> ## Documentation Index > Fetch the complete documentation index at: https://docs.vortexiq.ai/llms.txt > Use this file to discover all available pages before exploring further. # Buy-Box Trend (top revenue ASINs), Amazon Seller Central > Buy-Box Trend (top revenue ASINs) for Amazon Seller Central. Tracked live in Vortex IQ Nerve Centre. How to read it, why it matters, and how to act on it. **Card class:** [Non-Hero](/nerve-centre/overview#card-classes-explained) • **Category:** [Buy-Box & Visibility](/nerve-centre/connectors#connectors-by-type) ## 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](/nerve-centre/kpi-cards/amazon-seller/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 | Five things to notice: 1. **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. 2. **The 17 Apr week breached the alert.** Dropping from 86% to 71% is a 15pp week-on-week fall, well past the `drop >5pp WoW` threshold. Vortex IQ Nerve Centre flagged it, and the cause turned out to be inventory, not price. 3. **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](/nerve-centre/kpi-cards/amazon-seller/top-buy-box-loss-asins), before reacting at the portfolio level. 4. **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. 5. **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)](/nerve-centre/kpi-cards/amazon-seller/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](/nerve-centre/kpi-cards/amazon-seller/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](/nerve-centre/kpi-cards/amazon-seller/top-buy-box-loss-asins) | Drills the aggregate line into the specific ASINs driving the move. | | [ASINs with Third-Party Offers](/nerve-centre/kpi-cards/amazon-seller/asins-with-third-party-offers) | Confirms whether a step-down lines up with a new competitor appearing. | | [ASINs Stocking Out \<7 Days](/nerve-centre/kpi-cards/amazon-seller/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. | **Why our number may legitimately differ from Business Reports:** | 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. | **Cross-connector reconciliation against other connectors the same seller may run:** | Card | Expected relationship | What causes legitimate divergence | | ------------------------------------------------------------------------ | -------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------- | | [`ebay.active-listings`](/nerve-centre/kpi-cards/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`](/nerve-centre/kpi-cards/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](/nerve-centre/kpi-cards/amazon-seller/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. The `drop >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. *** ### Tracked live in Vortex IQ Nerve Centre *Buy-Box Trend (top revenue 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](https://app.vortexiq.ai/login) or [book a demo](https://www.vortexiq.ai/contact-us) to see this metric running on your own data.