According to Business Insider, Amazon’s Project Mercury aims to open more than 1,000 same-day fulfillment centers by 2031, putting 80% of Prime customers within 10 miles of one. That goes straight at one of Walmart’s biggest advantages in grocery and everyday essentials. About 90% of the US population lives within 10 miles of a Walmart or Sam’s Club, and Walmart uses that store network to offer fast delivery. As Amazon closes the distance, what happens to Walmart’s business?
We don’t have to wait until 2031 to find out. Amazon has already been adding same-day capacity, and Consumer Edge transaction data lets us measure what happened in those markets. In December 2025, Amazon expanded same-day fresh grocery delivery to more than 2,300 cities and towns, including Boise, Salt Lake City, Omaha and Des Moines. Around the same time, it opened new same-day fulfillment centers serving Rochester, Pittsburgh and Jacksonville. Once same-day delivery arrived or expanded, Amazon (ex marketplace) customers started ordering more often. In markets with a new fulfillment center, the average shopper went from 1.6 to 1.9 orders a week, an 18% increase. Markets that gained same-day grocery rose 11%. In markets without a same-day center, order frequency didn’t move at all.
We compared shopping frequency in these metro areas in the first half of 2026 with the first half of 2025. We then benchmarked them against 10 metro areas without an Amazon same-day fulfillment center. Given that third party sales are fulfilled from a mix of Amazon and non-Amazon facilities, they were excluded. The increases show up most clearly among Amazon’s heaviest shoppers. In markets with a new fulfillment center, the share of shoppers ordering three or more times a week rose from 13% to 19%. In the grocery markets it went from 18% to 22%. In markets without same-day centers, it stayed at 17%.
While the new centers are a clear win for Amazon, they don’t appear to be pulling Walmart’s existing customers out of its stores. In every group of markets we studied, Walmart shoppers made about 1.5 store visits a week in both periods.
Over the next five years, Consumer Edge transaction data can keep measuring Project Mercury’s impact as it rolls out market by market. This includes whether Amazon’s gains in frequency start to come at Walmart’s expense, how basket sizes change as shoppers order more often, and how Walmart’s own delivery business responds.
How business leaders use this data
- Retail strategy teams track how a competitor’s new fulfillment capacity changes shopping frequency, market by market, instead of waiting for quarterly results.
- Store and real estate teams benchmark their own in-store visit trends against control markets to see whether a rival’s expansion is pulling traffic.
- Insights analysts monitor their heaviest shoppers to measure where loyalty is growing or slipping as delivery options change.
Methodology: Consumer Edge card transaction data, January to June 2025 vs. January to June 2026 (through June 21, before Prime Day). Orders per shopper per week is the average number of Amazon.com (first-party) transactions in a week among people who made at least one purchase that week. Walmart store visits are in-store Walmart transactions, excluding fuel, measured the same way. Group figures are simple averages across metro areas (CBSAs), based on cardholder location.
New same-day fulfillment center: Rochester, NY; Pittsburgh, PA; Jacksonville, FL.
Same-day grocery added (December 2025): Boise, ID; Des Moines, IA; Fort Collins, CO; Omaha, NE; Salt Lake City, UT.
No same-day fulfillment center: Lexington, KY; Tulsa, OK; Syracuse, NY; Little Rock, AR; Fayetteville, AR; Anchorage, AK; Billings, MT; Charleston, WV; Chattanooga, TN; Shreveport, LA.
