'Super' bull Siegel: I'm rolling back my 2016 forecast — here's why

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Uncertainty is taming one of the stock market's biggest bulls — it's the reason behind Jeremy Siegel's decision to trim his year-end forecast.

"Although a number of firms have beat their third-quarter estimates, guidance has not been overenthusiastic.... We have the election to go through. You have the Fed hike to go through," said the University of Pennsylvania Wharton School finance professor on Thursday on CNBC's "Trading Nation." "It's going to be harder to make headway."

Siegel, who has had a 2,300 year-end price target on the for much of the year, now predicts the index will close between 2,250 and 2,300, just a few percentage points higher than current levels.

The activity surrounding the 10-year Treasury isn't making a case to buy stocks either. It's up more than 5 percent over the past five sessions. This as the S&P stumbles more the 1.4 percent since earnings season began earlier this month.

"You need bang-up earnings and super guidance to get over the hump of a rising 10-year.... That's the competition," said Siegel, who believes the next interest rate hike will happen in December. "People are coming to the conclusion, 'Yeah, the Fed is going to hike,' and then the question is, 'How much are they going to hike in 2017.' That's the anxiety that's putting pressure on these stock prices."

Siegel stresses that the stock market is still the best place for investors to be, and he's by no means a 'bear' right now.

"The Fed is raising [rates] because they think the economy is sounder and we're going to get faster growth," argued Siegel. "I think we're going to get an over 3 percent GDP reading for the third quarter, which would be the biggest quarterly rise in two years."

Even though it's a strong economy, which ultimately drives stocks higher, Siegel cautions stocks will flutter a little bit and get nervous as the yields rise.

"You know, we could have a nice year-end rally that could bring us to my original prediction rather than to the range — I hope we do," Siegel said. "But, these challenges are going to be facing the market and they're going to keep it pretty range-bound I think over the next few weeks."

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