Apple - the world's most valuable firm - is now the most valuable company of all time, with a market value of approximately $623bn (£397bn).
The consumer gadget and computer maker has now surpassed Microsoft's record of $620.58bn set in 1999. However that figure is not adjusted for inflation.
The news comes ahead of the anticipated launch of the iPhone 5, and possibly a smaller and cheaper iPad.
Apple shares hit $664.74 in New York midday trading, and closed at $665.15.
That was $17, or 2.6%, higher than Friday's close.
There is also speculation that Apple plans to make a TV set.