Product Cannibalization
When one of your products steals sales from another of your own.
Definition
Product cannibalization is when a new or existing product takes sales away from another product in your own catalog rather than from competitors, so total demand shifts internally instead of growing. On Amazon it commonly happens when a new variation or a near-duplicate listing splits demand, reviews, and rank with one you already sell.
Why product cannibalization matters for FBA sellers
A near-duplicate listing splits your review pool and rank across two pages, leaving both weaker than one consolidated listing. A new variation under the same parent shares the parent's review pool, but it still splits the individual child's rank signal and can have you paying for ads that bid against your own ASIN. The real danger either way is mistaking reshuffled demand for growth: total units barely move, but now they are spread thinner.
How cannibalization distorts your forecast
If you forecast each SKU in isolation, a cannibalizing launch makes the older SKU look like genuine demand decline when the demand simply moved next door. Forecast that way and you under-restock the original while over-buying the new variation. Forecast overlapping variations at the parent or family level so the total stays right even as the split shifts between children.
How to manage cannibalization in your restock decisions
Amazon's own tool for this is the parent-child relationship: genuine variations (size, color, count) belong under one parent so demand and reviews consolidate instead of fragmenting. Watch the family's combined sell-through rather than each child alone, and merge or remove accidental duplicate listings (same product, near-identical title and images) before they strand the original. Intentional cannibalization, like retiring an old version for a better one, is fine; the accidental kind quietly doubles your stranded-inventory risk.
Related terms
Spot a variation eating your sales
Inventory Hero tracks velocity and sell-through on every SKU, so when a new variation starts pulling from an existing one you see it in the numbers instead of mistaking it for lost demand.