Mr Ichan says he thinks the shares are worth $240 (£153), almost double the $130 they are currently trading at.

Last October, Mr Icahn argued Apple's share price was artificially low and really worth $203 apiece.

The shares have gained more than 25% since then.

"It is our belief that large institutional investors, Wall Street analysts and the news media alike continue to misunderstand Apple," Icahn wrote in the letter.

Mr Icahn says Apple is poised to "dominate" two new markets, television and cars.

This is a factor which other investors appear to ignore, he says.

Share buybacks

Mr Icahn assumes the company will post a profit of $12 per share in 2016 and thinks the company ought to be worth 18 times its earnings. He estimates each share can claim $24.44 in cash.

Mr Icahn owns about 53 million shares in Apple, or less than 1% of the firm.

He has lobbied Apple to return some of its cash to shareholders in the form of share buy-backs, where a company buys its own shares in the market, shrinking supply of the stock with a view to increasing the value of each remaining share.

Apple last month said it would ramp up its share-buying programme, returning $200bn to investors, up from $130bn.

The firm reported a $13.6bn profit for the first three months of 2015, a gain of 33%, with revenue up 27% to $58bn.

Sales in greater China leapt 71% to $16.8bn, outpacing those in the US for the first time, and helping to drive the sharp profit rise.

(BBC)