Buy Box share

Definition

The share of visits on which a marketplace shows this seller as the default add-to-cart option.

Why It Matters

On a marketplace that allows several sellers of the same item, almost all of the orders go to whoever holds the default position, so this share is closer to a revenue driver than to a metric. It moves with price, stock, shipping speed and account standing, which means it can fall for reasons a buyer inherits and did not cause. Ask for it by top item over at least a year, alongside the price changes in the same period. A business whose sales held while its share fell has been buying them back with price.