Amazon FBA Reimbursement: Spot Lost and Damaged Stock Using AI

Download three reports for the same period (shipment receipts, the Inventory Ledger and the Reimbursements report), total them per product, and compare units sent against units received, sold, returned and reimbursed. Any gap Amazon has not paid for is a candidate claim. AI speeds up the comparison; filing it in time is on you.

The catch is time. Most of Amazon's claim windows are short: 60 days for loss or damage inside a warehouse, and 120 days at the outside for a customer return, far shorter than many older guides still say. Amazon also settles many defects itself before you look. So the aim is not to check everything forever. It is to run a tight monthly reconciliation, catch the exceptions while they are still claimable, and send each with evidence.

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Where the money leaks, in plain words

Stock held by Amazon passes through a few hand-offs, and units go missing at each: your supplier to your prep centre, the prep centre to the carrier, the carrier to the warehouse's receiving dock, the shelf to a picker, the buyer's return back to the shelf, and any removal order back to you. FBA reimbursement covers the stages that are Amazon's responsibility. Amazon splits them across four claim pages, each with its own rules: shipments to Amazon, fulfilment centre operations, customer returns and removals.

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Six leak types are worth looking for. A short receipt: you sent 400 units and Amazon says 392 arrived. A lost-in-warehouse unit: an adjustment line marks stock as lost with no matching reimbursement. A damaged-in-warehouse unit: the same with a damaged code. A customer return that never came back to sellable stock though the buyer was refunded. A removal order that arrived short, or whose tracking shows the carrier lost it. And a unit reimbursed at the wrong value, which is a different problem, covered further down.

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The three reports and what each one is for

Menu names move around Seller Central, so if a path fails, search the report name in the Seller Central search bar. The ledger's summary view already does half the reconciliation: the ending balance should equal the starting balance plus receipts, returns and found units, less shipments, lost, damaged and disposed units. Where it does not, its Unknown Events and In Transit Between Warehouses columns are the first places to look.

The claim windows on Amazon's own pages

Each claim type has its own help page and its own window. These are the figures on Amazon's pages as read on 5 November 2026.

• Shipments to Amazon (short or damaged receipts): once the shipment shows as eligible for investigation on its Contents tab, file no later than nine months after the verified delivery date. Amazon accepts only one claim per shipment, so make it complete.
• Lost or damaged in a fulfilment centre: within 60 days of the date the item was reported lost or damaged in the Inventory Defect and Reimbursement portal or the Inventory Ledger.
• Customer returns: no sooner than 60 days and no later than 120 days after the refund or replacement.
• Removals lost in transit: no sooner than 15 days after the last confirmed movement of the removal shipment, and within 75 days of the date it was created. Removals damaged in transit, or grading disputes: within 60 days of delivery to you.

Many third-party guides still quote longer windows from older rules, and some disagree with each other on returns. Copy the figures from the claim pages in your own Seller Central into the top of your spreadsheet and date-stamp them, because they can change. Everything below uses a "claim by" column filled from those pages.

A reconciliation walked through, with numbers

Say a cleaning company sells a branded 2 kg tub of descaler through FBA. In one month it sent two shipments and has these figures for the product (illustrative).

Work it as a short sum. Expected closing stock is opening 120, plus received 488 (300 and 188), plus returned 14, less sold 310, less lost 9, less damaged 6, which gives 297. Amazon reports 285, so 12 units are unexplained by any line above. That gap is the signal. Look in the ledger for "other" adjustments, units in transit between warehouses, or units sitting in an investigation status, and note the dates, because each one has a claim deadline.

Now the claims you can already see. Shipment B: 12 units short of the 200 sent, a receiving claim. Warehouse lost: 9 lost units, only 5 reimbursed, so 4 are unpaid. Damaged: 6 and 6, settled. At a $14 sourcing cost per unit (what the tub costs from the supplier, the basis Amazon uses for inbound and warehouse claims), the 12 and the 4 make 16 units, or $224 for one product in one month, with the unexplained 12 still to run down. Across 25 products at similar rates the yearly figure could reach thousands of dollars, but it depends entirely on your own error rate, so count your own before believing any sum.

Use a spreadsheet formula for those totals and use the AI to explain and prioritise the gaps. A chatbot will happily give you a total that does not add up, in a calm tone, so never let it be the calculator of record.

Prepare the data so the AI can read it

Reports are wide and noisy. Before involving AI, do three things in a spreadsheet. Filter the ledger to one month and drop columns you do not need (keep Date, FNSKU, ASIN, MSKU, Event Type, Reference ID, Quantity, Disposition, Reason and the fulfilment-centre column). Use a pivot table to sum quantity by SKU and reason. Then paste the pivot, not the raw rows, into the chat. If you are not confident with pivots, the data-cleaning tutorial covers the steps with AI help.

