Icahn: I'm 'more and more' concerned about the stock market

Billionaire Carl Icahn: A lot of companies are 'way overvalued'

Billionaire investor Carl Icahn told CNBC on Monday he is "more and more" concerned about the stock market, and many companies are "way overvalued," considering the risk in emerging markets.

In an interview with Scott Wapner on "Fast Money Halftime Report," the chairman of Icahn Enterprises said he is cautious about the market on the long term basis, but on the short-term it's "anybody's guess."

Icahn did say, however, that nutritional supplement-company Herbalife is "undervalued" and is a good model that gives jobs to many people. Icahn's firm is the largest shareholder of Herbalife, and he has been in a high profile battle against hedge fund billionaire Bill Ackman over the company.

In previous comments about the market, Icahn has said the Federal Reserve has created a "false market," by not raising interest rates.

In the interview, Icahn reaffirmed his comments and said interest rates have to rise. He said in this market environment a person has to be a smart investor.

"You have some companies where there are unique qualities that aren't apparent ... that are in front of you and you buy," he said. "But sometimes that takes years and years and years."