Preventing Bid Inflation in Amazon PPC Campaigns

Review the right metrics on a regular schedule

Bid inflation often appears as a slow rise in CPC or wasted spend before it shows up as a major ACoS problem. A weekly or biweekly review is usually enough to catch those shifts without overreacting to daily fluctuations.

• Cost per click: Watch for steady increases against stable or declining conversion rates.
• ACoS and ROAS: Flag campaigns that cross your target threshold for multiple periods.
• Wasted spend: Isolate clicks that produce impressions and spend but no orders.
• Search term spread: Note when a few terms begin consuming a larger share of budget.

Use negative keywords to control inefficient spend

Search term reports are the most direct way to see which queries trigger your ads. By filtering for high spend, high impressions, or low order volume, you can build a list of candidates for manual bid reductions or negative keywords.

For teams managing many campaigns, a tool such as the Amazon Negative Keyword Tool by Todoza can rank those search term candidates for review, but final bid and negative keyword changes should still be approved manually.

• Terms with high impressions and clicks but no orders
• Irrelevant or loosely related queries that do not match product intent
• Queries with ACoS well above target across multiple weeks
• Terms that consistently convert below the account average

When this matters

This type of review is especially useful for sellers or agencies managing multiple Amazon marketplaces and accounts. Small cost increases across many targets can be easy to miss when viewed only at the account level.

Teams with role-based workflows also benefit from a documented review process, because bid and negative keyword decisions are more consistent when they are based on shared performance data rather than isolated campaign edits.