The Maze: U.S. online grocery is splitting into two operating models. Walmart keeps almost every order inside its own app and website. Supermarkets increasingly let marketplaces own the checkout. Brick Meets Click's first-half comparison puts Walmart's first-party share near 98% in 2Q26, while the supermarket aggregate falls to roughly 44%. That is more than a channel shift. It changes who sees the customer, controls the service and captures the economics around the basket.
The gap widened because the two groups moved in opposite directions. Walmart's first-party share rose from roughly 96% in 2Q25 to 98% in 2Q26. Supermarkets fell from about 52% to 44%. The eight-point decline moves the average supermarket below majority first-party ordering, while Walmart gets even closer to full concentration. The comparison measures share, not volume, and the bar values are approximate, but the direction is hard to miss.
Marketplace reach comes with a customer-relationship toll. When checkout moves to a third party, the supermarket may still supply the basket, but it no longer owns every signal around discovery, substitutions, service and payment. Brick Meets Click says some individual grocery banners exceed 80% third-party ordering, so the aggregate hides a wide operating range. Loyalty IDs can preserve part of the connection, but only when shoppers enter them and receive a clear benefit. The marketplace still controls much of the interface.
Walmart has turned first-party traffic into an operating system. Its walled-garden strategy feeds retail media with more owned attention, lets store teams pick and stage orders together, and creates denser batches for Spark drivers and owned delivery routes. Walmart+ and aggressive advertising help pull demand into that system. Scale matters, but the advantage compounds because customer traffic, labor productivity and last-mile economics reinforce one another.
Supermarkets need a design choice, not a blanket retreat. Third-party marketplaces can add demand and make delivery easier to launch. The problem starts when reach becomes dependency. Brick Meets Click's Three C's—connection, control and cost—offer a practical audit across ordering, assembly and distribution. A grocer does not need to copy Walmart everywhere. It does need to decide which stages must remain first-party, where loyalty bridges are essential and what margin it is willing to rent away.
Why it matters: The next grocery platform battle is not just about who fulfils the basket. It is about who owns the customer memory around it. Marketplaces can buy supermarkets reach, but first-party ordering gives retailers more data, retail-media inventory and operating leverage. Walmart has made those benefits part of one system. Supermarkets risk becoming suppliers inside somebody else's interface unless they rebuild a reason for shoppers to order direct.
Sources: Brick Meets Click LinkedIn post | Brick Meets Click | Mercatus
