IPI (Inventory Performance Index)

IPI determines how much inventory Amazon lets a seller store in FBA warehouses. Scores below 400 trigger restock limits — Amazon caps how much new inventory you can send in, which can choke growth even when demand is strong. The four components: excess inventory (too much sitting for too long), sell-through rate (units sold ÷ average inventory, last 90 days), stranded inventory (listings with stock but unable to sell, usually due to listing issues), and in-stock rate (the percentage of time your active SKUs aren't stocked out). The fastest way to lift IPI is removing or destroying slow-moving inventory rather than trying to liquidate it; the IPI math rewards velocity over recovered margin.