Walmart is gearing up to regain ground it lost to Amazon by failing early on to realize the potential of the Internet. It has shelled out $3 billion for Amazon-like multiproduct Jet.com, and about $50 million each for online sellers of men’s and women’s clothing, and outdoor gear. The late entry into the e-commerce race reports that its online sales grew 63 percent in the latest quarter, from an admittedly low base. Walmart has the advantage of a reputation for low prices and the thousands of stores that can serve as pickup points for orders placed online, or dispatch points for orders to be delivered directly to homes.

Meanwhile Amazon has produced a bit of nervousness among the upper classes by acquiring Whole Foods for $13.7 billion. Food and drink account for about 2 percent of retail sales, and it is not a sector in which Amazon’s previous incursions have produced much by way of results—not counting the accumulation of intellectual capital and a place to test cashier-free transactions and two-hour delivery techniques. Food will be a test of the ability of Amazon’s massive logistics system to adapt to the food business, involving a product more perishable than sneakers and books.