And, when Icahn says he's taken a big stake in something, it moves the needle even on companies the size of Apple.
Yesterday, the 77 year-old Icahn acted like a high school kid, taking to Twitter to tell everyone about his newest love and most recent phone call. At 2:21PM, Icahn tweeted:
We currently have a large position in APPLE. We believe the company to be extremely undervalued. Spoke to Tim Cook today. More to come.
Within an hour of that tweet, Apple's value increased by $10 billion. Apple shares have finally broken back above the $500 mark and Icahn wants the company to buyback enough stock to push it above $700. His position is believed to be worth about $1 billion.
But what about the other 21 stocks Icahn's company, Icahn Associates, has in its portfolio?
Five of those companies have had enormous returns this year. They are:
Of those names, which one could be the best bet to see higher returns?
We ask Steve Cortes, founder of Veracruz TJM, to pick the company he believes has the fundamentals to drive its value even higher. Do the charts agree with Cortes? Talking Numbers contributor Richard Ross, Global Technical Strategist at Auerbach Grayson, looks at that company's technicals.
To find out which stock in Icahn's portfolio may have even more upside ahead, watch the video above.