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Card class: Non-Hero • 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.
What it countsThe share of Buy-Box-eligible time (or sessions) you win across the top-50 ASINs by revenue, expressed as a 0 to 100% rate. A high rate means you are the featured offer most of the time on your best products.
Why top-50 revenueBuy-Box win rate matters most where revenue is concentrated. Tracking it across the whole catalogue dilutes the signal; the top-50 view keeps it focused on the ASINs that actually drive sales.
Sampling noteThe card samples the top-50 revenue ASINs and the result is cached for several hours to respect SP-API rate limits. It is a representative health read, not a continuous per-second measurement of every ASIN.
What moves itYour price versus competing offers, your fulfilment method (FBA / Prime eligibility helps), your seller metrics and account health, inventory availability, and the number and aggressiveness of competing third-party offers.
Why it mattersLosing the Buy Box on a top ASIN is close to losing the sale. A win rate below the target means a meaningful slice of demand on your best products is going to competitors.
Fulfilment scopeAll fulfilment, but FBA / Prime eligibility is a strong positive factor in winning the Buy Box, so a heavily FBM catalogue may show a lower rate on contested listings.
Time windowRT/7D vsP (a real-time read with a 7-day comparison against the prior period)
Alert trigger<85%. A win rate below 85% across the top-50 flips the gauge and notifies owner, marketing, and finance.
Rolesowner, marketing, finance

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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.
Segment of top-50Avg Buy-Box win rateNote
FBA ASINs (32 of 50)94%Prime eligibility helps win the Buy Box
FBM ASINs (18 of 50)67%competing against Prime offers and 3P sellers
Buy-Box Win Rate (top-50, this card)~84%weighted across the 50
Blended win rate (top-50)  =  ~84%
Alert                       =  FIRED (just below the 85% threshold)
7-day comparison            =  down from ~88% the prior week
Where the loss sits         =  the FBM ASINs (67%), dragging the blend below the threshold
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:
CardWhy pair it with Buy-Box Win Rate
Buy-Box Loss BurstThe crisis alert. This gauge is the steady level; the burst card catches a sudden drop in the same signal.
Buy-Box Trend (top revenue ASINs)The direction. A single win-rate reading is less useful than knowing whether it is rising or falling.
Estimated Revenue Lost to Buy-Box LossConverts the win-rate gap into a £/$ figure, the cost of every point of Buy Box you do not hold.
Top Buy-Box-Loss ASINsNames the specific ASINs dragging the rate down so you can act on the right listings.
ASINs with Third-Party OffersCompeting offers are the main reason you lose the Buy Box. This shows where the competition is.
Ad Spend on Out-of-Stock ASINsIf you are advertising ASINs where you no longer hold the Buy Box, that spend is largely wasted. Check both.

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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:
TopicDetail
TimezoneBusiness Reports use the marketplace’s local timezone; the card aligns its window consistently. Edge-of-window sessions can shift the reported percentage slightly.
Sampling and cachingThe card samples the top-50 revenue ASINs and caches the result for several hours to stay within SP-API rate limits. Amazon’s own Buy Box percentage aggregates over the period; minor differences are expected.
Eligibility effectsBuy-Box eligibility depends on price, fulfilment, account health, and inventory. A change in any of these (for example, a stockout) lowers win rate on the affected ASINs.
Period comparisonThe 7-day comparison contrasts the current rate with the prior 7 days. A re-pricing event mid-window can make the trend look sharper than a single day’s change.
Why our number may legitimately differ from Seller Central:
ReasonDirectionWhy
Sampling vs full reportEither directionThe card samples top-50 revenue ASINs with caching; Amazon’s report covers every ASIN over the full period. Aggregates can differ by a small margin.
ASIN set definitionEither directionIf you average Buy Box percentage across a different ASIN set than the card’s revenue-ranked top-50, the figures will not match. Use the same set.
Caching windowOurs can lag minutes to hoursBecause the read is cached, a very recent Buy-Box change may not be reflected until the next sample. The burst card is the real-time view.
Cross-connector reconciliation against other connectors the same seller may run:
CardExpected relationshipWhat causes legitimate divergence
amazon-ads.active-ads-on-no-buy-box-asinsSpend-efficiency tie-in. A low win rate on advertised ASINs means ad spend is going to listings where a competitor wins the sale. The Ads connector flags these directly.Different scope; the Ads card focuses on advertised ASINs, this gauge on top-revenue ASINs. They overlap where you advertise your best earners.
ebay.revenue-by-marketplaceMarketplace peer (loose). eBay has no Buy Box, but the idea of winning the featured / best-match position is analogous. Used as a conceptual peer.Entirely different mechanics; no shared data.

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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.