While Robertson agrees that the economy is recovering, he feels one of the biggest drivers of the recovery are bubbles in the financial markets. He says those bubbles are eventually likely to “bite us.”

“The bubble will burst in a very bad way,” says Robertson.

Robertson made the comments as part of a panel discussion at the Bloomberg Markets Most Influential Summit on Monday in New York City. During the panel discussion, Robertson said he is most concerned about the bond market. Governments have been buying bonds to boost their economies. That’s driven down interest rates. As a result, according to Robertson, savers have no place to put their money. That’s driven more people into the stocks, creating a bubble in that market as well.

Robertson didn’t quantify why he thought bonds or stocks were in a bubble, or at what point they became overpriced.

William Conway, one of the founders of private equity firm Carlyle, who was also on the panel, said that he also sees signs of a bubble, especially in the credit market. He said pressure from bank regulators doesn’t seem to have stopped banks from handing out loans. “We can get all the leverage we want, and are often offered more than we want,” says Conway. “Not sure that’s all that healthy.”

But even if prices are high, Conway said he didn’t see a “catalyst” for stocks or bonds to go down now. “The American economy is the best place to invest right now,” says Conway.

Robertson countered that bubbles always burst, and that the reason bubbles form is because it’s often hard to see why prices will go down. “The drop in 1987 came out of the blue,” says Robertson.