Next year will likely bring lower returns and perhaps a "pause" for the stock market, longtime bull Jeremy Siegel told CNBC on Monday.
In fact, he believes the market is "clearly near to a top."
"We have one more push and I think it's connected with the corporate tax reform," the Wharton School finance professor said in an interview with "Closing Bell."
While he's not warning everyone to sell everything, he sees valuations and political uncertainty slowing down the stock market in 2018.
"Clearly now at these valuations we're not going to get the double-digit returns that certainly we've gotten over the last six or seven years, on average," he said.
Siegel expects returns under 10 percent.
"What do you look forward to in 2018 that could keep this market … as buoyant as it's been this year? It's been a great run," he said. "We might have a pause."
Siegel is known for his bullish predictions. In July 2015, he said the Dow Jones industrial average could hit 20,000 by year-end. In November of that year he pushed his timeline back to 2016. The Dow broke the mark on Jan. 25, 2017.
In February, he told CNBC that Dow 22,000 was "on the horizon." The blue chip index hit that level in August.
His latest call is for Dow 24,000 by the end of 2017, but has said it is predicated on the passage of tax reform.
— CNBC's Tae Kim and Berkeley Lovelace Jr. contributed to this report.