Amazon is flagging over 400,000 listings a day where the UPC or EAN doesn’t match the brand name registered in GS1.

This internal AI system (known to some teams as Bulldog) has been confirmed by multiple sellers, including Gwen McShea, and it’s changing how product legitimacy is enforced behind the scenes.

If your UPC prefix doesn’t trace back to your brand in GS1, your listing is a liability.

It’s easy to assume UPCs are just barcodes. But Amazon sees them as trust signals.
And if your brand name and UPC prefix don’t align, Amazon doesn’t just ignore it.
They penalize it.

Third-party barcodes, even if technically valid, are flagged if they don’t reflect brand ownership

Mismatched or recycled codes trigger suppression, catalog merges, or Brand Registry denials

GTIN mismatches can stall A+ content, product submissions, or even shipping eligibility

This isn’t theoretical.
We are working with a seller who lost 236 ASINs in a single sweep, with no warning.
No email. No performance notification.
And when we started reviewing his account, the only clue was buried in:
Seller Central > Manage Inventory > Listing Tools > Search Suppressed and Inactive Listings > Detail Page Removed

That case made us take a closer look at how widespread this issue really is.
Since then, we’ve been auditing UPC data for other sellers and spotting the same pattern: databases, mismatched prefixes, and silent suppressions hiding in plain sight.

So if you're unsure whether your UPCs align with your brand in GS1 (or if you’ve already seen strange listing behavior), we’re opening up time to help review and validate your catalog.

No assumptions. Just a clear, informed look at what might be putting your ASINs at risk.

Who needs to take action?
If you’re a brand owner:
Audit your UPCs immediately. If your GS1 license doesn’t match your brand name in Seller Central, your entire catalog could be vulnerable.

If you’re a reseller:
Partner with brands that have GS1 compliance, or prepare to lose your contribution rights when ASINs are flagged.

If you’re scaling a large catalog:
Segment listings by UPC source. Prepare a roadmap for UPC migration, especially across high-velocity SKUs or products with rich A+ content.

If your UPC doesn’t prove who you are, Amazon will assume you’re not the brand.

And that’s where control ends.

Curious if your listings are at risk? Just fill out the form in the comments or DM me.