Microsoft Corporation is a multinational technology company based in Redmond, Washington, that makes computer software, consumer devices, computers, and related services. The Microsoft Windows operating system, the Microsoft Office suite, and the Internet Explorer and Edge web browsers are among the company's most well-known software products. The Xbox video game consoles and the Microsoft Surface range of touchscreen personal computers are the company's major hardware offerings. Microsoft was rated No. 21 on the Fortune 500 list of the largest US firms by total revenue in 2020; as of 2016, it was the world's largest software maker by revenue. Along with Amazon, Google (Alphabet), Apple, and Facebook Meta), it is considered one of the Big Five businesses in the United States' information technology industry. On April 4, 1975, Bill Gates and Paul Allen created Microsoft (a portmanteau of "microcomputer software" to develop and market BASIC interpreters for the Altair 8800. With MS-DOS in the mid-1980s, it dominated the personal computer operating system industry, followed by Microsoft Windows. Microsoft employees became billionaires and millionaires as a result of the company's initial public offering (IPO) in 1986 and subsequent growth in share price. Since the 1990s, it has expanded from the operating system market and undertaken a series of corporate acquisitions, the largest of which was the $26.2 billion acquisition of LinkedIn in December 2016, followed by the $8.5 billion acquisition of Skype Technologies in May 2011. Microsoft owns the following companies or brands: Visio, Navision, Rare, Tellme Networks, aQuantive, Fast Search & Transfer, Skype, Yammer, Nokia, Zune, Hotmail, OneDrive, Bing.