interview. "We're coming off this nine-year plus run. Investors recognize that it's not going to last forever."

Just one in three investors surveyed said the bull market will last three or more years.

Democrats tilted more bearish, but only slightly so. One in four say the end is near, compared with 17% of Republican investors. And 53% of Democrats said market volatility will increase as a result of the US midterm elections, compared with 43% of Republicans.

The E*Trade survey included 900 active voting investors who manage at least $10,000 in an online brokerage account.

S&P 500 has quadrupled

Of course, calling the demise of the bull market has been a bad bet in the past.

Despite the recent uptick in volatility, the S&P 500 has quadrupled since the bear market low in March 2009. The bull has survived countless scares, including the 2011 European debt crisis and debt ceiling stalemate and the early 2016 growth scare. It's now the longest bull market in American history.

And the US economy is enjoying strong growth, especially relative to recent slowdowns overseas. If that continues, the bull market could live on for years.

1 in 3 say stocks have already peaked

But it's not just investors surveyed by E*Trade growing more cautious.

The Office of Financial Research, an arm of the Treasury Department, warned in its annual report issued to Congress on Thursday that "market risks remain high" and there are more risks to the macroeconomic outlook than last year.

While overall financial stability risks are moderate, the OFR report said that "stock prices are historically high."

Forty-four percent of global fund managers surveyed in November by Bank of America Merrill Lynch say economic growth will decelerate in the next 12 months, the worst outlook in a decade. And one in three investors think US stocks have already peaked, double the amount who said that in October.

Even though the US economy is cruising along -- GDP growth clocked in at 3.5% in the third quarter --growth is expected to slow due to the US-China trade war and fading help from last year's tax cuts. The IMF recently downgraded its 2019 growth forecast for the United States and China, the world's two biggest economies.

Slowdown fears have already dented the US stock market. The S&P 500 is trading about 9% lower than its record high in September.

Recession in 2020?

Few investors are bracing for an imminent recession, the likely trigger for a new bear market. Yet there is growing concern about whether the economic expansion can endure beyond next year.

Half of economists surveyed by The Wall Street Journal expect the next recession to start in 2020. Mark Zandi, chief economist of Moody's Analytics, sees the next recession coming in the summer of 2020.

Some investors are pointing to the recent downturns in crude oil as well as autos and housing as early warnings of potential trouble ahead.

E*Trade urged investors to recognize how much risk they have in their portfolios. If the recent market volatility is too painful to stomach, investors can pare their exposure to stocks.

"We're always preparing for the Russian winter, and that holds more today than it ever would," Loewengart said.