Microsoft, among the world's largest companies by market capitalization, owns the Windows operating system.
Microsoft developed Windows as a graphical operating-system family for personal computers. The first retail version, Windows 1.0, was released in 1985, building on the company's earlier MS-DOS business.
Bill Gates and Paul Allen founded Microsoft in 1975. The company later expanded into productivity software, cloud computing, gaming, search, business software, and hardware such as Surface devices and Xbox consoles.
Windows is not the same thing as Microsoft’s entire business. Azure cloud services, Microsoft 365, enterprise software, and gaming are also major activities. A company's market cap reflects the market value of its outstanding shares, not the value of Windows alone.