Amazon Is Now America’s Biggest Company. Its 17-Year Journey to Surpass Walmart.

On Thursday, Walmart lost its crown.

Amazon.com—a 31-year-old company—surpassed 63-year-old Walmart as the country’s largest company by annual revenue. Walmart had $713.2 billion in sales in the year through Jan. 31, compared with Amazon’s $716.9 billion for its most recent full year, a narrow difference that has been years in the making.

It marks the rapid rise of Amazon, from its beginnings as an online bookseller started in Jeff Bezos’ garage to a behemoth seeking to dominate the corporate landscape from cloud computing, artificial intelligence and entertainment to online sales. For Walmart, it highlights the reality that Amazon’s sales are growing faster than its own. Last year, Amazon’s sales grew 12.4% while Walmart clocked 4.7% growth.

As Amazon grew over decades, Walmart had to change its own business model to adapt, said Bill Simon, former Walmart U.S. CEO through 2014. In that way, Walmart was “driving the bus and now they are riding the bus,” Simon said.

Inside Walmart, leadership has prepared for years to lose the title, according to people familiar with the matter. Some have been surprised it didn’t happen faster. Top executives have reframed the company’s goals to more often focus on becoming “America’s favorite place to shop,” rather than the biggest or growing fast. At a company meeting for store leadership last week in Houston, signs promoted the idea of being the favorite.In past job listings, Walmart often touted the idea that working for the “Fortune 1” company was a perk, a reference to its place atop the Fortune 500. Most of its job listings appear to have been scrubbed of the term.

A spokeswoman for Walmart declined to comment. Amazon declined to comment on surpassing Walmart in revenue, but a spokeswoman said the company delivered at its fastest speeds in 2025 and 100 million people ordered items for same-day delivery.

Walmart has held the title as the biggest company by revenue since 2001 when it stole the accolade from Exxon Mobil. For years, the two companies had jockeyed for the bragging right until 2009 when Walmart claimed it—and every year until now.

“I’ll say the pace of change in retail is accelerating,” Walmart’s CEO John Furner told analysts Thursday. “For Walmart, the future is fast, convenient and personalized.”

Amazon has steadily grown as it funneled cash into its online business, adding new categories of goods, including high-ticket items such as luxury handbags and cars. That has helped grow sales of many of those categories faster than Walmart.

The online retail giant is also investing $4 billion to build a network of same-day delivery hubs in rural America. Last year, Amazon added same-day grocery delivery in more than 2,300 towns because it has found speedier delivery times lead to more frequent shopping by customers.

Such investments have helped Amazon build market share. As of last fall, it accounted for around 9% of total U.S. retail spending, according to data from PYMNTS Intelligence, a research firm. That’s a leap from its prepandemic share of around 6%. Walmart accounts for around 7.6% of total retail spending, said the firm, about steady with its prepandemic percentage.

Consumers have responded to Amazon’s offerings. Kevin Mathew of Houston was in the market last February for a Hyundai Elantra N, a sporty version of the four-door sedan, when he decided to give Amazon’s fledgling auto-sales program a try.

“I was done in 30 minutes, top to bottom,” said Mathew, 37 years old. “When was the last time you bought a car in less than an hour?”

Other than produce, and some specialty items, Mathew says he buys nearly everything from Amazon, to the point he is worried that he is becoming addicted to the convenience and possibly harming local businesses. When he goes to hardware stores for his new home, Mathew says he often wonders whether he could have waited a day and got it cheaper on Amazon.

Amazon and Walmart have long tried to chip away at each other’s turf.In recent years, Walmart has widened its selection of marketplace sellers and items, as well as expanded same-day delivery service to 95% of U.S. households. As the country’s largest grocer, it continues to increase its share of that category online and off.Around 72% of U.S. households reported buying groceries at Walmart over the last month, according to a December survey of 2,000 people from data-science firm Dunnhumby. That was a 6 percentage-point rise from the previous year’s survey, the highest increase since the firm started tracking the metric in 2022.

Amazon has struggled to solidify a winning grocery strategy. Earlier this year, Amazon closed dozens of physical stores aimed at expanding its grocery business. But it is still growing slowly in the category. An Amazon spokesperson said half of the items ordered by its Prime subscribers for same- or next-day delivery were groceries and everyday essentials.

While Amazon is closing some grocery stores, the company says it will build new Whole Foods Market stores. It plans to build a giant retail outlet in the Chicago area that will sell both groceries and other items such as clothing and homegoods, mimicking Walmart’s store model.

The profit models for the two big companies are different, but converging. Amazon earns much of its profit from non-retail operations such as cloud computing and advertising, while grabbing retail market share with fast shipping. Walmart gets the bulk of its sales and profits from U.S. stores, while growing online and through new businesses such as advertising and membership income.

For years, purchases made through Amazon have accounted for a larger percentage of overall U.S. retail sales than Walmart, but its revenue derived from retailing was smaller. That’s because Amazon often acts as a platform for outside parties to sell their wares, known as marketplace or third party sellers. Amazon earns a fee from those sales, which flows to their revenue. Most of Walmart’s sales come directly from its inventory.

While Amazon is now the country’s biggest company by revenue, it could be hard for it to claim the title of top retailer without including sales from its other activities, said Michael Levin, an analyst at Consumer Intelligence Research Partners. “I speculate it will be a while—if ever—before Amazon overtakes Walmart in retailing,” he said.

Write to Sarah Nassauer at Sarah.Nassauer@wsj.com and Sean McLain at sean.mclain@wsj.com