"If there were no way to short stocks, the probability of stock market bubbles would be much greater," said hedge fund manager Bill Ackman of Pershing Square.  

"There is tremendous amounts of money sitting on the sidelines. There is enormous M&A activity. The greatest thinkers in the corporate world are saying that it is cheaper to buy than to build. This says to me that the stock market still has value in it. We're a long way from expensive," said Milton Ezrati,

"Whenever I hear someone in finance say that a one in two-billion-year event just happened, I say that you just demonstrated you have a model for measuring tail risk that isn't any good," said former Treasury Secretary and Harvard University President Larry Summers.

"Everybody talks about the Volatility Index (VIX), but the new fear gauge is the 10-year Treasury bond," said Art Cashin of UBS Financial Services.