Fortune 500 Rank: No. 49
Revenue: $61.1 billion
Top Executive: CEO Jeff Bezos
Just an Internet bookseller when founded 19 years ago, Seattle, Wash.-based Amazon.com is now the 800-pound gorilla of online retailers. This year it cracked the top 50 of the largest U.S. companies as it moved up from No. 56 in 2012.
Amazon has become more than just a major applier of the Internet and cloud technology. It's become an influential player there as well with its Amazon Web Services division that provides cloud services for businesses and consumers.