Carl Icahn claims Apple 'extremely undervalued'

The famous billionaire Carl Icahn has posted a couple of tweets, where he claims that Apple is  'extremely undervalued' and he is planning to obtain a bigger share of Apple.

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

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.

The result of Icahn's tweets was Apple's stock upsurging by 5%.