Apple has surpassed Microsoft as the largest technology company in the world by market capitalisation, shortly before the iPad went on sale around the world.
Apple's move comes as the company's iPhone, and now its iPad tablet computer, take on more of the personal computing tasks once handled by computers running Microsoft programs.
Market cap is the dollar value of a company's outstanding shares. During afternoon trading Wednesday, Apple Inc.'s shares rose to $248.47, pushing its market cap up to about $US226 billion ($A273.81 billion).
Microsoft Corp.'s stock slipped to $25.49, for market cap of about $US223 billion ($A270.17 billion).
The only US business with a higher market value is Exxon Mobile Corp. The oil company's market cap is about $US281 billion
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However, the news does come amid some bad PR for Apple, as news of a string of suicides at an iPhone assembly plant escaped from Shenzen, China.
For Australian fans of the company, there's another special milestone this week: the iPad arrives.
Australian iPad fans brave the rain
Rahul Koduri has been camped out in front of Apple's Sydney CBD store since 2am on Thursday and hopes to be the first person in Australia to get his hands on the iPad when it
goes on sale on Friday.
The 22-year-old Blacktown resident had to make arrangements with his boss at Telstra to take the day off to line up for iPad's Australian retail launch.
"I want to be the first to get it," he told AAP as he sat alone outside the George Street store on Thursday afternoon.
The Wi-Fi version of the iPad sells for $629 including GST, while the Wi-Fi version with 3G costs $799.
Mr Koduri didn't pre-order an iPad, preferring to stand in line.
"The experience of going to an Apple store and buying it - there's just no other company like that. It's like a cathedral when you're inside there."
Mr Koduri expects more buyers to brave the chilly Sydney weather, and possible showers, and queue up outside the store as the clock ticks closer to the Friday 8am launch.
"I expect more people to come after 12am tonight and into the early hours on Friday," he said.
"I've read all the forums online and (also) my friends are pretty keen on coming down tonight."
Mr Koduri so far has been offered coffee, an umbrella and permission to use the Apple store's bathrooms, if he needs to freshen up.
"It'll be cold, but I've got some blankets and jumpers with me. But in terms of rain, one of the Apple guys said if it rains too much they'll let us in."
In any case, he has his laptop to watch movies through the night.
