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Card class: Cross-Channel • Category: Marketplace
Same SKU listed at materially different prices on OnBuy vs Amazon UK. MAP/brand-consistency risk.

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At a glance

Count of SKUs that are listed on both OnBuy and Amazon UK but priced more than 15% apart. A brand-consistency and MAP-policy risk: if Amazon’s price-policing crawler spots the cheaper OnBuy listing, the merchant’s Amazon listing can be suppressed under “Featured Offer disqualification” rules, costing more revenue than the OnBuy listing makes.
What it countsCOUNT(SKUs WHERE listed on both AND ABS(onbuy.price - amazon.price) / onbuy.price > 0.15). Drift is symmetric, OnBuy can be cheaper or more expensive; either direction triggers the count.
Direction skewOnBuy is cheaper than Amazon for ~80% of drifted SKUs in our sample. OnBuy commission (5 to 9%) is lower than Amazon (15%), so merchants who simply pass commission savings through to price end up cheaper on OnBuy. This is the MAP risk vector.
Source dataOnBuy GET /v2/listings (current price field) joined to Amazon SP-API Listing.attributes.list_price for the UK marketplace A1F83G8C2ARO7P.
Match key precedence(1) GTIN / EAN / UPC where available, (2) seller_sku, (3) manual ASIN cross-reference on the OnBuy listing. Match precision is the same as onbuy_xc_missing_on_onbuy.
Drift threshold15% absolute price gap. Below 15% is treated as normal price-discovery noise (rounding, occasional promo); above 15% is treated as a structural pricing issue requiring action.
CurrencyGBP only on both sides. Non-GBP Amazon listings (e.g. on A1PA6795UKMFR9 for DE) are excluded.
What “drift” really measuresPrice drift only, not title or image drift. Title and image divergence are surfaced separately under shopline_xc_catalogue_drift for the Shopline equivalent; OnBuy’s API does not yet expose image hashes for cross-channel comparison.
Time window30D rolling. Window is used to apply a stability filter, a SKU is only counted as drifted if its price gap has held >15% for at least 7 consecutive days, to avoid flagging deal-day fluctuations.
Alert trigger>10 SKUs drifting >15%. The integer threshold reflects scale; 1 to 10 drifted SKUs is normal noise; above 10 is a process issue.
Rolesowner, marketing.
Only whenhas_amazon_sibling = true.

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Calculation

Calculated automatically from your OnBuy data. 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 small UK kitchen-and-tableware seller, snapshot taken 27 Apr 26. The seller has 95 SKUs listed on OnBuy and 180 on Amazon UK. The matcher finds 78 SKUs listed on both. The drift comparison flags 14 SKUs above the 15% threshold:
SKUOnBuy priceAmazon UK priceGapCheaper on
KT-2104 (oak chopping board)£18.99£24.99-24.0%OnBuy
KT-2118 (linen tea-towel set)£14.50£19.99-27.5%OnBuy
KT-2202 (wooden serving platter)£29.99£39.99-25.0%OnBuy
KT-2450 (cast-iron skillet)£42.00£52.00-19.2%OnBuy
KT-3201 (ceramic mug, navy)£8.99£11.99-25.0%OnBuy
KT-3210 (ceramic mug, sage)£8.99£12.50-28.1%OnBuy
KT-3215 (espresso cups, set of 4)£24.99£34.99-28.6%OnBuy
KT-3224 (cereal bowl, set of 4)£21.99£29.99-26.7%OnBuy
KT-3301 (storage jar, large)£16.99£19.99-15.0%OnBuy (right at threshold)
KT-4102 (pasta bowl, white)£39.99£29.99+33.3%Amazon
(… 4 more rows …)
SKUs listed on both                 78
Drifted >15%                        14
Of which OnBuy cheaper              12 (86%)
Of which Amazon cheaper              2 (14%)
What it means for this seller. 14 drifted SKUs is above the alert threshold (10). The pattern is unmistakable: 12 of the 14 are cheaper on OnBuy by 19 to 29%. The merchant is passing the OnBuy commission saving (~7%) plus an additional 12 to 22% straight to the buyer, presumably to be price-competitive on the smaller marketplace. The risk is real and immediate. Amazon’s pricing crawler scans OnBuy weekly. When it finds a 25% cheaper listing on OnBuy with matching EAN, the Amazon listing’s “Featured Offer” (Buy Box) can be suspended under the “Fair Pricing” policy. For a merchant doing £40k / month on Amazon vs £6k / month on OnBuy, losing the Amazon Buy Box for even one of these SKUs (KT-2104 was the seller’s #3 SKU on Amazon at £980 / 30D) costs roughly 30 to 50% of that SKU’s Amazon revenue, vastly more than the additional OnBuy margin made by being 24% cheaper. The action is to lift OnBuy prices by 15 to 20% on the 12 cheaper SKUs to bring the gap inside the 15% safety band. The merchant will lose roughly 10 to 15% of OnBuy unit volume but stay safe on Amazon Buy Box, which is the right trade.

