What IPI Tier History Captures
IPI tier history is the rolling 13-week record of an FBA seller's Inventory Performance Index scores, plus the implied capacity tier each weekly score would produce. Amazon recalculates IPI every Sunday, and the resulting time series becomes the input Amazon uses to make storage capacity decisions through FBA Capacity Manager. The IPI tier history matters because Amazon does not act on a single weekly snapshot. It looks at the trend.
A seller with a 13-week IPI tier history bouncing between 480 and 620 is treated very differently than a seller holding flat at 580. Amazon penalizes volatility because volatility signals weak inventory control. Steady scores above 500 produce stable allocations; downtrends trigger automatic capacity cuts, even when the most recent score is still healthy.
IPI Tier History Thresholds and Capacity
Amazon does not publish exact tier thresholds, but observed seller data shows the following bands:
| 13-Week IPI Tier History Average | Capacity Treatment |
|---|---|
| 700+ | Premium tier, bonus capacity, auction priority |
| 500 to 699 | Standard tier, full default capacity |
| 400 to 499 | Caution tier, capacity may be capped at trailing baseline |
| Below 400 | Restricted tier, capacity reduced 15-30% versus baseline |
The weekly score is published to a 1000-point scale across three weighted inputs: Excess Inventory Percentage, Sell-Through Rate, and Stranded Inventory Percentage. Each weekly score feeds the 13-week trailing average. Refer to Seller Central for the latest documented thresholds.
Worked Example: Recovering from a Bad IPI Tier History
Your account has the following 13-week IPI tier history: 580, 590, 565, 540, 510, 470, 445, 430, 460, 480, 510, 535, 555. The trailing average is 513, the recent score is 555, but the trend is V-shaped. Amazon's algorithm reads this as a near-miss, not a recovery, and may keep capacity at the lower tier.
| Step | Action | Expected Effect |
|---|---|---|
| 1 | Run removal orders on aged inventory (181-270 day bucket) | +30 to +50 IPI points in 2 weeks |
| 2 | Liquidate excess on top 10 over-stocked SKUs | Improves Excess Inventory Percentage |
| 3 | Resolve stranded inventory (suppressed listings, FNSKU mismatches) | Stranded Inventory Percentage drops |
| 4 | Hold restock pause for 2 weeks on slow movers | Sell-Through Rate climbs |
| 5 | Result after 4 weeks | 13-week trailing average above 580, capacity restored |
The capacity restoration takes 4 to 6 weeks because Amazon weighs the rolling history. A single great week does not flip the tier. Sellers chasing IPI recovery need 3 to 4 consecutive weeks of strong scores to lift the average meaningfully.
Why IPI Tier History Is FBA-Specific
Generic supply chain platforms treat inventory health as a snapshot. Amazon treats it as a time series. The IPI tier history is unique to FBA because Amazon owns the storage cost and pricing model, and they explicitly trade capacity for inventory discipline. Sellers who understand the rolling 13-week mechanic intervene 4 to 6 weeks before a capacity cut takes effect.
The IPI tier history also interacts with the inventory aging buckets: aged stock simultaneously eats Capacity Manager allocation AND drives the Excess Inventory Percentage into the bad zone, which lowers IPI. Both feed back into capacity. Aggressive aging management is the highest-leverage IPI tier history fix.
Common Mistakes with IPI Tier History
Treating the current week's IPI as the source of truth. Amazon weights the 13-week trailing average. A score of 720 this week against a 13-week average of 480 will not unlock premium tier capacity.
Ignoring the V-shape penalty. A V-shaped IPI tier history (high, dip, recovery) is treated worse than a flat score at the dip's average. Amazon's algorithm penalizes volatility separately from level.
Waiting for the monthly capacity update before reacting. Capacity is set monthly based on the IPI tier history at the cycle start. Sellers who notice a slipping IPI in week 8 but wait until the next allocation cycle find themselves locked into restricted capacity for 30 days.
Frequently Asked Questions
What is IPI tier history?
IPI tier history is the rolling 13-week record of your weekly Inventory Performance Index scores. Amazon evaluates this history at the start of each storage cycle to determine capacity allocation through Capacity Manager.
How often does Amazon recalculate IPI?
Amazon recalculates IPI weekly. Each Sunday's calculation feeds into the rolling 13-week IPI tier history, and Amazon uses the trend to set storage capacity for the next month.
What IPI tier history score do I need to keep restock limits high?
Sustained IPI scores above 500 keep storage capacity in a stable tier. A 13-week IPI tier history that consistently shows scores above 600 unlocks bonus capacity.
Can I see my own IPI tier history?
Yes. Seller Central displays the last 13 weeks of IPI scores on the Inventory Performance dashboard, including the weekly score, rolling average, and component breakdown.