With the Dow Jones industrial average about 200 points away from the 20,000 level early Monday, longtime stock bull Jeremy Siegel told CNBC the market has been reacting to the prospect of a "pro-business president" in Donald Trump.
The Dow on Friday saw its 14th record closing high since the election for a gain of nearly 7.8 percent over the period. The Dow has risen nearly 13.5 percent this year.
"This is 98 percent a Trump rally," Siegel said on "Squawk Box" Monday, adding Dow 20,000 looks like it could happen this week. "We're 1 percent away. Wow, we could do that in a day."
While warning the next 1,000 Dow points are going to harder to come by than the last 1,000, he said: "The bullish trends are still in place, definitely."
"We are at a rich multiple on earnings," Siegel acknowledged. "So we got to have those earnings come in, I think, for it to move for the next 1,000."
He had been predicting Dow 19,000 by year-end, a level breached for the first time ever late last month.
The Wharton finance professor said there's a "strong likelihood" the Trump administration will be able to push through "substantial corporate tax reform" and roll back regulations, two pillars long-sought after in the business and investing communities.
"Think of how much money corporations just spend trying to move their money from one place around the world to another," Siegel said. "If we can rationalize that totally crazy system, that's a big gain in efficiency. We know we're going to bring a lot of money back from abroad."
Siegel also said U.S. businesses have been "overburdened by regulations" during the presidency of Barack Obama, and Trump's desire to deregulate is a "real strong positive."