Definition
IPI is Amazon’s Inventory Performance Index for professional FBA sellers. It summarises excess inventory, sell-through, stranded inventory and in-stock rate into a score that can affect restock limits. It is not a profit metric.
Worked example
Excess aged units and stranded listings drag IPI down even if sell-through on hero SKUs is fine. Removing or fixing stranded catalogue issues often moves the score faster than buying more stock.
Why it matters for replenishment
Low IPI can tighten how much you may send into FBA, which breaks replenishment plans that assumed unlimited inbound capacity.