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Metrics type: Cross-Platform Metrics • 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.

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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:
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:

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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-platform 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: 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.