Mark Cuban, who made billions of dollars during the dot-com boom, said Wednesday that the stock market is not reminiscent of 1999.

"Interest rates were a lot different back then," Cuban said on CNBC's "Fast Money Halftime Report." "And you saw a lot more people participating in the market. ... You don't see that now. That individual day trading really led the market to be frothy."

The levels of day trading have receded and given way to the rise of index funds, creating a fundamentally different landscape, Cuban said.

"There's so much money chasing index funds, so as long as those funds keep on growing the market is going to go up," said Cuban, who sold Broadcast.com to Yahoo in April 1999 for $5.7 billion.

Cuban's comments Wednesday were in response to concerns from investors who are comparing the stock market's current valuation to the bull market in 1999 that concluded with collapse of the dot-com bubble.

Highly speculative internet stocks helped propel the tech-dominated Nasdaq up more than 500% from 1995 until the bubble burst in March 2000.