Inventory Performance Index (IPI)
Definition
Amazon's score of how efficiently you manage FBA inventory, based on factors like excess stock, sell-through and in-stock rates. A low score can limit how much you can store.
Want a deeper explanation?
IPI is Amazon's version of inventory turnover. When it drops, Amazon limits capacity, which can cause stockouts on your best sellers.
Improving it means fixing the same things that improve cash flow: less excess, faster sell-through. Watch for: big inbound shipments ahead of peak season with no plan to clear older stock first.
Example
A brand with too much slow-moving stock sees its IPI drop, and Amazon cuts its storage capacity right before Q4.