For thousands of third-party sellers on Amazon, few things are more frustrating—or financially damaging—than discovering that their product listings have been randomly merged with a competitor’s product. This accidental merging, which often happens because of Amazon’s complex ASIN cataloging system, can lead to incorrect product descriptions, tainted customer reviews, lost sales, and even suspensions. In recent years, however, many merchants have found creative and effective ways to counteract this problem, protect the integrity of their listings, and safeguard their revenue streams.
TLDR:
ASIN merging is a persistent issue on Amazon where different products are combined under the same listing, causing confusion and financial loss for sellers. Merchants have begun solving this problem through brand registry, documentation submission, and proactive seller support engagement. Tools like flat files and unique UPC codes have also become vital for maintaining listing accuracy. Collaboration between sellers, legal action, and pressure on Amazon’s internal systems continue to be essential tactics for preventing unwanted merges.
Understanding the ASIN Merging Problem
The foundation of Amazon’s marketplace is its ASIN (Amazon Standard Identification Number) system. Each unique product listed on Amazon should be assigned an individual ASIN. However, when the algorithm—or in some cases mistaken human intervention—decides that two similar items are the same, it can merge their ASINs. This results in a single listing housing data from multiple sellers’ products. That listing might contain mismatched images, merged bullet points, and most damaging of all, jumbled customer reviews.
This can dramatically affect brand perception and product performance. For example, if your high-quality product is merged with a lower-quality knockoff, buyers might see poor reviews and choose another item, tanking your sales. Even worse, you may get negative feedback for issues you had no hand in creating.
How Merchants Identified the Root Causes
Merchants began addressing this issue by understanding where the problem originates. There are a few common scenarios:
- Listing Similarity: Algorithm-based cataloging sometimes flags similar titles or attributes (color, size, shape) as duplicates.
- Shared UPCs or GTINs: Some sellers unintentionally or fraudulently use the same UPC, which causes Amazon to believe the products are the same.
- Incorrect Reporting: Competitors may report other listings as duplicates in order to convert their reviews and ranking to their advantage.
Once merchants identified these sources, they focused on implementing step-by-step solutions to take back control over their listings.
Amazon Brand Registry: The First Line of Defense
The most effective tool sellers have used is Amazon’s Brand Registry. This program is available to trademarked brands and offers a layer of authority over listings connected to your registered brand. Once enrolled, sellers gain access to advanced reporting tools and stronger influence over listing content accuracy.
Brand Registry allows merchants to:
- Edit titles, bullet points, and images on their listings directly
- Submit grievances for incorrect merges
- Shield listings from edits by unauthorized sellers
This makes it far less likely that Amazon will mistakenly merge listings without input from verified brand owners.
Using Flat Files to Reassert Listing Ownership
Many advanced sellers turned to flat file templates (bulk product listing templates) to force Amazon’s system to recognize their products as distinct. With precise formatting and verified data tailored for each listing, they were able to override problematic merges.
Here’s how they did it:
- Created a catalog flat file CSV tailored for their product category
- Ensured all identifying data (UPC, product ID, brand, color, size) was correct and unique
- Submitted the flat file through Amazon Seller Central with a supporting case ticket requesting separation from a merged ASIN due to non-identical nature
Amazon’s automated system often defaults to merging listings with resemblance, but a properly filed flat file—with associated evidence—can serve as a compelling override.
Unique UPCs and GTIN Exemption Strategy
Another tactic involved the use of unique UPCs. Sellers found that shared or resold UPCs were a major trigger for fraudulent or mistaken merges. By purchasing legitimate GS1-registered UPCs tied directly to their brand name, they prevented cross-listing from affecting their catalog.
In some cases, merchants opted for a GTIN exemption, particularly for handmade or custom products. This exemption told Amazon their products didn’t require UPCs, which creates an additional barrier against automated merging.
The Role of Documentation and Legal Support
When flat files and registry utilization weren’t enough, some sellers escalated with formal documentation:
- Trademark Certificates to prove branding and listing ownership
- Product Images with unique identifiers and packaging
- Invoices and Manufacturing Specs showing product dimensions, weight, and design differences
Amazon teams, particularly the brand support staff, need explicit visual and written evidence that the two merged listings reflect fundamentally different items. In extreme cases, sellers turned to legal resources for cease-and-desist letters sent directly to Amazon or abusive competitors exploiting the ASIN-merge function to hijack reviews and rankings.
Collaborative Seller Networks and Forums
Uniquely, communities of sellers formed to counteract systemic issues like this. Sellers who dealt with persistent merging issues began sharing information in groups on platforms such as LinkedIn, Reddit, and Amazon seller forums.
By pooling knowledge, sellers discovered patterns in Amazon’s algorithm and effective escalation paths. These forums have documented thousands of examples and created templates for flat file submissions and support responses that significantly improve resolution chances.
Escalation Channels and Contacting Internal Amazon Teams
Persistent or repeated mergers often couldn’t be solved using general seller support. Experienced merchants learned to use specific escalation methods.
Key strategies included:
- Opening cases under “Report Listing Abuse” with attached evidence
- Contacting Brand Registry support cases with the ASIN, description of the issue, supporting flat files, and compelling comparisons between products
- Using contacts with Amazon Account Managers or via Amazon Transparency to flag serious catalogue issues
While the process can be time-consuming, persistence and thorough documentation usually lead to the problematic ASIN merge being undone within a few weeks.
Future Implications and Livelihood Protection
Amazon has taken steps to limit malicious or erroneous ASIN merges by implementing AI-driven catalog authentication and stricter enforcement of GTIN and brand match policies. However, the system is still prone to flaws, especially in niches with high seller competition and rampant counterfeit activity.
Merchants who rely heavily on Amazon for their livelihoods must remain vigilant. Documenting their products consistently, qualifying for Brand Registry, maintaining correct GTINs, and participating in seller communities have emerged as the best defenses against a system that still occasionally fails to protect product integrity out of the box.
Conclusion
ASIN merging is one of the most disruptive issues facing Amazon sellers today, but it’s not insurmountable. Through persistence, utilization of Amazon’s own tools, and comprehensive documentation, third-party sellers have reclaimed ownership over their listings and protected the reputation of their products. The most successful sellers in this scenario are the ones who are proactive, informed, and relentless in their efforts to maintain catalog sanity in a volatile marketplace.