Then add three columns by hand for each SKU: units sent (from shipment records), units received (from the shipment view), and units reimbursed (from the Reimbursements report). That gives the AI a small table to reason about.

A prompt that finds candidates without inventing them

I sell on Amazon FBA. Below is a table, one row per SKU, for one month. Columns: SKU, units_sent, units_received, ledger_lost, ledger_damaged, reimbursed_lost, reimbursed_damaged, sourcing_cost_per_unit.

Do these steps and show your working:
1. For each SKU, compute short_receipt = units_sent - units_received.
2. Compute unpaid_lost = ledger_lost - reimbursed_lost and unpaid_damaged = ledger_damaged - reimbursed_damaged (never below zero).
3. Compute claim_value = (short_receipt + unpaid_lost + unpaid_damaged) * sourcing_cost_per_unit.
4. Rank SKUs by claim_value, largest first. Flag any row where a value is negative or any column is blank instead of guessing.
5. Do not say whether Amazon owes the money. Only list candidates for me to check.

DATA:
[paste table]

Here is a trimmed sample of what comes back (illustrative).

SKU DESC-2KG: short_receipt 12, unpaid_lost 4, unpaid_damaged 0, claim_value $224 (16 x $14)
SKU WIPE-50: short_receipt 0, unpaid_lost 7, unpaid_damaged 3, claim_value $50 (10 x $5)
SKU GLOVE-L: reimbursed_lost is blank. Cannot compute. Check the Reimbursements report.

What you fix: the third line is the model behaving well, because it refused to guess. Always read the flags first. Next, check the ranking by hand for the top three. Amazon's rules also treat a short receipt differently from a lost-in-warehouse unit, so group candidates by claim type before filing.

Matching each candidate to a claim type and deadline

Add a column "type" with one of: receiving shortage, warehouse lost, warehouse damaged, customer return not restocked, removal lost or short. Add "event date" (from the ledger) and "claim by" (event date plus the window for that type from your policy page). Sort by "claim by", not by value. A $50 claim due on Friday beats a $400 one due in six weeks, because the first disappears if you miss it.

A pest-control firm selling rodent bait stations, for instance, might find all its candidates are customer returns. Returned units that the buyer was refunded for, but that never appear back in sellable stock or as reimbursed, are the pattern. Those have a waiting period built in, since Amazon wants time for the item to come back, so the day-60 start matters as much as the day-120 end. If a refunded buyer never sends the item back within 60 days, Amazon's policy says it will in most cases charge the buyer and reimburse you without a claim, so check the Reimbursements report before you file.

Check before you file: four traps that waste cases

• Already reimbursed under another reason. The Reimbursements report can pay a unit under a different reason code or at a different time. Search by FNSKU and shipment ID across the full month, not just the same date.
• Found later. The ledger sometimes shows a "found" line that returns a lost unit to stock. If a unit was found, there is nothing to claim. Net the found lines against the lost lines.
• Disposed or transferred units. Units that were removed, disposed of at your request, or moved to another fulfilment centre can look like loss in a flat view. Check the event type.
• Reimbursed in stock, not cash. The Reimbursements report splits the quantity reimbursed in cash from the quantity reimbursed in inventory. A unit Amazon put back into your stock is settled even though no money arrived.

Building the evidence file

For each claim, keep a folder or a spreadsheet row that holds: the shipment ID and the shipment's contents list; the date it was created, the carrier tracking if any, and the delivery date; your supplier invoice or purchase record for those units, showing quantity and unit cost; the ledger rows that show the problem (screenshot or CSV excerpt); and the Reimbursements report line showing what has been paid, if anything. For shipment claims, Amazon's help page asks for proof of inventory ownership (a supplier invoice, a receipt from another seller, or a signed packing slip if you manufacture, showing the purchase date, product names matching the lost items and the quantity) and proof of delivery: active tracking IDs for small parcels, or for freight a proof-of-delivery document stamped by Amazon showing the box count and weight. Removal claims ask for photos of the unit, labels and boxes. Keep more than you think you need, for instance photos from your prep step showing the packed count.

A good habit that pays for itself: ask your prep centre or packer for a signed packing list with quantity per box. When 12 units fail to show up, a document that says 200 were packed is your answer to "how do we know".

