Watch out, retailers. This is just how big Amazon is becoming By: CNBC.com News July 13, 2018 at 11:24 AM EDT The company is expected to take almost 50 percent of the U.S. e-commerce market by year's end. Read More >> Related Stocks: Amazon.com Apple Best Buy Costco Wholesale Home Depot Macy's Wal-Mart Stores, Inc. Wayfair Inc eBay