Amazon passes Microsoft to become the 3rd-largest U.S. company By: MarketWatch February 14, 2018 at 16:15 PM EST Amazon has knocked Microsoft off the podium, to take over as the third-largest U.S. company by market capitalization for the first time. Read More >> Related Stocks: Alphabet-A Alphabet-C Amazon.com Apple Berkshire Hathaway JPMorgan Chase & Co Microsoft NDX