Overview

In 2026 Amazon has tightened its FBA fulfillment parameters, making storage space scarcer and more costly. Sellers now confront stricter allocation caps, long‑term storage fees that activate after 180 days, and an Inventory Performance Index (IPI) that directly governs how much inventory they may keep on Amazon’s shelves. Ignoring these shifts can erode margins, so adapting forecasting, fee awareness, and storage‑program choices is essential for continued profitability.

Key Points

• Reduced allocation caps — Sellers with low IPI scores receive markedly smaller storage quotas, forcing them to turn inventory faster to retain any space.
• 180‑day long‑term fee trigger — Items that linger beyond six months incur escalating charges, penalizing slow‑moving SKUs more heavily than before.
• Elevated IPI influence — The IPI now determines the bulk of a seller’s storage entitlement, linking operational efficiency directly to selling capacity.
• Amazon Warehousing & Distribution (AWD) as a relief valve — AWD lets sellers park inventory outside the core FBA limits, providing a workaround for excess stock.
• 90‑day velocity metric dominates planning — Recent three‑month sales data better predicts demand than longer historical windows, especially in fast‑changing categories.
• Seasonal and promotional timing matters — Aligning inbound shipments with events like Prime Day reduces idle storage days and improves cash flow.

How the New FBA Rules Work

1. Allocation Adjustment — Amazon reviews each seller’s IPI each month; a score below the threshold shrinks the monthly cubic‑foot allowance, meaning the seller must either improve the score or ship less inventory.
2. Long‑Term Fee Activation — After an item has been stored for 180 days, Amazon adds a surcharge that rises each additional month, turning a modest monthly fee into a significant expense for stagnant stock.
3. IPI Calculation — Four pillars—sell‑through rate, excess inventory percentage, stranded inventory, and in‑stock rate—are measured; weak performance in any pillar drags the overall score down, tightening future allocations.