Delivery Speed Now Outweighs Price in Amazon's Buy Box Algorithm, Analysts Confirm

Amazon's Buy Box algorithm has undergone a significant weighting shift, with delivery promise now correlating more strongly with customer satisfaction in Amazon's internal data than price, according to pricing analysts tracking marketplace algorithm changes through 2026.

By late 2025, Amazon had quietly raised the weight of delivery speed in its Buy Box formula from roughly 15% to 25-30%, while reducing price weight from around 35% to roughly 25%. Price tolerance also widened from 1% to 2-3%, meaning a Fulfilled by Amazon seller with a guaranteed Prime delivery window can now win the Buy Box at prices 8-12% above the lowest Fulfilled by Merchant offer.

For sellers relying on Fulfilled by Merchant logistics, the shift meaningfully raises the bar: competing purely on price against FBA sellers now requires pricing significantly below them to offset the delivery score gap, a margin difference analysts describe as having widened materially over the past 18 months. The takeaway for pricing and repricing strategy in 2026 is that price remains necessary but is no longer sufficient on its own to win Buy Box placement.