Apple is now the most valuable stock of all time

Shares in Apple rose above $660 yesterday, making the US phone and computer giant the most valuable company of all time.

At $664 a piece in intraday trading, Apple's market value hit $622.5bn (£396.5bn), passing the previous $621bn record set by rival computer maker Microsoft at the end of 1999.

Yet analysts yesterday said the technology company was still undervalued, with Bernstein's Toni Sacconaghi putting a target of $750 on the stock.

Other analysts this year have suggested Apple will be the first company to pass $1trillion in value, which would require the shares to pass $1072. It is already worth $200bn more than its closest listed rival, oil giant Exxon Mobil.

Apple shares have gained more than 60 per cent this year, amid speculation about new Apple TVs and iPad tablet computers.