This Investor's Tweets Boosted Apple's Stock More Than 5%

The largest company in the world just saw its stock moved significantly by two tweets from an investor.

Carl Icahn, a billionaire activist investor who has been in the news a lot lately for his efforts to thwart Michael Dell's efforts to take his company private, tweeted on Tuesday that he has a "large position" in Apple and believes the company's stock is "extremely undervalued."

We currently have a large position in APPLE. We believe the company to be extremely undervalued. Spoke to Tim Cook today. More to come.

— Carl Icahn (@Carl_C_Icahn) August 13, 2013

Icahn followed that up with another tweet noting that he had had a "nice conversation" with Apple CEO Tim Cook. Apple has since confirmed that the two had a conversation. Read more...