- Both the S&P 500 and Nasdaq hit new highs on Thursday.
- Kenny Polcari expects profit-taking after the three-day weekend because it "doesn't feel like there's enough guts" to the market rally.
- Robert Fross pointed out that investors continue to shake off tweets, investigations and Trump's personality and instead look at fundamentals.
When people return to their desks after Memorial Day weekend and realize where some stock prices are, they will probably take some profits and start reallocating, trader Kenny Polcari told NCBC on Thursday.
"It just doesn't feel solid enough up here at the moment. It doesn't feel like there's enough volume, like there's enough guts to it," the director at O'Neil Securities said in an interview with "Closing Bell."
However, that's a short-term trading view. Long-term is a different story, he said.
"As a long-term investor, I think the market is great," Polcari noted. "There's huge opportunity outside of the U.S. just because … the U.S., I think, is a little bit overvalued."
Stocks came into Thursday's session riding a five-day winning streak, wiping out losses from last week's sell-off as investors shrugged off negative news from Washington.
"Investors continue to shake off tweets, investigations and the personality of our president and they continue, I guess, to look at fundamentals," said Robert Fross, co-founder of Fross & Fross Wealth Management.
"Fundamentally, the economy continues to strengthen. It's certainly not where we would like it to be but it's certainly not weakening," he told "Closing Bell."
He also doesn't think the end is near for the bull market.
"Bull markets do not die because they are over-inflated. They die because of sickness. And this economy is not sick. You cannot, however, argue the fact that equity markets are pretty pricey," Fross said.
—CNBC's Fred Imbert contributed to this report.