When tweets move markets: Icahn and Apple

Tim Cook and Carl Icahn
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Tim Cook and Carl Icahn

Billionaire investor Carl Icahn revealed on Twitter on Tuesday that he's taken a "large position" in Apple.

"We believe the company to be extremely undervalued," Icahn said—a tweet that instantly moved the market.

In the modern era of social media, a brief comment—offhand or not—has the power to make or lose millions of people billions of dollars in an instant.

Read on for more reactions to Icahn's tweets: