What is Inventory Performance Index?

The Inventory Performance Index, usually shortened to IPI, is the score Amazon assigns to a seller's FBA inventory management. It is calculated for a store or region rather than per product, and it feeds the FBA storage capacity Amazon makes available to the account.

What goes into it

Amazon has published the components at various points, and has changed both the weightings and the qualifying threshold more than once. The components have generally covered:

• Excess inventory, the share of stock held beyond what current demand justifies
• Sell-through, units shipped relative to average units held
• Stranded inventory, units sitting in a fulfilment centre against a listing that cannot sell
• In-stock rate, how consistently your replenishable products stay available

Because the definition moves, the score and threshold shown in your own Seller Central account are the only authority. Any figure quoted elsewhere, including here, should be checked against it before you plan around it.

Why an advertiser should care

The score itself is a storage constraint. The behaviour it measures is a ranking constraint, and that is the more expensive of the two.

A stockout does not simply pause sales. It stops the sales velocity that organic rank depends on, and rank does not resume where it left off when stock returns. You pay to re-earn a position you already held. At the other end of the range, excess stock consumes storage capacity and cash without producing velocity.

Our doctrine makes the sequence binding: inventory cover is checked before any aggression at the top of search. A ranking push that runs a product out of stock has converted advertising budget into a rank loss.

Bid down rather than pause

When cover is short, lowering bids is preferable to pausing campaigns. A pause is binary and removes the listing from the auction along with its conversion signal. A lower bid slows spend proportionally, keeps some conversion flowing, and can be reversed smoothly when stock arrives. The same reasoning governs dayparting: a weak hour deserves a lower bid, not absence.

How Shurq handles it

The bidding engine derives days of supply from sellable stock divided by trailing sales velocity, sorts the result into zones, and applies the zone as a multiplier on the calculated bid. Where inventory data is unknown or has not been fed, the multiplier is neutral. Missing data is never treated as an emergency, because a bid cut triggered by an absent measurement is worse than no cut at all.