Apple has been named as the most valuable public company of all time after its market cap hit dizzy new heights.

The price of the iPhone firm's stock multiplied by its outstanding shares exceeded a whopping $623 billion (£397bn), eclipsing the record set by Microsoft at the peak of the dot-com bubble.

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S&P's senior index analyst Howard Silverblatt attributed the figures to the hype surrounding Apple's next iPhone, its rumoured iPad Mini, and potential entry into the television market.

At the start of trading today (August 20), Apple's shares were valued at $664.74 each. As recently as 2004, Apple was valued at $10bn, a figure which rose to $100bn in 2009.

Sales of the company's iPhone, iPad, iPod and Mac devices are on course to rank it as the world's largest technology company in terms of sales by the end of the year, CNN reports.

However, Microsoft still holds the record as most valuable company on the stock market with inflation taken into account. In 2012 dollars, Microsoft's all-time high would be $851bn, a figure that Apple shares would need to exceed $908 to topple.