Microsoft was founded in 1975 by Bill Gates and Paul Allen and later became a leading mega-cap technology firm.
Gates and Allen established Microsoft on April 4, 1975, after developing a version of the BASIC programming language for the Altair 8800 microcomputer. The company's early success came from licensing software rather than manufacturing computers. Its MS-DOS operating system became central to the IBM PC ecosystem during the 1980s.
Microsoft expanded dramatically with Windows, Office, server software, gaming, and enterprise services. In the 2010s, its cloud-computing platform, Azure, became a major growth engine. Revenue from recurring software subscriptions and cloud services helped investors value Microsoft among the world's largest public companies by market capitalization.
Microsoft is sometimes confused with the company that manufactured the IBM PC. IBM built the computer, while Microsoft supplied the operating system. The distinction is important because Microsoft's licensing model allowed its software to appear on computers made by many manufacturers.