Costco sticks with its warehouse membership shopping club model, although that has developed from a supermarket-style chain to offering everything from a full travel service to designer clothing and a hearing aid clinic. Amazon (NASDAQ: AMZN) and Costco Wholesale (NASDAQ: COST) are two powerhouse stocks that, along with Walmart, dominate U.S. retail shopping. Both Costco and Amazon experienced elevated sales growth at the beginning of the coronavirus pandemic, and they're both seeing slowdowns in the current inflationary environment.