Amazon FBA IPI: a real seller’s case study

This article provides a real seller's case study on Amazon FBA Inventory Performance Index (IPI), explaining why it matters in 2026, how to evaluate it, common pitfalls, and practical steps to maintain a healthy score. You'll get specific criteria, trade-offs, and actionable tips to apply to your own cross-border e-commerce business.

Why Amazon FBA Inventory Performance Index (IPI) Matters in 2026

Amazon's Inventory Performance Index (IPI) is a metric that measures how well you manage your FBA inventory. It directly affects your storage limits and fees. In 2026, with tighter warehouse capacity and higher storage costs, maintaining a healthy IPI is crucial for both sellers and buyers.

For sellers, a low IPI can lead to storage limits, which restrict how much stock you can send in, potentially causing stockouts and lost sales. For buyers, a seller with a low IPI may have frequent out-of-stock items, leading to a poor shopping experience. This case study shows how one seller navigated IPI challenges.

Amazon's official IPI threshold is typically 400, but the actual limit varies by warehouse and season. In 2026, the average IPI among sellers is around 350, with top performers scoring above 500. Sellers with IPI below 400 may face restrictions, but those above 500 often get unlimited storage (subject to capacity).

Understanding IPI is not just about avoiding penalties; it's about optimizing cash flow and customer satisfaction. A well-managed inventory means fewer storage fees, better buy box win rates, and faster delivery times.

• IPI affects storage limits and fees.
• Low IPI can cause stockouts and lost sales.
• High IPI leads to better customer experience and lower costs.

Key Components and Types of IPI

IPI is not a single number but a composite score based on four key factors: excess inventory percentage, sell-through rate, stranded inventory percentage, and in-stock rate. Each factor contributes to your overall score.

Excess inventory percentage measures the amount of inventory that has been in stock for over 90 days and is not selling well. Sell-through rate is the number of units sold compared to the average inventory level over a period. Stranded inventory percentage is the percentage of inventory that has listing issues and is not purchasable. In-stock rate is the percentage of time you have inventory available for a popular product.

There are no distinct 'types' of IPI, but sellers often categorize their products into fast-moving and slow-moving. Fast-moving products have high sell-through and low excess, while slow-moving products drag down your IPI. In this case study, the seller had a mix: a best-selling gadget with a high in-stock rate but also a seasonal item with excess inventory.

Typical IPI score ranges: Below 350 is considered risky, 350-400 is average, 400-500 is good, and above 500 is excellent. However, these are indicative and subject to Amazon's official updates.

• Excess inventory percentage (target < 10%)
• Sell-through rate (target > 70%)
• Stranded inventory percentage (target < 1%)
• In-stock rate (target > 90%)

How to Evaluate IPI: Criteria and Trade-offs

To improve your IPI, you need to evaluate each component. For excess inventory, you can run a clearance sale or create a removal order. For sell-through rate, you might need to adjust pricing or improve listing quality. Stranded inventory requires fixing listing issues, and in-stock rate demands accurate demand forecasting.

Trade-offs exist: lowering prices to increase sell-through can reduce profit margins. Removing excess inventory incurs removal fees. Increasing in-stock rate may require more frequent restocking, which increases shipping costs. In our case study, the seller decided to discount slow-moving items by 20% to clear them, which improved sell-through but reduced profit on those items.

The seller also used Amazon's Inventory Performance dashboard to track their IPI weekly. They set a threshold of 450 as a safety margin. When IPI dipped below 450, they took immediate action: they created a removal order for 500 units of the seasonal item and optimized the listing for the stranded inventory.

Another important criterion is the sell-through rate calculation: it's units sold divided by average inventory over a 90-day period. A rate above 70% is considered good. In-stock rate should be above 90% for top sellers. These numbers are indicative; Amazon may adjust them.

• Monitor IPI weekly using the dashboard.
• Set a personal threshold (e.g., 450) for action.
• Balance discounts with profit margins.
• Use removal orders for excess inventory.

Common Pitfalls When Dealing with IPI

One common pitfall is ignoring IPI until you get a warning from Amazon. By then, it's often too late to avoid storage limits. Another is over-reacting to a temporary dip by removing inventory too aggressively, which can lead to stockouts for fast-moving products.

Many sellers also misunderstand the stranded inventory metric. It's not just about listing errors; it can also be due to damaged inventory or missing SKU details. In the case study, the seller had 2% stranded inventory because of a missing image, which was easily fixed.

Another pitfall is not accounting for seasonality. A product that sells well in Q4 may have excess inventory in Q1, dragging down your IPI. The seller had this issue with a Christmas-themed item, which they managed by planning a Q1 clearance sale.

Finally, some sellers try to game the system by artificially inflating in-stock rate with small inventory levels, but this can hurt sales and buy box. The key is to maintain a balanced inventory that meets demand without overstocking.

• Don't wait for Amazon's warning.
• Avoid over-removing inventory for fast movers.
• Fix all stranded inventory issues promptly.
• Plan for seasonality in your inventory strategy.

Practical Recommendations and Next Steps

Based on this case study, here are actionable steps to improve your IPI. First, audit your inventory regularly: identify slow-moving items and create a plan to sell or remove them. Second, use Amazon's FBA Inventory Age tool to see how long items have been in storage.

Third, improve your demand forecasting using historical data and market trends. Fourth, consider using automated tools like RestockPro or InventoryLab to manage your inventory. Fifth, always keep your listings optimized to avoid stranded inventory.

For the seller in the case study, they implemented a weekly review meeting to discuss IPI metrics. They also set a rule: any product with an excess inventory percentage above 20% gets a price drop or removal order within 30 days. This simple rule helped them maintain an IPI above 450 consistently.

Finally, remember that IPI is a dynamic metric. Amazon updates it periodically, so stay informed about policy changes. In 2026, Amazon may introduce new factors, so be flexible.

• Audit inventory weekly.
• Use FBA Inventory Age tool.
• Improve forecasting with data.
• Consider automation tools.
• Review IPI metrics regularly.

Key Takeaways

In summary, Amazon FBA IPI is a critical metric that affects your storage limits and costs. By understanding its components, evaluating trade-offs, and avoiding common pitfalls, you can maintain a healthy score. Start by auditing your inventory, setting a personal threshold, and implementing regular reviews. Next steps: check your IPI today, create an action plan for any weak areas, and subscribe to Amazon's policy updates.

This article is compiled by kuajing168.cn for reference only. Please refer to the official announcements of each platform for the latest policies and rates.