At a glance
The shape of your Buy Box ownership over time on the ASINs that matter most. Where the win-rate card gives you today’s snapshot, this line chart shows the trajectory across the period for your top-revenue ASINs, so you can tell a sudden break (a competitor appeared, you went out of stock) from a slow erosion (a creeping price gap, a slipping seller metric). A 90-day line is long enough to see seasonal repricing wars and short enough to act on.
| What it counts | Buy Box win percentage plotted over the period for your top-revenue ASINs. Each point is the share of eligible Buy Box impressions you held on that day or interval, aggregated across the tracked ASIN set. |
| Why top-revenue ASINs | A point of Buy Box on a top seller is worth far more than a point on the long tail. Restricting the trend to the ASINs that drive revenue keeps the line meaningful and the alert actionable. |
| What “winning” depends on | Buy Box eligibility and share are driven by price competitiveness, fulfilment (FBA / Prime-eligible offers win more often), in-stock availability, and seller performance metrics (late shipment, order defect, valid tracking). A drop can come from any of these, not just price. |
| FBA vs FBM | The line reflects realised win share regardless of fulfilment. An FBM offer steadily losing to a faster FBA competitor shows as a declining trend. |
| Hijack / third-party offers | When a third-party seller starts offering on your ASIN, the trend usually shows a step-down on the day they appeared. Pair with ASINs with Third-Party Offers to confirm. |
| Out-of-stock effect | Days out of stock read as zero Buy Box share. A trend that crashes to the floor and recovers usually marks a stockout, not a pricing fight. |
| Reading the chart | Flat-and-high is healthy. A step-down is an event (competitor, stockout, metric breach). A gentle downward slope is erosion (price drift, ageing reviews, slipping metrics). |
| Currency / unit | percent |
| Time window | 90D (rolling 90 days) |
| Alert trigger | drop >5pp WoW (week-on-week fall of more than 5 percentage points) |
| Roles | owner, marketing |
Calculation
Calculated automatically from your Amazon Seller Central data. See the At a glance summary above for what the metric tracks and the worked example below for a typical reading.Worked example
A consumer-electronics brand on Amazon US tracking its top 20 revenue ASINs, 90-day window ending 01 May 26. All numbers illustrative.| Week ending | Aggregate Buy Box win rate (top 20) | Event |
|---|---|---|
| 06 Mar 26 | 94% | Baseline |
| 13 Mar 26 | 93% | Normal noise |
| 20 Mar 26 | 95% | Competitor briefly out of stock |
| 27 Mar 26 | 88% | New third-party offer appears on two ASINs |
| 03 Apr 26 | 82% | Competitor holds a lower price |
| 10 Apr 26 | 86% | Repricer matched, partial recovery |
| 17 Apr 26 | 71% | One top ASIN went out of stock mid-week |
| 24 Apr 26 | 92% | ASIN replenished, trend recovers |
| 01 May 26 | 93% | Back to baseline |
- The 27 Mar to 03 Apr fall is a competitor, the 17 Apr dip is a stockout. Both look like Buy Box loss, but the shapes differ. The competitor cost a sustained 6 to 12 points; the stockout was a sharp one-week crater that snapped back on replenishment. The fixes are completely different.
- The 17 Apr week breached the alert. Dropping from 86% to 71% is a 15pp week-on-week fall, well past the
drop >5pp WoWthreshold. Vortex IQ Nerve Centre flagged it, and the cause turned out to be inventory, not price. - Aggregating top-20 ASINs hides single-ASIN drama. A 15pp aggregate drop driven by one ASIN going to zero means that one ASIN cratered while the other 19 held. Drill into the per-ASIN view, Top Buy-Box-Loss ASINs, before reacting at the portfolio level.
- Partial recovery is a signal, not a victory. The bounce from 82% to 86% after the repricer matched shows the price move helped but did not fully reclaim the Buy Box. The remaining gap usually points to a fulfilment or metrics disadvantage, not price.
- Use the trend to set the right battle. A flat-high line means leave it alone. A persistent slope means investigate structurally (reviews ageing, metrics slipping). A step means find the event. The trend tells you which kind of problem you have.
