Someone else is probably selling on your listing right now, and it is costing you the quarter.
Unauthorized sellers are the most common problem I see in a first audit, and the one founders are most surprised by.
How it happens without anybody hacking anything
A distributor offloads stock. A wholesale customer clears out inventory. A liquidator buys returns. All of them can list against your ASIN, and if they price below you, Amazon can hand them the Buy Box you're paying ads to drive traffic to. Now your ad spend is buying their sales, on their inventory, with their fulfillment quality attached to your reviews.
The playbook, in order
1. Enroll in Brand Registry, properly — Transparency if your category justifies it, Project Zero if you qualify, and Brand Gating on your ASINs.
2. Test-buy the offer. You need proof of what they're actually shipping before you can enforce anything.
3. Report through Brand Registry with the test buy attached. Vague complaints get closed. Documented ones get action.
4. Fix the leak upstream. Tighten your distribution terms, because enforcement without a supply fix is a permanent game of whack-a-mole.
5. Monitor Buy Box win rate weekly, so the next one shows up as a number instead of a surprise.
61% win rate, and they thought conversion had collapsed
A brand we took on last year had three unauthorized sellers and a 61% Buy Box win rate. They thought their conversion had collapsed. It hadn't — they just weren't the ones getting the sale. Cleared in five weeks. Win rate back to 97%, revenue up 29%, ad spend flat.
You cannot optimize a listing you do not control. Do you know how many offers are live on your ASINs today?