About a decade ago, when Steve Ballmer took over as CEO of Microsoft and Steve Jobs had recently reclaimed the helm at Apple, the latter had a market capitalization of 'only' $16 billion compared to Microsoft's $556 billion. Following its peak in December 1999, Microsoft's stock price has significantly declined before settling into tread-water mode. Apple on the other hand has been growing rapidly after a string of successful launches that started with the iMac, then the industry-revolutionizing iPod, and most recently the iPhone and iPad.
Shares of Apple on the Nasdaq stock exchange are, just this second, valued at $226 billion and climbing while Microsoft now stands at around $222 billion. Market capitalization is a popular metric for assessing the size of a company and its worth. The figure is derived by multiplying the number of outstanding shares of the company's stock by the share price. In the case of Apple, that's slightly over 900 million shares at nearly $250 each.