What is the Amazon Buy Box?

The Add to Cart box - the seller who holds it gets the sale.

The Buy Box (Amazon now calls it the Featured Offer) is the Add to Cart section on a product page. When several sellers offer the same product, Amazon picks one of them for that box - and since most buyers never open the full offer list, holding the Buy Box effectively means getting the sales.

Amazon rotates the box between eligible sellers based on price, fulfilment method, seller metrics and stock. For arbitrage sellers the practical lever is price: staying competitive without racing to the bottom, which is what a rule-based repricer with a floor price does around the clock.