The Maze: U.S. online grocery has spent five years changing landlords. Walmart moved from the high-20% range in 2Q21 to the high-30s by 2Q26, while supermarkets fell from the mid-30s to the low-20s. The crossover came in late 2022; the gap kept widening. This is not a tidy one-for-one transfer, and the quarterly values are not published. But the direction is clear: the digital grocery aisle now rewards a mass retailer that can combine low prices, local inventory, delivery speed and one customer account.
The decisive break came after Walmart passed supermarkets in late 2022. The exact five-year comparison shows two different trajectories. Walmart climbs, then holds near the upper-30% band. Supermarkets decline, briefly stabilize, and drop again into 2026. Brick Meets Click separates competitive factors from market factors but does not disclose the marker key. That is a useful constraint: price pressure and retailer execution both matter, but the evidence does not assign a causal percentage to either.
Walmart is gaining inside the only part of grocery that is really growing. U.S. eGrocery sales rose 21.5% year over year in July 2026, driven mainly by a 14.9% increase in order frequency. Delivery produced 60% of that growth while physical-store sales fell 2.6%. The share contest is therefore more valuable than it first appears. Walmart is not just taking a larger slice of online grocery; it is gaining exposure to the channel supplying the category's incremental demand.
Its store network has become a local fulfillment system. Walmart says it completed millions of sub-30-minute deliveries to more than 19,000 U.S. ZIP codes in the first quarter of 2026, and 26% of Express deliveries were already arriving within half an hour. The company uses store proximity, basket size, driver availability and distance to decide where that promise works. This turns a legacy physical footprint into a speed advantage: stores hold grocery inventory close to households, while one app can sell pickup, scheduled delivery, one-hour service and immediate fill-in trips.
Owning the checkout makes the operational flywheel stronger. Brick Meets Click describes Walmart's first-party model as a deliberate walled garden. More direct orders create retail-media signals, let store teams batch picking and staging, and improve route density for Spark drivers. Walmart+ can convert delivery value into repeat behavior. Supermarkets often need third-party marketplaces for reach, but that reach can fragment data, customer experience and economics. Fresh produce remains the vulnerability: speed wins the order only if execution earns trust when the basket arrives.
Why it matters: Grocery used to favor local density by default. Digital grocery favors the operator that can turn density into a coordinated system. Walmart joined value pricing, stores, membership, first-party data and fast delivery before many supermarkets solved any one of them at scale. Regional grocers do not need to copy Walmart's footprint. They do need a sharper answer on where they can still win—fresh quality, local assortment, loyalty and reliable service—and where a marketplace relationship quietly turns them into inventory behind somebody else's interface.