Sibling cards merchants should reference together
The trend tells you the shape; these tell you the size and cause:| Card | Why pair it with Buy-Box Trend |
|---|---|
| Buy-Box Win Rate (top-50 ASINs) | The snapshot value behind the line. Use the trend for direction, the win-rate card for the current level. |
| Estimated Revenue Lost to Buy-Box Loss | Converts the trend into pounds, so you know whether a slope is worth fighting. |
| Top Buy-Box-Loss ASINs | Drills the aggregate line into the specific ASINs driving the move. |
| ASINs with Third-Party Offers | Confirms whether a step-down lines up with a new competitor appearing. |
| ASINs Stocking Out <7 Days | Confirms whether a crater is a stockout rather than a pricing war. |
Reconciling against Amazon Seller Central
Where to look in Amazon Seller Central:Seller Central → Reports → Business Reports → Detail Page Sales and Traffic by Child Item. The Buy Box Percentage column per ASIN is the underlying value. Run the report across a date range and plot the column to approximate the card’s line.Amazon does not provide a ready-made multi-ASIN Buy Box trend chart; this card aggregates and visualises the per-ASIN Buy Box Percentage over time for you. Timing, settlement, and reporting-lag table:
| Topic | Detail |
|---|---|
| Timezone | Business Reports use your marketplace account timezone; Vortex IQ aligns to your configured reporting timezone. Daily points near a boundary can shift by a day. |
| Daily aggregation | Amazon reports Buy Box Percentage as a daily figure; intraday swings (a competitor undercutting for two hours) are smoothed into the daily point. The card inherits that granularity. |
| Reporting lag | The most recent day or two may be provisional and can revise as Amazon finalises the daily aggregate. The tail of the trend can move slightly after first appearing. |
| ASIN-set changes | If your top-revenue ASIN set changes (a new launch enters the top 20), the aggregate line shifts because the basket changed, not because win rate changed. |
| Reason | Direction | Why |
|---|---|---|
| Aggregation method | Either | The card aggregates across the tracked ASIN set; a single-ASIN view in Business Reports will not match the portfolio line. |
| Top-N membership | Either | Different definitions of “top revenue” (last 30D vs last 90D) change which ASINs are in the basket. |
| Daily vs interval | Marginal | Rounding and interval bucketing can shift a point by a fraction. |
| Provisional tail | Ours may revise | The latest days revise as Amazon finalises; an early read can differ from the settled value. |
| Card | Expected relationship | What causes legitimate divergence |
|---|---|---|
ebay.active-listings | No direct peer. eBay has no Buy Box. Listing visibility on eBay is driven by Best Match, not a featured-offer contest. | Conceptual only. Do not expect the trends to track each other. |
shopify.total_revenue | Independent channel. A Buy Box slide on Amazon can quietly push demand to your DTC store. | No reconciliation; watch both to understand channel shift. |
Known limitations / merchant FAQs
Why is the line aggregated instead of per-ASIN? A single chart per ASIN across 50 ASINs is unreadable. The aggregate line gives you a portfolio health signal; when it moves, drill into Top Buy-Box-Loss ASINs for the specific ASINs. A drop fired the alert but my prices have not changed. Why? Buy Box share depends on more than price. The usual non-price causes are a stockout (share goes to zero), a new third-party offer, or a seller-metric breach (late shipments, order defects) that reduced your Buy Box eligibility. Check inventory and account-health cards first. The trend dipped and recovered on its own. Should I do anything? A self-recovering dip is usually a transient competitor undercut or a brief stockout. If it recovers within a week and does not recur, no action is needed. Persistent or repeating dips deserve investigation. Why does adding a new product change the whole line? The aggregate is computed over your top-revenue ASIN basket. When a new launch enters that basket, the mix changes and the line can step even though no individual ASIN’s win rate moved. This is expected. Can I change the alert threshold? Yes. Thedrop >5pp WoW default is configurable per profile in the Sensitivity tab. Tighten it if you run thin-margin ASINs where small Buy Box losses hurt, loosen it if your category is naturally volatile.