Is PPC Cannibalization Killing Your Organic Amazon Profits?

Cannibalization means an ad receives credit for a purchase that would have occurred without it. You cannot establish that counterfactual from an organic rank or paid-sales percentage alone.

Use Ratios as Signals

ACoS is ad spend divided by attributed ad sales; TACoS is ad spend divided by total sales on a defined scope. A high paid share or rising TACoS can prompt investigation, but may also reflect a launch, seasonality, stock changes, or measurement differences.

Subtracting attributed sales from total sales does not necessarily identify a clean group of truly organic purchases. Align dates, products, advertiser scope, refunds, and attribution windows first.

Identify a Testable Hypothesis

For example, you might suspect a branded target has low marginal value because organic visibility is strong and competitor pressure appears limited. That is a hypothesis, not a reason to declare all its sales wasted.

Measure the Effect of a Bounded Change

1. Define a treatment, outcome, risk limit, and comparison plan in advance.
2. Change selected bids or spend while preserving other conditions where possible.
3. Compare total sales and contribution with an appropriate control or modeled baseline.
4. Allow for conversion/reporting lag and purchasing delays.
5. Repeat or reverse the test if the result is uncertain.

Interpret the Result Cautiously

Audience overlap and paths in AMC can guide hypotheses; they do not prove which impressions caused a purchase. Seller Scale recommends judging a change by incremental contribution after costs, not merely a lower TACoS. Moving spend to a different keyword creates another experiment, not guaranteed incremental sales.

Sources and Scope

The linked sources support the documented points above. Recommendations and hypothetical calculations are editorial guidance, not Amazon rules or promised results. Check the current requirements for your marketplace and account before acting.

• Amazon Ads attribution
• Amazon Marketing Cloud