Apple has pushed past arch-rival Microsoft to become the world's biggest technology company.
Changes in the share price values of the two in Wednesday's choppy trading left the total value of Apple at $222bn (£154bn).
Microsoft is now valued by investors at $219bn.
However, Microsoft still enjoys higher profits than Apple. Its most recent annual net profit was $14.6bn (£10bn), compared with $5.7bn for Apple.
Microsoft also reported bigger full-year revenues of $58.4bn, with Apple on $36.5bn.
The value of a listed company, known as market capitalisation, is calculated by multiplying the number of shares in a company by the current share price.
Apple's shares closed Wednesday trading down 0.4 per cent, while Microsoft fell by 4 per cent.
Apple, which makes computers, iPods, iPhones and now iPads, almost went out of business in the 1990s.
Its growth is partly owing to the launch of the iPod in 2001.
Although the iPod also works with computers running Microsoft's Windows operating systems, it encouraged more people to to buy one of Apple's computers.
Apple has to look back to late 1989 to see the last time it was ahead of Microsoft.
Microsoft, whose operating system runs on more than 90 per cent of the world's personal computers, has not been able to match growth rates from its hey-day of the 1990s.
This week sees the launch in the UK and eight other countries of Apple's iPad tablet computer.
Next month will see the unveiling of the next generation of the iPhone, something that has brought internet access on the move to the mass market, and led to an explosion in downloadable mobile "apps" - applications that enable a huge range of activities, from map reading to booking restaurants.
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