Shares in technology icon Apple broke through the $500 mark for the first time yesterday.
The milestone marks the latest step in a rally that began more than two weeks ago, when the US giant reported bumper sales and profits for the festive holiday season quarter.
Apple has been trading the position as most valuable company in the world with Exxon Mobil since last summer, but the latest rally has made it about 17 per cent more valuable than the oil company.
The maker of the iPod and iPhone has been locked in an escalating patent battle with Google and handset-makers such as HTC and Samsung over their operating systems.
It has now asked a US court to block Samsung from selling its new Galaxy Nexus smartphones, which use Google’s newest version of Android, called Ice Cream Sandwich, alleging four patent violations.