This stock chart shows the power of Twitter. Or perhaps just the power of a billionaire on Twitter.
At 2:21 p.m. ET, legendary investor Carl Icahn Tweeted that he has a huge stake in Apple and then the stock ripped.
The 77-year-old investor added more than $17.26 billion to Apple's market cap this afternoon.
The stock was last trading around $494 a share with 908.5 million shares outstanding. The stock was trading around $475 pre-Tweet.
Check out the chart:
