20 of the Largest Ecommerce Companies in the US

US ecommerce is often treated as a synonym for Amazon, but the market is more varied. Walmart, Target and Costco have built large online businesses on top of store networks. eBay and Etsy operate marketplaces. Wayfair and Chewy are category specialists. Shopify is primarily a commerce platform rather than a retailer, but the merchants using its software account for a significant share of online transactions. The largest ecommerce companies therefore compete with different models.

That makes a single ranking difficult. Gross merchandise value, online revenue and platform payment volume are not directly comparable. This guide focuses on scale and strategic importance in US online commerce rather than forcing marketplaces, retailers and software platforms into one misleading metric.

Amazon still sets the benchmark

Amazon combines first-party retail, third-party marketplace sales, fulfilment, advertising and Prime membership. Its advantage is not simply website traffic. The company has built a national logistics network that can move products from sellers to customers at a speed few standalone retailers can match.

The marketplace model also lets Amazon expand selection without owning every item in inventory. Third-party sellers carry inventory risk while Amazon earns fees for marketplace access, fulfilment and advertising. That mixture produces economics very different from a traditional retailer.

Walmart is using stores as fulfilment infrastructure

Walmart's ecommerce growth shows how physical retail can become an online advantage. Thousands of stores put inventory close to customers, supporting pickup and same-day delivery. Target has pursued a similar model, while Costco uses its membership base to drive repeat online purchases alongside warehouse visits.

The store network reduces the need to build every fulfilment location from scratch, although picking individual online orders from stores can be operationally expensive. Retailers are investing heavily in automation to improve those economics.

Marketplaces remain important outside Amazon

eBay remains one of the largest US online marketplaces, especially in collectibles, used goods, automotive parts and specialist categories. Etsy built its position around handmade and distinctive goods, while newer marketplaces such as Whatnot have grown around live shopping and enthusiast communities.

Marketplace businesses can scale efficiently because they do not need to own most inventory. Their main challenge is maintaining trust, seller quality and enough buyer traffic to keep merchants engaged.

Specialists can win through category expertise

Chewy built a large online pet-care business by combining repeat purchases with customer service and subscriptions. Wayfair concentrates on home goods, while companies such as Carvana apply ecommerce mechanics to categories that historically required physical dealerships.

Specialists do not need to match Amazon's total scale if they can offer better selection, service or economics in one category. That is why ecommerce remains fragmented even after two decades of consolidation.

Platforms capture value without owning the customer transaction

Shopify occupies a different position. It provides software, payments and merchant services to brands that want to sell through their own websites rather than depend entirely on marketplaces. Salesforce, Adobe and other enterprise software companies serve the larger end of the commerce stack.

The future of US ecommerce is therefore not a simple contest among online stores. It is a competition among logistics networks, marketplaces, merchant software, payments, advertising and specialised retailers. The companies that control more than one layer have the strongest ability to capture economics beyond the initial sale.