Warren Buffett and Carl Icahn are Cashing-In on Surprising Stocks

Billionaire investors don't always make their money from top stocks like Apple and Google -- some of their best-performing holdings might surprise you. Carl Icahn's investment in American Railcar Industries has been a bright spot in his portfolio this year -- registering double-digit gains year-to-date. George Soros upped his stake in under-the-radar biotech company Illumina to an eventual 195,000 shares in the second quarter, before reducing his position to 75,000 shares in the third quarter. With shares of Illumina up in high double-digits year-to-date, Soros likely made a pretty profit. Plus, Berkshire Hathaway's Warren Buffett added Express Scripts to his portfolio in the third quarter, which reached a new all-time high in late November and continued to climb.