One expert says there's one indicator that's worrying, despite continued market gains with the Nasdaq hitting its highest levels of the year on Tuesday.
"Over the very long term it's a sign of weakness. It signifies weak global growth, and it signifies geopolitical instability as well as a flight to safety," Altman said on Tuesday.
But overall, this rally isn't all that surprising, according to Altman. He said that the rally is a reflection of four things.
"One is that interest rates are going to be lower for longer. The second is that Brexit isn't going to have any meaningful effect on the U.S. The third is that the U.S. economy continues to be steady even at this 2 percent rate we've been seeing now for two or three years, and finally that other markets are flashing signs which are positive for equities," he said.