Apple's stock market value closed above $500 billion on Wednesday making it the most valuable company in the world at present.

The companies to make it to the top five publicly traded American companies having the greatest market capitalization are:

1. Apple

Sales of its iPhones and iPad tablet computers helped Apple report record-breaking profits. The company's profits for the quarter ended Dec. 31 stood at $13.1 billion, 36 percent more than the average analyst forecast while revenue beat forecasts by $7.3 billion.

2. Exxon Mobil CorpExxon, the multinational oil and gas corporation, has a market value of $407 billion. It was formed in 1999 following the merger of Exxon and Mobil. The company's headquarters are located in Irving, Texas, and it markets products around the world under the brands of Exxon, Mobil and Esso.

3. Microsoft CorpMicrosoft has a market value of $266 billion. Paul Allen and Bill Gates founded the company in 1975, which then went on to dominate the home computer operating system market. It had a market value of more than $500 billion briefly at the end of 1999 and again in early 2000.

4. International Business Machines Corporation (IBM)IBM, founded in 1911, has a market value of $228 billion. IBM manufactures and sells computer hardware and software and also offers information technology consulting services.

5. Chevron CorpChevron has a market value of $216 billion. It is involved in oil, gas and geothermal energy industries. Its activities include oil and gas exploration, production, refining, marketing and transport.