If you miss the 45‑day window, Amazon will still sometimes reimburse, but you lose leverage and predictability because you are now outside their “clean” investigation period.
For FBA lost or warehouse‑damaged inventory, Amazon’s 2025–2026 policy is to base reimbursement on your manufacturing/sourcing cost, not your selling price. In practice, they use either your documented cost (from invoices) or an internal estimated cost; they will not pay you retail.
The rough rule of thumb many sellers see is that reimbursement lands around your landed cost, sometimes slightly higher, but never more than Amazon’s internal cap per unit and never above your proven cost basis.
If you delay past 45 days, you risk Amazon classifying the units as ineligible or applying a lower assumed cost, so you may get less or nothingeven if the inventory was clearly lost.
Landed cost × 1.5. $10 COGS + $2 inbound = $18/unit reimbursed. File: Reports → Fulfillment → Reimbursements → "Lost in Transit."