Microsoft created the Windows operating system and became one of the world's first $3 trillion public companies.
Microsoft was founded by Bill Gates and Paul Allen in 1975. Its Windows operating system became a dominant platform for personal computers, while products such as Office, Azure, Xbox, and LinkedIn broadened the company's business beyond desktop software.
Microsoft's market capitalization briefly reached $3 trillion in January 2024. Market capitalization reflects the market price of a company's shares multiplied by its outstanding shares, so the ranking can change whenever share prices move. The $3 trillion milestone therefore describes a market value, not cash held by Microsoft.
IBM and Oracle are also major enterprise-technology companies, but neither created Windows. Microsoft initially developed software for the Altair 8800, and its later agreement to provide MS-DOS helped establish its position in the personal-computer industry.