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.
The worth, known as market capitalisation, is calculated by multiplying the number of shares in a company by the current share price.
Although Apple shares closed down 0.4%, Microsoft fell by 4%.
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 stylish iPod in 2001.
Its compatability with existing - but not mass-selling - Apple computers lead customers to engage with them, just as Microsoft's products looked set for long-term dominance.
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% of the world's personal computers, has not been able to match growth rates from its hey-day of the 1990s, although its last sales figures were still higher than Apple's.
This week sees the launch in Britain 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.
http://news.bbc.co.uk/1/hi/business/10168684.stm
