Amazon lowered the minimum Inventory Performance Index threshold to 400 this year, and it feels like a gift until you read the fine print. Below 400, Amazon caps how much standard and oversize inventory you can hold in its warehouses, charges overage fees on anything past that cap, and can lock individual ASINs out of new inbound shipments. The threshold moved in sellers' favor. The consequences of missing it did not.
What Actually Moves the IPI Number
IPI is Amazon's blended score for excess inventory, sell-through rate, stranded inventory, and in-stock rate — and in mid-2025 Amazon tightened how it's applied. Standard storage allowances dropped from six months of forecasted sales to five, and Amazon reactivated ASIN-level restock limits on top of the account-wide cap. That means a single slow-selling SKU can now get its own inbound shipment blocked even while the rest of your catalog is performing fine. The score isn't just a warehouse-capacity gauge anymore; it's a per-listing gatekeeper.
400
Minimum IPI for unlimited storage
5 months
Storage allowance, down from 6
30–50%
Restock cuts at IPI 450–500
180 days
Aged-inventory surcharge trigger
Sellers sitting comfortably above 550–600 report stable or even expanded restock limits, which tells you where Amazon wants the whole seller base to land. The gap between "unlimited storage" and "capped and surcharged" is narrower than most catalogs can safely absorb, especially for sellers who lean on bulk inbound shipments to hit MOQ discounts from suppliers.
Why Storage Fees and Restock Limits Compound
A low IPI score doesn't just cap what you can send in — it makes the inventory you already have more expensive to keep. Monthly storage runs $0.87 per cubic foot for standard-size units from January through September and jumps to $2.40 during Q4. Miss your sell-through window and the aged-inventory surcharge now starts at 180 days instead of 271, adding $1.50 per cubic foot on top of the base rate. Hold units past 365 days and long-term storage fees can reach $6.90 per cubic foot. These charges stack — a single overstocked, slow-moving unit can be hit by three separate fees in the same month, which is exactly the kind of inventory that also drags your IPI score down.
| IPI Score Range | Restock Limit Impact | Storage Exposure | |
|---|---|---|---|
| 🟢 | Above 550 | Stable or increased | Standard rates only |
| 🟡 | 450–500 | 30–50% cuts reported | Approaching aged surcharge risk |
| 🔴 | Below 400 | ASIN-level caps, overage fees | Full surcharge stack applies |
The pattern in that table is the whole strategy: sellers who keep slow movers and overstock off Amazon's books entirely never let those units drag the score down in the first place. A 3PL that receives supplier shipments, holds the buffer, and feeds Amazon smaller, sell-through-matched restocks turns a liability into a non-issue — the excess units simply aren't sitting on Amazon's balance sheet accumulating penalties.
The sellers protecting their IPI score in 2026 aren't shipping less inventory — they're just not storing all of it with Amazon.
Questions to Ask Before Your Next Inbound Shipment
What's your current IPI score and trend
Pull it from Seller Central's Inventory Performance dashboard before planning any bulk restock — a score trending down changes how much you should send in.
Which SKUs are closest to the 180-day aged-inventory mark
Run an inventory-age report and flag anything past 120 days now, before the surcharge clock runs out.
Can your fulfillment partner hold overflow and ship smaller Amazon-bound batches
A 3PL that only preps for one big FBA shipment doesn't solve the problem — you need one that can meter inventory in over time.
How fast can stock move from 3PL storage to an FBA shipment
Ask for real transit and prep turnaround times, not the number on the rate card. A slow reroute means missing sell-through windows anyway.
Does the partner track sell-through data alongside you
The best partners flag slow movers before they hit the aged-inventory threshold, not after the surcharge posts.
None of this requires predicting Amazon's next policy change. Amazon publishes IPI thresholds and restock limit rules inside Seller Central, and the sellers avoiding caps and surcharges are the ones checking that dashboard monthly instead of finding out from a blocked shipment.
Not sure how much of your inventory should sit outside Amazon's warehouses?
OneDayBundle preps and stores overflow inventory, then feeds FBA restocks in sell-through-matched batches so your IPI score — and your storage bill — stay under control.
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