- Momentum players are not driving the action, as they did in the past, the Wharton professor says.
- The stock market is "very fairly valued" at current levels, Siegel says.
- The Dow, S&P 500 and Nasdaq were riding six-session winning streaks heading into Friday and the long Memorial Day weekend.
There are "a lot of momentum players" in the stock market, but overall they're not driving the action, as they did in the 1990s before the dotcom bubble burst, Wharton School finance professor Jeremy Siegel told CNBC on Friday.
The stock market is "very fairly valued" at current soaring levels, the longtime bull said on "Fast Money Halftime Report," adding the high-flying tech sector is not in danger of overheating.
"I just looked up the P-E ratio of the tech sector on estimated 2017 earnings of the S&P 500. It's still under 20," Siegel said.
"Back in 1999, the tech sector of the S&P 500 had a P-E ratio of 90," Siegel pointed out. "Are we in danger of overheating? There's always that danger. But are we in a danger zone yet? I don't think so."
But with the momentum in the market, some stocks are subject to declines when the pendulum swings the other way, Siegel said.
Over the past six trading sessions, the Dow Jones industrial average, S&P, and Nasdaq closed higher each day. The S&P and Nasdaq logged records on Thursday, and the Dow finished within 32 points of an all-time high heading into Friday's session and the long Memorial Day weekend.
As for the overall market, "the dollar being down is very positive" and so is the 10-year Treasury yield of about 2.25 percent, Siegel said.
"Stocks are still the place to be for investors," he said, predicting gains of about 7 percent annually. The S&P was up about 7.8 percent for 2017 as of Thursday's close.
Siegel also said, "U.S. citizens are underinvested abroad."
"We economists have talked about it. It's called the home equity basis," he said. "People just feel uncomfortable investing abroad. By the way, that's true around the world."