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Metrics type: Supporting Metrics • Category: Marketplace

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At a glance

The percentage of time you hold the Buy Box across your 50 highest-revenue ASINs. The Buy Box is the featured offer behind “Add to Cart”, and the large majority of Amazon sales flow through it, so on a competitive listing this single percentage is one of the strongest predictors of whether your sales hold up. Where Buy-Box Loss Burst catches a sudden crisis, this gauge is the steady-state health read on your most important listings.

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Calculation

Calculated automatically from your Amazon Seller Central data. Top-50 revenue ASINs are sampled and the result is cached for several hours to respect SP-API rate limits. See the At a glance summary above for what the metric tracks and the worked example below for a typical reading.

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Worked example

A US consumer-goods seller, mixed FBA and FBM on amazon.com. Snapshot taken 17 Mar 26, with a 7-day comparison.
Four things to notice:
  1. 84% fired the alert, just. The blended rate slipped under the 85% floor, and the 7-day comparison shows it fell from about 88% the week before. A few points of Buy-Box loss across the top-50 represents real lost sales on the seller’s most important listings.
  2. The whole problem is on the FBM side. FBA ASINs win the Buy Box 94% of the time, helped by Prime eligibility, while the FBM ASINs sit at 67%. The blend hides this; the segmentation reveals that fulfilment method is the lever. Moving the contested FBM ASINs to FBA would likely lift the rate sharply.
  3. The 7-day drop is the actionable signal. A static 84% is one thing; a 4-point fall in a week suggests a competitor re-priced or new offers appeared. Pair with Buy-Box Trend (top revenue ASINs) to see whether the slide is continuing.
  4. The number is a cached sample, not a tick-by-tick feed. Because Buy-Box state is sampled and cached for several hours to respect rate limits, treat the figure as a reliable health read, not a real-time price-war monitor. For sudden events, the burst card is the live alert.
The seller moves the most-contested FBM ASINs to FBA for Prime eligibility and re-prices a handful where the margin allows. The blended win rate climbs back above 88% and the alert clears.

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Sibling cards merchants should reference together

Win rate is the steady-state Buy-Box health number. Pair it with the burst, the trend, and the financial impact:

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Reconciling against Amazon Seller Central

Where to look in Seller Central:
Business Reports → Detail Page Sales and Traffic by Child Item reports the Buy Box percentage per ASIN over the selected period. To reconcile, filter to your top-revenue ASINs and average their Buy Box percentages; the result should track this gauge closely, allowing for the card’s sampling and caching.
The live listing also shows whether you currently hold the featured offer, useful as a spot check on a specific ASIN. Timing and reporting-lag table: Why our number may legitimately differ from Seller Central: Cross-connector reconciliation against other connectors the same seller may run:

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Known limitations / merchant FAQs

What is the Buy Box win rate? The percentage of eligible time (or sessions) you are the featured offer, the one behind the “Add to Cart” button, across your top-50 revenue ASINs. Because most Amazon sales go through the Buy Box, a high win rate means you are capturing most of the demand on your best products. Why only the top-50 ASINs? Because that is where revenue is concentrated and where losing the Buy Box hurts most. A whole-catalogue average dilutes the signal with long-tail ASINs that barely sell. The top-50 view keeps the metric focused and actionable. Why is the number cached and not real-time? Buy-Box state on 50 ASINs would require heavy, repeated SP-API calls. To respect Amazon’s rate limits, the card samples the top-50 and caches the result for several hours. For sudden, real-time events, use Buy-Box Loss Burst. My FBA ASINs win the Buy Box but my FBM ones do not, why? FBA / Prime eligibility is a strong positive factor in winning the Buy Box. FBM offers competing against Prime-eligible offers, especially at a similar price, often lose. Moving contested FBM ASINs to FBA is one of the most reliable ways to lift win rate. What is the fastest way to recover Buy Box win rate? Three levers: price (match or beat the competing offer where margin allows), fulfilment (move to FBA for Prime eligibility), and availability (avoid stockouts, which forfeit the Buy Box). Account health also matters, a healthy account is favoured. Does losing the Buy Box ever happen with no competitor? Yes. If your price drifts above the Buy-Box-eligible range, or your account health dips, or you go low on stock, you can lose the Buy Box on your own listing with no third-party offer involved. The fix is to correct the price, metric, or stock. How do I see the money I am losing? This gauge gives the rate; Estimated Revenue Lost to Buy-Box Loss converts the gap into a currency figure so you can prioritise the fixes by financial impact.

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Tracked live in Vortex IQ Nerve Centre

Buy-Box Win Rate (top-50 ASINs) is one of hundreds of KPI pulses Vortex IQ tracks across Amazon Seller Central and 70+ other ecommerce connectors. Nerve Centre runs the detection layer; Vortex Mind investigates the cause when something moves; Ask Viq lets you interrogate any number in plain English. Start for free or book a demo to see this metric running on your own data.