2017 was another year of double-digit gains for the stock market. The S&P 500 is on track to clock a gain of more than 20%, which would be its best year since 2013.

Top strategists expect the bull market to continue in 2018, albeit a little more muted.

"I think we're absolutely going to expect a more muted return environment," said Kristi Mitchem, CEO of Wells Fargo Asset Management in an interview with TheStreet. "So if we think about 2018 - we're actually projecting returns of about 5-10% depending upon which market that we're looking at."

Wells Fargo (WFC) - Get Wells Fargo & Company Report Investment Institute has a 2,700 price target on the S&P 500, while JPMorgan Chase (JPM) - Get JPMorgan Chase & Co. (JPM) Report and Bank of America (BAC) - Get Bank of America Corp Report Merrill Lynch have a 3,000 target.

One theme that has dominated the markets in 2018 was how foreign stocks outperformed U.S. stocks.

The MSCI Emerging Markets ETF (EEM) - Get iShares MSCI Emerging Markets ETF Report is up over 31% this year, compared to the S&P 500's 20% increase.

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The outperformance of foreign stocks should continue in 2018, according to billionaire Ken Fisher, chairman of Fisher Investments.

"We're also in that period where foreign has overtaken from U.S. - which happened all this year - and should continue for another year or so and maybe for the rest of this bull market," Fisher said.

One wild card for the markets in 2018 is the Federal Reserve. Jerome Powell is set to succeed Janet Yellen as Chair in February. The central bank is also in the process of unwinding its multi-trillion dollar balance sheet. It's something the Fed has never done before, which could have implications for the stock market, according to Danielle DiMartino Booth, author of Fed Up.

"We had a record run rate in quantitative easing - $2 trillion poured into these markets," Booth said. "There's no head scratching about why markets are at record levels. We had record quantitative easing in [2017]."

If the Fed and the European Central Bank stick to their plans of winding down stimulus, total QE entering the markets is expected to drop to only $1 trillion in 2018, according to Booth.

2018 is likely to be a good year for the stock market, but unlike 2017, you may actually have to buckle your seat belt.

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