Writing the case: a before and after

Amazon's claim tools ask for IDs and quantities and may ask for more detail. When you have to explain a discrepancy in words, or open a case with Selling Partner Support, the message should be short and factual. A model can draft it, but the facts must be yours. Prompt it with the claim sheet row and ask for facts only, no argument. Here is a typical weak first draft and the fixed one (illustrative).

WEAK:
Hello, you lost some of my inventory and I want to be reimbursed urgently. This is the third time. Please fix it. Thanks.

BETTER:
Subject: Reimbursement request, shipment ending 77, short receipt of 12 units

Shipment ID: [ID]. SKU: DESC-2KG (FNSKU [FNSKU]).
Units shipped: 200, as per the shipment contents and the packing list attached.
Units received per Seller Central: 188.
Difference: 12 units. Tracking shows delivery to the warehouse on [date] with all cartons signed for.
Please investigate the discrepancy and reimburse the 12 units at the current reimbursement value, or reconcile the difference in the receiving record.
Attached: shipment contents list, packing list, supplier invoice, ledger extract.

The better version names the IDs, states the numbers, says what you want and attaches proof. Leave out adjectives and history. If you have filed before without a result, say so in one sentence with the case number rather than as a grievance.

What to ask Amazon when the answer is no

Sometimes Amazon replies that it has found no discrepancy, or that you are outside the window. Reply once, with a specific request. Ask which ledger events the team used, what the received quantity was at check-in, and which fulfilment centre recorded the units. Amazon's pages say that if you disagree with a decision on the portal's Resolved tab, you can file a claim using the details shown there. Keep your tone factual, hold the case number, and follow the instruction on the case page about replying rather than opening a duplicate.

Value disputes: when the money is wrong rather than missing

A separate leak is a unit reimbursed at too low a value. Amazon's reimbursement policy values losses in two ways. For losses before a customer orders (shipments to Amazon, warehouse operations and removals) it reimburses the sourcing cost: what you paid the manufacturer or wholesaler, excluding shipping, handling and duties. You can enter that cost on the Manage Your Sourcing Cost page; if you do not, Amazon uses its own estimate. For customer-return claims it reimburses the refund or replacement value less applicable fees, and a valuation dispute must be filed within 60 days of the reimbursement. Amazon also caps any single unit at $5,000.

So if a garage selling a boxed set of car-care brushes that costs it $11 from its supplier sees units reimbursed at $7, the fix is to enter the real sourcing cost with the supplier invoice as proof, then dispute the low reimbursement. Do not inflate the cost: Amazon says it may decline a submission that is an outlier against similar products or its own estimate, or that rests on forged or altered documents, and a number you cannot document puts the whole account at risk.

A monthly routine that takes about an hour

1. First working day: download the three reports for the previous month plus the open-claims view.
2. Build the per-SKU table (a saved spreadsheet template with formulas, so the totals are never typed).
3. Run the prompt above on the table; read the flags before the ranking.
4. For the top candidates, check the three traps and add event dates and "claim by" dates.
5. File the earliest-deadline cases first; log case numbers in the sheet.
6. Two weeks later, re-pull the Reimbursements report and tick what was paid.

Once a quarter, add a longer view: which SKUs repeat? A product whose units keep going missing at receiving may be packed in a way that confuses the scanner, such as a loose bag inside a carton with no outer barcode. That is a prep fix, not a claim, and it saves more than any one claim does. The restock planning tutorial is where shipment sizing and cartons come in.

The accounting side

Reimbursements are income or a cost recovery, depending on how your accountant sets it up, and they arrive as lines in your settlement reports. Ask your bookkeeper how to code them, so they do not sit unexplained. If you use Xero or QuickBooks, the fees and payouts comparison explains how settlements land. Do not rely on AI for tax treatment; it is a question for a qualified adviser.

A second walk-through: refunded returns that never came back

A furniture maker selling a folding stool through FBA noticed refunds climbing after a heavy sales month. Pulling the returns data for the month, it listed 40 refunded orders. The ledger showed 31 units back in sellable stock and 4 as damaged and reimbursed. That leaves 5 units where the buyer was refunded, the unit never reappeared, and no reimbursement line exists. Amazon values return claims at the refund amount less applicable fees; at roughly $22 a unit after fees, that is $110. The prompt for this case differs slightly: ask the AI to match order IDs between the returns list and the ledger, and to output only orders that appear in the first and in neither of the others. Check the output by hand against the report for each order ID, because a matching error here means a claim for something Amazon already paid.

The timing rule bites hardest in this case. Amazon's window for return claims opens 60 days after the refund and closes at 120 days. Before day 60 the claim is premature, and Amazon may settle it automatically anyway if the buyer never sent the item back; after day 120 it lapses. Put both dates in the sheet, check the Reimbursements report at day 60, and file soon after if nothing has arrived.

