Amazon reportedly wants more than 1,000 same-day fulfillment centers operating in the United States by 2031, up from roughly 85 today. The September 16 report is based on internal planning documents, not a public launch announcement, but the scale is large enough that FBA sellers should pay attention now.

Business Insider’s report on the plan says the initiative is called Project Mercury. The documents describe a network designed to put a same-day facility within 10 miles of 80% of U.S. Prime members by 2031.

Amazon cautioned that the internal projections are preliminary, subject to revision and should not be treated as final plans. That qualification matters. There is no announced seller fee, enrollment program or new inventory rule attached to Mercury today.

The reported network is much more local

Amazon’s conventional fulfillment network can move a broad catalog across large regions. The reported Mercury model adds a denser layer built around popular products and short delivery distances.

The documents reviewed by Business Insider say Amazon’s same-day facilities stock about 90,000 popular products. A smaller facility design, called Orbital, would cover roughly 100,000 square feet and process about 75,000 same-day and perishable units daily. Those are internal estimates, not operating guarantees.

The projections show same-day facilities handling about 28% of Amazon-fulfilled volume in 2029 and 50% by 2035. Amazon’s spokesperson confirmed the company is investing in faster delivery, while warning that the figures may change.

EMARKETER’s assessment of Amazon’s same-day strategy frames the competitive target clearly. Walmart says about 90% of the U.S. population lives within 10 miles of a Walmart or Sam’s Club. Amazon is trying to create comparable proximity without using thousands of general-purpose stores.

Local availability may become another competitive variable

Amazon has not told sellers how products would qualify for these facilities. Still, the operating logic points toward a familiar constraint: an ASIN cannot receive a very fast delivery promise if the unit is not near the customer.

That means national in-stock status may tell you less than regional availability. Two sellers could have the same total inventory and very different delivery promises if one seller’s units are positioned closer to demand.

This does not prove that Amazon will change the Featured Offer formula, storage limits or placement fees. Those would require separate announcements. The defensible inference is narrower: if Amazon makes local speed a larger part of the customer experience, sellers will need better demand forecasting by region and fewer stockouts on products selected for fast delivery.

Amazon already charges sellers to distribute inbound inventory through parts of its network. Our breakdown of how 2026 placement fees and other FBA charges stack onto each order is the right baseline for evaluating any future Mercury-related cost. Faster conversion is useful only if the extra placement, storage and replenishment expense leaves more contribution dollars.

Everyday products are the category focus

The reported facilities are intended to move groceries, household supplies, medicine and other frequently purchased goods. These categories reward availability and repeat buying more than a long-tail purchase that a customer makes once a year.

Amazon told investors that its same-day perishable service has attracted more monthly customers and larger baskets, according to EMARKETER’s summary of the company’s second-quarter comments. Those are company-reported results, but they explain why Amazon would spend heavily to move routine purchases closer to customers.

For sellers, category fit matters. A replenishable household product with steady local demand is more likely to benefit from this network than a slow-moving specialty item. Trying to force every ASIN into a local-speed strategy could increase stranded inventory and storage costs.

What sellers should do before any policy arrives

Do not change your inbound plan because of a 2031 projection. Use the report to improve the data you will need if Amazon begins exposing more regional signals or new same-day eligibility rules.

Start by measuring the conversion difference between delivery promises where Amazon already shows different speeds. Track stockout days, lost Featured Offer time and inbound lead time by ASIN. Separate products with predictable repeat demand from products that need a national pool of inventory to sell efficiently.

Keep bulk stock upstream where that is economical, then replenish FBA based on demand. EcomCrew’s guide to Amazon’s Q4 inventory cutoffs and AWD auto-replenishment option explains the current version of that decision. Mercury may make replenishment more granular later, but Amazon has not published that mechanism.

The next seller-relevant development will be something concrete: facility openings, an eligible-ASIN program, new placement options, regional inventory reporting or a fee change. Until then, treat Project Mercury as an indicator of Amazon’s likely strategy, not a rule you can implement against today.