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Sibling cards merchants should reference together

This card is the marketplace-vs-marketplace pricing-discipline read. The natural pairings:
CardWhy it matters next to driftWhat the combination tells you
Amazon UK Top SKUs Missing on OnBuyThe “what to add” twin.Drift fixes the listings already shared; missing-on-OnBuy adds the ones not yet shared. The two cards together form a complete OnBuy catalogue audit.
OnBuy vs DTC Price GapThe DTC twin.If OnBuy is cheaper than both DTC and Amazon, the merchant is treating OnBuy as a deep-discount channel; rationalise pricing or accept the cannibalisation.
OnBuy Commission % of RevenueThe fee context.OnBuy’s lower commission tempts merchants to drop OnBuy prices; this card shows when that habit has grown into a MAP risk.
Listings Discounted >20%OnBuy-side discounting view.If the same SKUs show on both this card and Listings Discounted, the price is structurally low on OnBuy, not just drifted vs Amazon.
Avg Discount vs RRPThe average view.A high average discount on OnBuy with high drift count = OnBuy is the merchant’s discount channel by default.
Amazon UK Total RevenueThe downside risk.Quantifies what is at stake if Amazon Buy Box gets suspended (typical 30 to 50% revenue hit per affected SKU).
OnBuy Total RevenueThe upside being chased.Lets you size whether the additional OnBuy margin from being cheaper actually exceeds the Amazon risk (usually no).
Catalogue Drift vs Amazon (Shopline)The DTC-Amazon twin of this card.If both Shopline and OnBuy show drift vs Amazon, the merchant has a brand-wide MAP discipline issue, not OnBuy-specific.

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Reconciling against the vendor’s own dashboard

Where to look in OnBuy’s own dashboard: Neither OnBuy nor Amazon offer a built-in cross-channel pricing comparison; this is a Vortex IQ-only view. The closest manual workflow is:
OnBuy Seller Console (https://seller.onbuy.com) -> Listings -> All Listings (export CSV with prices) Amazon Seller Central -> Inventory -> All Inventory (export “Active Listings Report” with prices) Compare in Excel: VLOOKUP on EAN, calculate ABS(price_a - price_b) / price_a > 0.15.
Most merchants do not run this comparison until Amazon issues a “Fair Pricing” warning, at which point the listing is already suppressed and the revenue is already lost. Why our number may legitimately differ from a manual comparison:
ReasonDirectionWhy
Stability filterOurs lowerWe require the >15% gap to hold for at least 7 consecutive days before counting. A manual snapshot will catch deal-day flash-sales that we filter out.
Match key precedenceEitherManual comparisons usually match on seller-SKU; we match on EAN/UPC first. SKUs with EAN matches that have different SKU codes per channel are flagged by us but not by manual SKU-only comparison.
Variant rollupMarginalAmazon parent-ASINs with multiple child variants (size, colour) are flattened to per-variant rows; OnBuy listings are also per-variant. The variant tree shape matches in most categories but differs occasionally for apparel and footwear.
Time zone for “current price”MarginalBoth sides update prices through the day; we snapshot at sync time (every 6h for prices). A manual export taken at a different time of day can show a slightly different gap on SKUs the merchant is actively repricing.
Promo eligibilityEitherAmazon “Buy Box” price often reflects an active promo discount that does not appear in the listing’s list_price field. Our matcher uses list_price not featured_offer_price, which can under-count drift if the merchant runs heavy Amazon Lightning Deals.
Restricted brand listingsOurs lowerAmazon listings restricted under a brand-registry policy (where the merchant cannot freely reprice) are excluded from drift detection because the merchant cannot act on them.
Internal identity: onbuy_xc_catalogue_drift = COUNT(SKUs WHERE EXISTS(onbuy.listing) AND EXISTS(amazon.listing) AND ABS(onbuy.price - amazon.price) / onbuy.price > 0.15 AND drift_days_consecutive >= 7) The drift count and the per-SKU drill-down are derived from the same join; the count should always equal the row count of the drill-down table.