How to check the process is paying for itself

After three months, add up what was claimed, what was paid, and the hours spent. If the hours cost more than the payments, the process is too heavy; narrow it to your twenty highest-value SKUs. If many claims are rejected for the same reason, such as "item was found" or "outside the window", change the checklist step that should have caught it. Track the proportion paid, not just the value, because a rising rejection rate usually means your evidence is thin or your dates are late.

What this approach cannot do

It cannot recover stock Amazon is not responsible for, such as units that expired in storage, loss in your own supply chain before the stock reaches the carrier taking it to Amazon, or refunds you issued to a buyer yourself, which Amazon's return-claim page excludes. It cannot beat a missed window. And it only works if your own records are tidy: without packing lists and invoices, the strongest finding is still only a suspicion. The AI is the fast calculator and a first-draft writer, nothing more. The reports are Amazon's, the deadlines are Amazon's, and the evidence is yours.

Keep an eye, too, on how Amazon's own assistants describe these cases; check any advice they give against the policy page before you act on it.

Questions about FBA reimbursement claims

Does Amazon not reimburse lost stock automatically?

Amazon resolves many lost and damaged units itself, and the Resolved tab of its Inventory Defect and Reimbursement portal shows those decisions. Defects it has not settled sit on the Eligible for claim tab, and some gaps, such as short receipts and removals that arrive short, only show up when you compare your own records.

How long do I have to file a claim?

It depends on the claim type. On Amazon's pages in November 2026: warehouse loss or damage within 60 days of being reported; customer returns between 60 and 120 days after the refund; removals lost in transit from 15 days after the last tracked movement to 75 days after creation; shipments to Amazon within nine months of verified delivery.

Can I paste my whole inventory report into ChatGPT?

A summarised extract works better than a raw dump. Large files exceed what a chat tool reads reliably and often get silently truncated. Filter to one ASIN or one month, or use a spreadsheet to total adjustments first, then ask the AI to explain the pattern.

Do I need a paid reimbursement service?

Not to start. The reports are free in Seller Central and the checks in this tutorial need a spreadsheet and a chatbot. Compare a service's fee with the hours you would spend yourself; services make most sense when your volume is high enough that your own time is the constraint.

What does Amazon ask for as evidence?

For a shipment claim, Amazon asks for the shipment ID, proof of ownership (a supplier invoice, a receipt or, if you manufacture, a signed packing slip, showing purchase date, product names and quantity) and proof of delivery: tracking IDs for parcels, or a stamped delivery document for freight. Removal claims also ask for photos.

Further reads

• Amazon FBA vs FBM Cost: Model Your Own Products With AI — Count lost-stock leakage in the FBA versus FBM sums.
• Amazon Buyer-Seller Messaging: AI Replies Within the Rules — Reply to buyers inside Amazon's messaging rules.
• Amazon A-to-z Guarantee Claims: Reply With AI-Drafted Evidence — Build evidence replies for buyer claims.
• Amazon Business Reports: A Weekly Review in ChatGPT or Claude — Add this check to a weekly reports routine.
• How to Sync Stock Across Shopify, Amazon and eBay Automatically — Keep counts aligned when you sell on several channels.
• Amazon Seller Virtual Assistant or AI: Which Tasks Go to Whom — A task-by-task split for Amazon sellers: what a virtual assistant should do, what AI should draft, what stays with you, and what each costs.
• Is AI Amazon PPC Software Worth It? Break-Even for Small Sellers — A break-even sum for AI Amazon PPC software, with fee-to-spend tables, a manual-review baseline and a one-campaign test plan.
• Amazon IPI Score: Find What Drags It Down With an AI Review — Export your FBA inventory data, have AI rank the SKUs pulling the IPI score down by excess, stranded stock, sell-through and stock-outs, then act.
• Amazon Plan of Action: Draft an Appeal With AI, Truthfully — Build a fact file first, then let AI draft the root cause, corrective actions and preventive actions strictly from your own records.
• Stock Count Variance: Find Why Your Count and System Disagree — A value-first routine for small shops: rank every count variance in dollars, then rule out the three cheap causes before you suspect theft.
• AI Tools and AI Development: The Complete 2026 Guide — the AI hub, including every tutorial in the AI-for-business series.

Sources: Amazon Seller Central help pages read 5 November 2026: FBA inventory reimbursement policy and its shipment-to-Amazon, fulfilment centre operations, customer return and removals claim pages; Amazon Selling Partner API documentation of the Inventory Ledger and Reimbursements report columns. Confirm the windows in your own account.