What is a UPC “Letter of Affiliation”? (And Why Amazon Sellers Need One)

If you are launching a new product on Amazon in 2026, there is a good chance you’ve encountered a sudden, frustrating roadblock. You enter your brand name, you type in your newly purchased UPC code, you click save, and then… a red warning message appears.

"Error 8572: You are using UPCs, EANs, ISBNs, ASINs, or JAN codes that do not match the products you are trying to list."

Panic sets in. You might think, "Did I buy fake barcodes? Do I have to pay GS1 thousands of dollars now?"

Take a deep breath. Your barcodes are perfectly valid.

While this error isn't common for every seller, it does happen when Amazon's automated systems can't immediately verify the link between your brand and the barcode prefix. At UPCs.com, we solve this exact problem every single day using a document called a Letter of Affiliation (LoA). Having supplied over 500 million codes to businesses globally, we know exactly what Amazon is looking for to clean up these database mismatches.

Here is a complete, expert guide on what a Letter of Affiliation is, why Amazon demands it, and how it allows you to own your barcodes forever without paying annual renewal fees. If you are just getting started, you may also want to review our comprehensive guide on UPC codes for Amazon in 2026.

Why Does Amazon Flag a "Mismatch" Error?

To understand the solution, you need to understand the algorithm.

When you input a UPC into Seller Central, Amazon's automated system pings the GS1 GEPIR database to verify the code. If you purchased a Legacy Barcode (a barcode issued prior to the 2002 UCC settlement), that barcode is legally owned outright by the original purchaser, not rented.

However, a point of confusion for many is that the GS1 database still displays the original company's name. You might wonder, "When I search the GS1 database, why does a different company come up?" The answer is simple: the database reflects the original prefix holder, but the legal right to use those specific numbers has been transferred to you.

When Amazon’s bot sees that your brand name ("Smith’s Coffee") doesn't match the original prefix owner name ("Acme Corp") in the database, it may throw Error 8572 or Error 5461. Amazon isn't saying the code is fake; they are just saying, "We need proof that Smith's Coffee has the legal right to use Acme Corp's numbers."

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What is a Letter of Affiliation?

A Letter of Affiliation is a formal, legal document that bridges the gap between the GS1 database and your brand.

When we issue an LoA, it is a signed declaration stating that UPCs.com (the legal owner of the codes) has explicitly authorized your specific brand to use these exact UPC numbers. It establishes the "Chain of Custody."

When you open a case with Amazon Seller Support to resolve Error 8572, you will submit this letter. A human representative at Amazon will review the LoA, verify the relationship, whitelist your brand, and clear the error so you can publish your listing.

(For a step-by-step technical walkthrough on submitting this to Seller Central, see our guide: How to Fix Amazon Error 8572.)

Certificate of Ownership vs. Letter of Affiliation

A common point of confusion for new sellers is the difference between the two primary documents we provide. You need both, but they serve different purposes:

• The Certificate of Ownership: This is your receipt and proof of legal asset transfer. It states that you purchased the codes on a specific date and lists the exact numbers you own. You keep this for your internal records, and occasionally, retailers like Walmart or Wayfair may ask to see it to prove you didn't just guess a random number.
• The Letter of Affiliation (LoA): This is an external-facing document specifically formatted for Amazon's brand registry and catalog teams. It is focused entirely on brand authorization rather than financial ownership.

The "Own vs. Rent" Advantage

You might be wondering: "If this requires submitting a document to Amazon, shouldn't I just go directly to GS1 so the database matches my name perfectly?"

You certainly can, but it is going to cost you heavily in the long run. GS1 operates on a subscription model. They charge high initial setup fees (often hundreds or thousands of dollars depending on the prefix capacity) and mandatory annual renewal fees.

If your business hits a rough patch and you forget to pay your GS1 renewal fee, your barcodes are essentially deactivated. If you try to change them later, you have to recall all your physical inventory and reprint your packaging.

When you buy from UPCs.com, you are buying an asset, not signing a lease.

• One-Time Payment: You pay once, and you own the codes for life.
• No Hidden Fees: Zero annual renewals.
• Full Documentation: We supply the LoA and Certificates you need to satisfy major retailers.

How to Get Your Letter of Affiliation

If you purchase your barcodes through UPCs.com, getting your LoA is incredibly simple. Because we guarantee our codes, we provide this documentation to our customers to ensure a smooth listing process.

If Amazon flags your listing, simply reach out to our support team with your order number and the exact Brand Name you entered into Seller Central. We will generate a customized Letter of Affiliation and email it to you promptly so you can get your products live and start generating revenue.

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