Walmart passes Apple to become No. 3 online retailer in U.S. Walmart has overtaken Apple to become the No. 3 online retailer in the U.S., according to a report this week from eMarketer. While Amazon still leads by a wide margin, accounting for 48 percent of e-commerce sales in 2018, Walmart – including also Sam’s Club and Jet.com – is poised to capture 4 percent of all online retail spending in the U.S. by year-end, totaling $20.91 billion.