It’s going back and forth by the minute, but Apple on Wednesday officially passed Microsoft in terms of market capitalization. The move puts Apple in second place behind only Exxon, who holds the top spot. Exxon’s market cap is $282.02 billion, Apple’s is $228.56 billion and Microsoft is $228.12 billion.

Wikipedia describes market capitalization as:

Market capitalization/capitalisation (often market cap) is a measurement of size of a business enterprise (corporation) equal to the share price times the number of shares outstanding of a public 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.

Apple Passes Microsoft to Become Second-Largest U.S. Company by Market Capitalization [MacRumors]