Apple stock jumps more than 5 percent after tweet from Carl Icahn

Apple shares climbed more than 5 percent Wednesday afternoon, following tweets from billionaire Carl Icahn.

In the tweets, Ichan said his firm has a "large position" in the company. Apple shares had fallen more than 30 percent since September 2012, after investors were unsure whether the company could maintain the company's pace after Steve Jobs' passing.

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 continued, saying that he had spoken to Apple CEO Tim Cook.

Had a nice conversation with Tim Cook today. Discussed my opinion that a larger buyback should be done now. We plan to speak again shortly.

— Carl Icahn (@Carl_C_Icahn) August 13, 2013

Apple shares opened at $470.94 apiece, but by afternoon trading they were priced at $493.68 each.