The Maze: Walmart moved far more of its U.S. business online without an obvious surge in its overall operating margin. That can look like a disappointing payoff from retail media, the ads retailers sell around shopping. But the channel mix changed underneath the headline result. Ecommerce rose from 7.7% of Walmart's U.S. retail sales in 2019 to 22.5% in 2025 in EMARKETER's estimates. A business can protect profitability while rebuilding itself. The absence of a bigger margin does not establish the absence of value.
Walmart's online shift was much larger than retail's. Total U.S. retail moved from 10.8% ecommerce penetration to 16.8% over the same period. Walmart added 14.8 percentage points, against 6.0 for the market. Its gain was roughly 2.5 times as large. These are shares of each business's own sales, not Walmart's share of all U.S. online spending. The starting point matters: Walmart began below the national online mix and finished 5.7 points above it. Treating both businesses as if they faced the same channel transition misses the size of that operational change.
The crossover came before the profitability threshold. The annual paths put Walmart below total retail in 2022 and above it in 2023, with the gap widening thereafter. Intermediate positions are approximate; the endpoint percentages are printed estimates. Yet the sequence is clear. Walmart became more exposed to online economics before its U.S. ecommerce business reached its first profitable quarter in Q1 fiscal 2026, which falls in calendar 2025. A larger online mix was therefore not automatically a larger profit pool throughout this period. More sales can bring more picking, packing and delivery work before they bring better returns.
A stable margin can hide a large internal repair job. Sarah Marzano's analysis uses Walmart's relatively steady operating margin to ask what retail media is actually for. One plausible role is absorbing pressure while the retailer changes its sales mix. That is a strategic interpretation, not a measured subsidy. The visible evidence contains no operating-margin series and no breakdown connecting advertising profit to ecommerce losses. It cannot tell us what Walmart's margin would have been without ads. Calling retail media ineffective because the headline margin barely moves would require that missing counterfactual; calling it the sole rescuer would require one too.
The useful scorecard connects ad profit to retail economics. Walmart's earnings commentary describes several profitability drivers, including delivery density, lower delivery costs, customer fees and advertising mix. Advertising sells access to shopping demand; the retail operation creates that demand and bears the cost of serving it. A management scorecard should therefore track ecommerce contribution after fulfillment alongside media contribution, rather than reward ad revenue in isolation. This is our recommended test, not a disclosed Walmart reporting framework. If ads grow while retail service deteriorates, a successful media business may still leave a weaker retailer behind.
Why it matters: Retail media teams need a clearer question than whether the retailer's margin expanded. Did their contribution help the business serve more customers, absorb a difficult channel transition or improve the economics of an order? Walmart's mix shift makes those questions tangible. It does not answer the attribution problem. The discriminating watchpoint is whether order economics improve as media income grows; otherwise, margin protection can become a comfortable name for an unresolved delivery bill.
Sources: Sarah Marzano / EMARKETER exhibit; Walmart Q1 FY2026 earnings call; Walmart earnings release.
Images: Cover AI-generated
