Same-Day Delivery Just Became the Floor. Walmart Already Knew.

FedEx announced this week that it is re-entering the same-day delivery market through a partnership with OneRail, a last-mile software company. The service gives retailers a definite end-of-day delivery option, according to Jason Brenner, FedEx’s senior vice president of digital. OneRail covers nearly 99% of the U.S. through a network of more than 1,000 carriers and 12 million delivery drivers, currently handling 80,000 deliveries of 30 minutes or less per day. The announcement came one week after Amazon rolled out one-to-three-hour delivery windows in thousands of U.S. cities.

FedEx largely exited the same-day market in 2023, except for select items like temperature-controlled pharmaceuticals, according to Bruce Chan, a senior equity analyst at Stifel. The new partnership with OneRail allows FedEx to offer the service again without using its own trucks and employees, reducing the operational risk of a broad same-day commitment.

The more instructive development for Walmart suppliers is not what FedEx announced. It is what Walmart’s own fulfillment data already shows about where the speed gap lives inside the Marketplace seller population.

Walmart’s Store Network Already Set the Speed Standard FedEx Is Now Chasing

Walmart reached 93% of U.S. households with same-day delivery as of its Q4 fiscal 2025 earnings release in February 2025, up from more than 80% of the U.S. population in October 2023. The mechanism is Walmart’s store network, not a carrier partnership. The company was closing in on covering 95% of the U.S. population with delivery in three hours or less as of mid-2025, with the number of deliveries completed in under three hours growing 91% in the first quarter of fiscal 2026 for Walmart U.S.

Walmart’s U.S. store-fulfilled delivery sales jumped nearly 50% in the quarter ended August 2025. About one-third of deliveries from stores arrived in three hours or less, with 20% of that portion arriving within 30 minutes, according to CFO and EVP John David Rainey on an earnings call.

FedEx SameDay Local is a response to the speed environment Walmart helped create. For 1P suppliers, this is largely background news. Their products move through Walmart’s own fulfillment infrastructure, and Walmart owns the last-mile relationship. The question of which carrier delivers the package is not theirs to answer.

The Exposure Is Concentrated Among 3P Sellers Managing Their Own Fulfillment

For 3P Marketplace sellers using seller-managed fulfillment, the dynamics are different. Walmart’s expedited delivery program requires sellers to deliver on or before the estimated delivery date for at least 90% of OneDay and TwoDay orders in a 30-day period, per Walmart Marketplace Learn. Maintaining those tags, and the search visibility and Buy Box advantage that come with them, depends on inventory positioned close enough to customers to make next-day and one-day promises credible.

Sellers using WFS see 50% GMV growth on average for items carrying the “Fulfilled by Walmart” tag and delivery promises of two days or less, according to Walmart’s own first-party data. That figure reflects how heavily Walmart’s algorithm rewards speed. Sellers who have migrated to WFS are largely insulated from the carrier competition FedEx SameDay Local represents, because Walmart’s network handles their last mile. Sellers who have not migrated face a different calculation.

For sellers managing their own fulfillment, FedEx SameDay Local is a credible option worth evaluating. The service connects retailers to OneRail’s carrier network through intelligent order matching, with live tracking from pickup to delivery. Retailers set their own pricing using OneRail’s rate card, giving them flexibility on whether to pass the cost to customers or absorb it. Large, oversized, and specialized items are eligible for the service, and the platform offers 24/7 monitoring to anticipate delays throughout delivery. For sellers in categories where same-day demand is high and WFS economics are not favorable, this is a viable infrastructure path that does not require building a proprietary last-mile network.

The Inventory Question Is More Urgent Than the Carrier Question

FedEx SameDay Local can only deliver what is already near the customer. That is the constraint every seller-managed fulfillment operation faces, and it is the one that carrier partnerships cannot solve on their own. A seller with inventory concentrated in one or two fulfillment locations will struggle to offer credible same-day or next-day coverage across Walmart’s customer base regardless of which carrier they use.

Walmart’s own fulfillment investment makes this concrete. In April 2025, Walmart expanded delivery to 12 million more households using geospatial technology that maps delivery zones as hexagonal grids, allowing multiple nearby stores to fulfill a single customer’s order if one location does not carry a particular item. That architecture is only possible because Walmart’s inventory is distributed across more than 4,600 stores. Sellers managing their own networks have no equivalent density.

Speed-tier eligibility on Walmart Marketplace is increasingly a function of inventory placement, not carrier selection. Sellers whose distribution footprint does not match Walmart’s customer geography will find that even a same-day capable carrier cannot close the gap. Sellers already enrolled in WFS, or who have positioned inventory with approved third-party providers like Flexport or ShipBob in major markets, are better placed to hold their speed tags as the delivery floor continues to rise.

OneRail CEO Bill Catania told CNBC that the FedEx partnership “lets retailers own their customer and their data,” which is the same logic Walmart applied when it built its own last-mile network rather than depending on traditional carriers for express delivery. For Marketplace sellers, owning that relationship starts with having inventory close enough to the customer to make the delivery window a real offer rather than a best-case scenario.

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