Wharton Finance Professor: Stock Market Rally Isn't Over

Jeremy Siegel, a notable finance professor at the University of Pennsylvania's Wharton School, has built a solid reputation of forecasting the stock market's direction.

The professor appeared on CNBC back in July and boldly predicted that the Dow Jones Industrial Average would hit the 20,000 milestone this year.

On Tuesday, Siegel was a guest on CNBC at a time when the Dow is within 20 points of hitting the 20,000 mark, although he downplayed the significance of the index.

Siegel stated that the index itself has "no concrete meaning" since it is calculated by dividing the sum of the prices of all 30 stocks in the index by a divider number, which is currently 0.146.

It's Not Over 'Til It's Over

Nevertheless, Siegel believes the rally in the stock market will continue — but not to the same degree as when it smashed through the 10,000 mark in 1999 and rose another 12 percent.

Siegel continued that the peak of a stock market rally typically occurs when retail investors crowd into the stock market and there are no signs of this currently taking place.

On the other hand, President-elect Donald Trump's corporate tax cut proposal could help boost corporate earnings by 10 percent, and this fact may be something investors are discounting.