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:
