FNSKU Or Manufacturer Barcode: What The 2026 Barcode Rule Means For You

On 31 March 2026 Amazon ended commingling, and with it the arrangement that let some sellers ship units to FBA carrying nothing but the manufacturer's barcode.

For sellers who own their brand and hold the right role in Brand Registry it was a relief, because they can stop applying stickers to products that already carry a UPC. For resellers it went the other way, and every unit now needs an Amazon barcode whether the manufacturer printed one or not.

Both groups asked the same thing, which was what happens to the stock already in the network and to the shipment on the pallet. The answer depends on which side of the line your selling role puts you.

What stickerless commingled actually meant

Commingling was a fulfilment shortcut. When several sellers offered the identical product with the identical manufacturer barcode, Amazon treated those units as interchangeable and shipped whichever sat closest to the customer. Your unit went to somebody else's buyer, theirs to yours, and the accounting balanced at the end.

The trade for that speed was identity. A unit carrying only a UPC is a product, not your product, and once it joins a bin of everyone else's version there is no telling them apart.

Amazon's stated reason for ending the practice is that most sellers now keep inventory close enough to customers that the speed benefit no longer justifies it. Source: Seller Central, commingling practices will end effective March 31, 2026, Amazon primary.

An FNSKU works the other way. It is an Amazon barcode tied to your account and your SKU, so a unit carrying one can only be sold as yours, picked from your inventory and returned against your listing.

What changed on 31 March 2026

The announcement splits sellers into two groups, and the dividing line is a selling role rather than brand ownership in general.

Brand owners holding the Brand Representative role in Brand Registry no longer need to apply Amazon barcode stickers to products that already carry a manufacturer barcode such as a UPC or ISBN, which Amazon frames as flexibility, since those units no longer have to be pre-allocated to Amazon rather than another channel.

Resellers without that role are now required to use Amazon barcode stickers even on products that carry one. Both groups still label anything with no manufacturer barcode at all. The requirements apply to inventory shipped on or after 31 March 2026. Sources: Seller Central, Amazon primary, plus reporting from BellaVix, 2026.

The part that catches good operators is that enrolment alone is not the qualifying condition. The announcement names the Brand Representative selling role specifically, and sellers under a Reseller role have been asking in the same thread whether that counts. It does not appear to, so an account that looks enrolled can still sit on the labelling side.

Timing matters too, because Amazon ended its US prep and item labelling services on 1 January 2026, three months before this took effect. FNSKU labels now have to be produced somewhere other than a fulfilment centre, which we cover in our post on the 2026 fee changes.

How to tell if this is you

1. Check the selling role on your Brand Registry account rather than the enrolment status. The dashboard shows the role, and Brand Representative is the one the exemption names.
2. Look for the stickerless commingled setting on your SKUs. Manage Inventory shows the barcode setting per SKU, and anything still set to the manufacturer barcode comes first.
3. Find out who applied the labels historically. If the answer was Amazon, that route closed on 1 January 2026 and the plan needs a different owner.
4. Check for Used Sold as New complaints in the past year. Commingling is a common cause, and a SKU with that history is worth moving to FNSKU whichever side of the rule you sit on.
5. Look at what is already in the network. Units received before the change are a separate question from units you are about to send.

Why commingling produced Used Sold as New complaints

Under commingling, the unit a buyer received was not necessarily the unit you sent. If another seller's stock of the same UPC was closer, that is what shipped. When their stock was old, damaged, resealed, or a return that had been put back into sellable inventory, the buyer received it and complained on the listing they bought from, which was yours.

The complaint then describes a product you never handled. A defence built on your own quality control does not answer it, because your quality control was never involved in that shipment. Amazon records the complaint against the ASIN and the seller who took the order, and the buyer is describing what they received.

That is why moving a SKU to FNSKU is a root cause fix rather than an administrative preference, and why the evidence in a live complaint has to be about the fulfilment route rather than your warehouse. We set that appeal logic out separately in Used Sold as New.

What to check before you change anything

The urge to switch every SKU at once is worth a few days of thought, because changing the setting on a SKU with existing stickerless inventory creates two populations of the same product.

1. Confirm which SKUs have stock in the network. A setting change is cheap on an empty SKU and complicated on one with three thousand units already received.
2. Establish where the labels will be printed. In-house, at the supplier, or at a prep partner. Each has a different lead time, and the answer changes your next purchase order.
3. Check the manufacturer barcode is genuinely unique to the product. Recycled or duplicated barcodes are a separate catalogue problem, and they surface as a rejection at the worst moment.
4. Decide what happens to existing commingled units. They can be sold through or removed, and doing nothing means both populations coexist until the old stock clears.
5. Read the Brand Registry role before assuming the exemption applies. It decides everything else and takes two minutes.

Switching a SKU from stickerless to FNSKU

1. Change the barcode setting on the SKU. The path is Inventory, then Manage All Inventory, then the edit menu on the SKU. The change applies to units you send from that point rather than retroactively.
2. Print the FNSKU labels from the shipment workflow. Amazon generates the file when the shipment is created, so labels printed from an older file can carry a superseded FNSKU.
3. Cover the manufacturer barcode completely on each unit. A visible second barcode is the usual cause of a scanning error at receiving, and the error is attributed to the shipment rather than to the label.
4. Send the labelling specification to whoever does the physical work. Label size, placement and covering the original barcode all need stating, because a supplier who has never labelled for FBA assumes none of it.
5. Reconcile the first shipment carefully. The first inbound after a labelling change is where discrepancies show up, and catching them then is easier than reconstructing them a quarter later.
6. Watch the listing for condition complaints afterwards. If they continue once every unit in the network is labelled, the cause was something other than commingling.

We will not promise that switching to FNSKU clears an existing complaint, because a complaint already on the record is judged on the evidence attached to it. What the switch does is remove the cause, which is the part any appeal has to show.

How to keep this from becoming a receiving problem

1. Put the barcode decision into the new product checklist. Deciding at launch costs twenty minutes. Deciding after a container lands costs a relabelling job.
2. Keep the Brand Registry roles current. Roles change when staff change, and an exemption that depends on a role is only as stable as the person holding it.
3. Give suppliers the labelling specification in writing, per SKU. A factory printing from a spreadsheet sent last year keeps printing last year's FNSKU long after the SKU changed.
4. Audit a sample of received units quarterly. Buying one of your own units and looking at what arrives is the cheapest quality check available, and the account notifications carry the rest of the warning for anyone who opens them.

What we would do first if this were our account

Open Brand Registry and read the selling role, because that field decides whether this change made your life easier or added a step to every purchase order, and plenty of accounts have never checked it.

Then list the SKUs still set to the manufacturer barcode alongside their inventory position, since the ones holding stock are where sequencing matters.

After that the question is who physically applies the labels, and that needs a name rather than an intention, because inventory arriving unlabelled is a receiving problem. Keeping that decision matched to what is actually sitting in the network is a large part of our Amazon inventory management work.

We cannot promise that a condition complaint already on your record will clear, because that is decided on evidence rather than intent, and anyone telling you otherwise has not read enough of these. What we can tell you, before you spend anything, is which SKUs are exposed, whether your Brand Registry role gives you the exemption, and what the labelling needs to cost. That is what the free, no-obligation audit covers.

Related guides

• The 2026 fee changes and the end of FBA prep
• The barcode linked to more than one ASIN error
• Handling a Used Sold as New complaint

Common questions about FNSKU and manufacturer barcodes