Walmart CEO Doug McMillon keeps a photo on his phone that lists the top 10 retailers in the U.S. over the past few decades to remind him how so many companies come and go. Walmart wants to keep its No. 1 spot, which it's held since the 1990s when it overtook Sears.
"After learning from so many people ... we know that retailers come and go," McMillon told CNBC's Becky Quick Thursday, after he spoke in Washington, D.C., at the Business Roundtable CEO Innovation Summit. "Businesses grow and they don't change enough and they decline over time. Retailers do that on a bit of a faster cycle."
McMillon added Walmart has a "healthy paranoia" to stay ahead of rivals. Today, the retailer is seen as neck and neck with Amazon, which is starting to invest more in real estate and open stores while building out a bigger platform for food and apparel online. In fact, the e-commerce giant is expected to overtake Walmart as the No. 1 apparel retailer in the U.S. by the end of this year, according to Morgan Stanley.