The immediate success of the iPhone 4S saw Apple's shares reach an all-time yesterday.
The tech giant yesterday revealed that it has sold 4m of the new handsets throughout its first three days on sale. That's nearly twice as many as its predecessor the iPhone 4 sold in the same period.
At one point Apple shares were trading at 426.38 before eventually closing at 419.99.
That gives the company a market cap of $389bn, up from the $341.5bn it was worth in August when it briefly overtook Exxon Mobil as the world's most valuable company.
At the start of 2011 Apple shares were worth 322.56. That means the company's value is up 32.3 per cent year-to-date.
Back in mid-1997 Apple shares were worth just 3.891.