Unauthorized Amazon Sellers: Trace Inventory and Stop Leaks

Consider a hypothetical brand that finds an unauthorized offer on its best-selling ASIN. The seller eventually disappears, but three weeks later another storefront offers the same product. A test purchase shows a lot code matching the earlier inventory. The brand now has a lead, not proof of a particular distributor's involvement. It still needs to trace where that batch went.

This guide covers that tracing work: what each clue can and cannot establish, how to record an investigation so it holds up, and which controls make the next leak easier to find. For the broader picture, see our guides to finding unauthorized resellers, removing unauthorized sellers through Amazon, and identifying gray market sellers.

Amazon generally does not remove a seller for being unauthorized. In a Seller Forums reply to a brand owner, an Amazon moderator stated that Amazon respects exclusive distribution agreements, but that violations of those agreements are not intellectual property infringement and that enforcement is a matter between the manufacturer and its retailers.

Under the first-sale doctrine, US trademark law generally permits the resale of genuine products that were lawfully placed into commerce. A reseller's lack of brand authorization does not automatically establish trademark infringement, even when an upstream distributor violated a contractual restriction. However, materially different products, interference with legitimate quality-control procedures, and other specific circumstances can create exceptions. Brands should have qualified counsel assess the evidence before pursuing a trademark claim.

That leaves the supply chain as the practical place to act. It also means reporting genuine resale as infringement works against you. Amazon's Project Zero eligibility criteria include at least a 90% acceptance rate on trademark reports filed through Report a Violation in the last six months, and enrolled brands must keep a 99% accuracy rate on self-service removals (verified October 2026). Inaccurate infringement reports can affect a brand's complaint acceptance rate and eligibility for Project Zero. Amazon considers the reporting history alongside additional eligibility criteria, so brands should submit complaints only when the evidence supports an actual IP violation.

Each supply route leaves a different evidence pattern. Knowing the pattern tells you which records to pull first.

Behind most of these routes sits what economists call a principal-agent problem. Your distributor is supposed to act in your interest, but its own incentive is to move volume. When a sale to a marketplace reseller helps a partner hit its numbers, the agreement is working against the incentive.

Treat every finding as an investigative indicator until independent evidence supports it. The biggest risk in this work is confirmation bias: settling early on a suspect and then reading each new clue as proof.

1. Make a documented test purchase. Buy as a customer would. Keep the order ID, purchase date, fulfillment method, shipping label, packaging, and any paperwork in the box.
2. Record the physical identifiers. Note lot numbers, batch codes, date codes, and serial or Transparency codes, then compare them against production and shipment records.
3. Read the packaging. Regional labeling, language, compliance marks, and barcode variants can narrow the likely route.
4. Note condition and quantity. Steady stock in current packaging is a signal worth investigating, not proof of a supply relationship. Small quantities in mixed condition point toward arbitrage or liquidation.
5. Ask the seller for sourcing documentation. Sellers may decline, and a refusal on its own does not establish misconduct.
6. Repeat the sample over time. One unit is one data point. Repeat purchases across several weeks either strengthen the hypothesis or break it.

What Lot Codes, Serial Numbers, and Transparency Can and Cannot Prove

Amazon Transparency assigns a unique code to each enrolled unit. Those codes support tracing only when your own records connect code ranges to specific shipments. A genuine unit that left your channel still carries a valid code. Our Transparency guide covers enrollment.

A consistent record turns scattered test buys into evidence you can act on. Log every case in the same format.

Define the confidence levels before you need them. Unconfirmed means one indicator, such as a single matching lot code. Partially supported means two or more independent indicators point to the same source, such as matching lot codes plus shipment timing. Substantiated means documentation directly links the inventory to an account, such as downstream invoices. Only substantiated cases should move to legal review.

Illustrative Example: Narrowing a Shared Batch

A brand finds three unauthorized offers on one ASIN. Test buys show identical lot codes, so the units likely came from one production batch, which shipped to two authorized distributors. The worksheet rates the case as unconfirmed. The brand then compares shipment quantities, delivery dates, regional packaging, and the distributors' reported sell-through. One distributor's orders exceeded its sell-through during the period, which moves the case to partially supported. This is a hypothetical scenario, not a client case.

A partially supported case justifies a conversation, not an accusation. Start with the rights your agreement already gives you, such as a request for downstream invoices or customer lists for the relevant lot. Ask about the shipment, not about the seller's guilt. Partners who are not involved usually answer quickly, and their records can clear them or point to the account that resold the stock.

Bring counsel in before any letter that alleges a breach, threatens termination, or names a third party. A formal notice based on a shared lot code alone can damage a relationship you need and create legal exposure.

Most investigations stall because the records were never built for tracing. Fix that at the source.

• Map identifiers to shipments. Record which lot, serial, or Transparency code ranges went to each account and on which date.
• Write explicit marketplace terms. Require written consent for marketplace resale, prohibit sales to buyers who resell on marketplaces, and require partners to pass these terms down the chain.
• Secure downstream visibility. A contractual right to request invoices or customer lists is worth more than a penalty clause, because it lets you establish where a unit went before anyone is accused.
• Control overstock and returns. Specify what happens to discontinued lines and returned goods, including certified destruction where appropriate.
• Watch the incentives. Volume tiers that reward buying rather than selling, regional price gaps, and dormant accounts on the authorized list all create room for diversion.

A minimum advertised price policy governs advertised pricing, not the price a reseller actually charges, and Amazon does not enforce it for you. Our Amazon MAP pricing policy guide covers what it can and cannot do. Have counsel draft and review any agreement, MAP policy, or termination. This article is operational guidance, not legal advice.

Some offers need a different route. Keep the distinction between legal claims and Amazon reporting categories clear, because they do not map one to one.

• Counterfeits: Report a Violation, or Project Zero if you qualify, after a confirming test buy. Our listing hijacking guide covers diagnosis.
• Materially different product: Expired, damaged, or altered goods sold as new may support a legal claim, but that does not mean every case qualifies for an Amazon IP complaint. Have counsel review the evidence before choosing a path.
• Listing content changes: Request a catalog correction through Brand Registry.
• Price pressure: Hold your floors rather than matching. See our price wars guide and dynamic pricing guide.

Monthly. Review the offer list on your priority ASINs and log every new seller with the date, price, fulfillment method, and storefront link.

Quarterly. Make documented test buys from the sellers holding the most inventory, update the worksheet, and audit your authorized account list against actual ordering.

Annually. Review distribution agreements and record-keeping against what the year's cases showed, and update terms at renewal.

Measure whether your investigation is working. Record the baseline number of unfamiliar sellers across priority ASINs, the number of new offers appearing each month, and the share of investigated purchases linked to a documented supply route. Track which cases are unresolved and whether affected ASINs continue experiencing unauthorized offers after corrective action. Compare the same ASIN group before and after changes rather than claiming success from one seller disappearing.

Repeated unauthorized offers warrant a review of the underlying inventory supply. Removing an individual storefront does not necessarily prevent other sellers from obtaining the same products. Tracking the seller activity and tracing inventory can help brands determine whether the problem is recurring diversion or separate, unrelated resale.