Apple passes Microsoft to become world's biggest tech company worth $222bn

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. Microsoft is now valued by investors at $219bn.

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, BBC states.

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.

Apple has to look back to late 1989 to see the last time it was a bigger company than Microsoft.