Billionaire investor Carl Icahn said a market correction is "definitely coming," and he is hedging some of his investments by shorting the S&P 500 SPX, -2.07% "I've been quite concerned for the last year or so. But we have a hell of a lot of stock in our portfolio so you sort of root for the upside," Icahn told CNBC. The S&P 500 tumbled Thursday, and was last down 1.5% at 1,940, having touched a low of 1,930. Icahn's comments just hours after he published a letter to Apple Inc., in which he pushed for more share buybacks and said the tech giant's stock should be trading at $203, or more than double its closing level from Wednesday. source