<P> Market capitalization is used by the investment community in ranking the size of companies, as opposed to sales or total asset figures . It is also used in ranking the relative size of stock exchanges, being a measure of the sum of the market capitalizations of all companies listed on each stock exchange . (See List of stock exchanges .) In performing such rankings, the market capitalizations are calculated at some significant date, such as 30 June or 31 December . </P> <P> The total capitalization of stock markets or economic regions may be compared with other economic indicators . The total market capitalization of all publicly traded companies in the world was US $51.2 trillion in January 2007 and rose as high as US $57.5 trillion in May 2008 before dropping below US $50 trillion in August 2008 and slightly above US $40 trillion in September 2008 . In 2014 and 2015, global market capitalization was US $68 trillion and US $67 trillion, respectively . </P> <P> Market cap is given by the formula M C = N × P (\ textstyle MC = N \ times P), where MC is the market capitalization, N is the number of shares outstanding, and P is the closing price per share . </P> <P> For example, if some company has 4 million shares outstanding and the closing price per share is $20, its market cap is then $80 million . If the closing price per share rises to $21, the market cap becomes $84 million . If it drops to $19 per share, the market cap falls to $76 million . This is in contrast to mercantile pricing where purchase price, average price and sale price may differ due to transaction costs . </P>

What determines the market share of a company
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