Walmart has been America’s largest retailer since 1990, when it surpassed Sears to take the top spot.

Retail historians have described Sears as the Amazon of its day, since it pioneered shopping from home long before there was an internet, distributing its “Big Book” catalog by mail to millions of rural Americans with limited access to retail stores.

But by the time of Walmart’s rise Sears was no longer a disrupter. The company had become a conglomerate, having bought an insurance company and a brokerage firm, and its retail business was built on department stores, which could not match the appeal of Walmart’s discount stores.

Now a new report is predicting that the Amazon of today will supplant Walmart to become the largest U.S. retailer by 2025.

Retail Insight, the market research arm of the e-commerce consulting firm Edge by Ascential, released a report last month forecasting that Amazon’s “gross merchandise value” sales will total $631.6 billion by 2025. Walmart’s sales are projected to reach $523.3 billion by that point, having grown at a compound annual growth rate of 3.9%, boosted by its own e-commerce offering.

The report takes an interesting approach, with its focus on gross merchandise value rather than on revenue. It looks at the value of the goods the retailers sell, rather than the revenue generated by those sales. So goods sold through Amazon’s Marketplace count, even though Amazon charges the third-party sellers in its Marketplace a commission and the rest of the revenue goes to the sellers. At the same time, the analysis looks only at Amazon’s retail sales — both online and through its brick-and-mortar stores — and not at its cloud computing or advertising businesses.

The theory here is that online retailing is where the growth is, and that Amazon’s lead and its momentum preclude other retailers, even a behemoth like Walmart, from catching up.

Edge by Ascential says that e-commerce in the United States continues its meteoric rise, with online sales expected to increase to more than $1.2 trillion by 2025, up 41% from $710.7 billion in 2020, which because of the COVID-19 pandemic was itself a big year for e-commerce. E-commerce sales grew about 30% in 2020 from $546.3 billion in 2019, according to the report, which noted that e-commerce sales were $471.3 billion in 2018.

Predicting even the near future is tricky, of course. Walmart is betting that it can leverage its brick-and-mortar assets to become consumers’ omnichannel retailer of choice by letting its customers shop wherever and however they like. Amazon seems to acknowledge that such a strategy has merit, and is expanding its own network of brick-and-mortar stores.

Amazon could also face increased regulatory scrutiny, or the kind of negative pushback that Walmart experienced in the 1990s, when it was seen as a retail Goliath destroying Main Street retailers. But Amazon’s recent first-quarter results, which included a 44% net sales increase, suggest it may still be a company that can be beaten, but it is not one that can be ignored.