Two companies now sit at the center of nearly every online purchase Americans make. New 2026 figures show that Amazon and Shopify together account for roughly half of all US e-commerce — Amazon with about 35.7% of online sales and Shopify powering another 14%. A few years ago that combined share sat closer to 43%. The concentration is accelerating.
It is the clearest sign yet that the online shopping market, once imagined as an open frontier for scrappy independent sellers, has consolidated around a small number of dominant platforms.
The Amazon-Walmart handover
The concentration story sits on top of an even larger milestone. Earlier this year, Amazon overtook Walmart to become the largest retailer in the United States — ending a run at the top that Walmart had held for well over a decade. Depending on the yardstick, Amazon's ascent is measured in total revenue or in gross merchandise value, but the direction is the same: the retail crown has moved from the big-box aisle to the fulfillment center.
Analysts credit the shift to a familiar trio of strengths — selection, pricing and delivery speed — reinforced by the enormous profits Amazon earns from its cloud division, which it can reinvest in logistics and low prices.
Shopify's quiet empire
If Amazon's dominance is loud, Shopify's is nearly invisible — and that is the point. Shopify does not sell to shoppers directly. It powers the storefronts of millions of independent brands, from one-person operations to household names. Every time a customer checks out on a direct-to-consumer website, there is a strong chance Shopify is running the transaction behind the scenes.
That model makes Shopify the connective tissue of the "everything else" economy — the vast market of brands that do not want to live entirely inside Amazon's ecosystem. Its 14% share represents the collective weight of countless small merchants who have chosen to own their customer relationships rather than rent them.
Why the concentration matters
For shoppers, platform concentration is a double-edged sword. The upside is convenience, reliability and competitive pricing. The downside is that when two companies control half a market, they also shape its rules — the fees sellers pay, the ad placements that determine what you see first, and the data that decides which products get recommended.
For sellers, the stakes are higher still. A brand that depends on Amazon for discovery is subject to Amazon's advertising costs and algorithm changes; a brand on Shopify owns its storefront but must find its own traffic in an increasingly expensive digital ad market. Increasingly, the winning move is to be present on both — using Amazon for reach and a Shopify store for margin and loyalty.
The AI wildcard
The next competitive front is already forming around AI. Retailers are racing to embed shopping into AI assistants, letting customers describe what they want in plain language and have the system find, compare and check out on their behalf. Walmart has been pushing AI-guided checkout across its stores and website, and social platforms are pouring billions into creator-led "shoppable" video. Whoever controls the AI layer that sits between shoppers and products could reshuffle these shares again.
The forward look
For now, the trend line is unmistakable: online retail is consolidating, not fragmenting. The independent seller's dream of a level playing field has given way to a landscape defined by two gravitational centers. The smart response for merchants is not to fight that reality but to work within it deliberately — diversifying across platforms, investing in owned channels like email and loyalty programs, and preparing for a near future in which an AI agent, not a search bar, is the first thing standing between a shopper and a sale.
