What Actually Happens to a 'Lost' FBA Unit
Inventory doesn't vanish — it moves through a chain of events, and each one leaves a record.
InviPulse ResearchJune 16, 20262 min left
"Lost inventory" sounds like a shrug — a unit that disappeared for no reason anyone can explain. In practice, it's the end of a fairly specific chain of events, and that chain is exactly what a reimbursement claim is built from.
The chain, in order
A unit typically arrives at one fulfillment center, then gets redistributed to others closer to demand. Every one of those movements generates an event record. "Lost" means one of those records doesn't reconcile — units received don't match units later available for sale, and no subsequent event (sale, return, disposal, damage) accounts for the gap.
The unit isn't missing from Amazon's system. It's missing from the story your own records tell about it — which is a smaller, more solvable problem.
— FBA inventory reconciliation notes
Where the gap actually shows up
| Event | What it should show | What a discrepancy looks like |
|---|---|---|
| Inbound receive | Units received matches units shipped | Received count is lower than shipped count |
| Inter-FC transfer | Units departing one FC match units arriving at another | A transfer departs but never arrives |
| Warehouse damage | A damaged unit is logged and removed from sellable inventory | A unit disappears from sellable count with no damage event |
| Customer return | A returned unit is received back into inventory or disposed | A return is processed but the unit is never re-added or logged as disposed |
The claim window is real but finite
Most claim types have a filing window measured in months, not years, from the date of the underlying event — not from when you noticed it. Reconciling on a regular cadence catches more of these before the window closes than an annual "let's check everything" pass ever will.
Building the claim
A reimbursement claim is essentially the discrepancy, packaged with the evidence: the expected count, the actual count, and the specific event log entries that show where the two diverge. Amazon's own reimbursement process reviews exactly that evidence — which is why a claim assembled directly from event data tends to move faster than one built from a general "some units seem missing" description.
The unglamorous truth is that most of this money goes unclaimed not because it isn't owed, but because reconciling fulfillment-center events against expected inventory, continuously, is exactly the kind of work that's easy to defer indefinitely. It's the same discipline behind making a settlement report reconcile at all — and open claims are one of the four numbers worth checking every week.