Market capitalization (market cap) is a measurement of the size of a business enterprise or corporation that is equal to its share price times the number of shares outstanding (shares that have been authorized, issued, and purchased by investors) of a publicly traded company.

As owning stock represents ownership of the company, including all its equity, capitalization could represent the public opinion of a company's net worth and is a determining factor in stock valuation. Likewise, the capitalization of stock markets or economic regions may be compared to other economic indicators.

Market capitalization is calculated by multiplying a company's shares outstanding by the current market price of one share and the investment community uses this figure to determine a company's size, as opposed to sales or total asset figures.

Start the slideshow to view a gallery of the top 10 largest U.S. companies by market capitalization, as of April 7, 2011:

Google inc Iphone Ibm General electric