Microsoft Corporation is an American multinational technology conglomerate headquartered in Redmond, Washington. Founded in 1975, the company became influential in the rise of personal computers through software like Windows, and has since expanded to Internet services, cloud computing, artificial intelligence, video gaming, and other fields. Often described as a Big Tech company, Microsoft is the largest software company by revenue, one of the most valuable public companies, and one of the most valuable brands globally. Founded by Bill Gates and Paul Allen to market BASIC interpreters for the Altair 8800, Microsoft rose to dominate the personal computer operating system market with MS-DOS in the mid-1980s, followed by Windows. During the 41 years from 1980 to 2021 Microsoft released 9 versions of MS-DOS with a median frequency of 2 years, and 13 versions of Windows with a median frequency of 3 years. The company's 1986 initial public offering and subsequent rise in its share price created three billionaires and an estimated 12,000 millionaires among Microsoft employees. Since the 1990s, it has increasingly diversified from the operating system market. Wikipedia