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Known limitations / merchant FAQs

What is “Amazon Fair Pricing” and how is it triggered? Amazon’s Fair Pricing Policy lets Amazon suppress a listing’s Buy Box (or de-list it entirely) if the same SKU is sold materially cheaper on another well-known retailer or marketplace. The triggers are not published precisely, but our experience says >15% cheaper consistently on a high-traffic UK marketplace will eventually trip the crawler. OnBuy is on Amazon’s monitored-marketplaces list. The cost of a Buy Box suspension is typically 30 to 50% of that SKU’s Amazon revenue; the saving from being cheaper on OnBuy almost never offsets it. My OnBuy listings are cheaper because OnBuy commission is lower; isn’t that fair? Yes structurally, no operationally. OnBuy commission is 5 to 9% vs Amazon’s 15%, so passing that 6 to 10 pp difference through is reasonable. The drift threshold here is set at 15%, which already accommodates the fee gap with margin. Once the gap exceeds 15%, the merchant is doing more than passing fees through; they are using OnBuy as a discount channel, which is what triggers the Amazon risk. Why is the threshold 15% and not 10% or 20%? 15% sits comfortably above the 6 to 10 pp Amazon-vs-OnBuy fee differential and below the rough 20 to 25% threshold where Amazon’s Fair Pricing crawler appears to flag listings. The middle band (10 to 15%) is where most well-managed merchants settle, large enough to pass fee savings through, small enough not to attract Amazon attention. The threshold is configurable per-merchant if a brand has a stricter MAP policy. Can the gap go in the other direction (OnBuy more expensive)? Yes, and the card counts both directions. OnBuy more expensive than Amazon happens for two reasons: (1) the merchant raised Amazon prices and forgot to update OnBuy (stale-listing problem), or (2) the merchant deliberately treats OnBuy as a higher-margin channel because OnBuy buyers are less price-sensitive. The risk side is lower in this direction (no Amazon Buy Box suspension) but it does cap OnBuy revenue; OnBuy buyers will simply not buy at the higher price. My count says 12 but I do not recognise the SKUs. What should I check? Open the drill-down view in Nerve Centre. The most common cause of “phantom” drift is a barcode mismatch: a SKU on Amazon has the wrong EAN entered, so our matcher ties it to a different OnBuy listing. The fix is to correct the EAN in Amazon Seller Central’s “Edit Product” view; the next sync will re-match correctly. How long does it take for Amazon to react after I fix the OnBuy price? Amazon’s price-policing cycle is roughly 2 to 4 weeks; reverting the OnBuy price typically clears any Buy Box suspension within that window. If a Buy Box is already suspended, the path back is to (a) lift OnBuy price, (b) wait 2 to 4 weeks, (c) if still suspended, raise it via Amazon Seller Central’s “Featured Offer ineligibility appeal” with the price-history trace. Does this card protect against MAP policy violations on the brand side? Partially. It catches gaps that Amazon’s crawler typically flags, which correlates strongly with MAP-violation risk on the brand side too. But MAP policies are brand-defined; some brands set a 5% MAP, others 20%. If the merchant resells branded goods, the merchant should set the drift threshold to the strictest applicable MAP across their brand portfolio, not the Amazon Fair Pricing rule of thumb. My drift count is zero but I know I have cheaper OnBuy prices. Why? The 7-day stability filter. If the price gap has held >15% for fewer than 7 consecutive days (e.g. a recent flash sale), the SKU is excluded. The card is meant to catch structural drift, not promotional pricing. If you genuinely want a same-day snapshot, use the per-SKU drill-down which has a “show all gaps” toggle.

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Tracked live in Vortex IQ Nerve Centre

Catalogue Drift vs Amazon UK is one of hundreds of KPI pulses Vortex IQ tracks across OnBuy 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.