How to Cut Your Amazon ACoS by 40% Without Killing Sales
7 min read · 4 September 2026 · Calium Seller Services
A practical restructure: campaign architecture, negative keywords, bid rules and the 'harvest loop' our ad team runs every week.
Start with structure, not bids
Most high-ACoS accounts have one giant auto campaign. Split into: Auto (discovery), Broad (research), Exact (harvest), Product Targeting (defence).
The weekly harvest loop
Every Monday, pull the search-term report. Any term with 2+ orders and ACoS under target moves to Exact. Any term with 15+ clicks and zero orders becomes a negative.
Bid rules we use
- Top of search: +30% only for Exact winners
- Cut bids 15% on anything above 1.5x target ACoS for 14 days
- Never pause a keyword with a conversion rate above account average
Listing first
Ads amplify listings; they don't fix them. A 5% CTR improvement from a better main image beats any bid change.
Results
Across 60+ accounts we restructured in 2025, median ACoS fell from 34% to 20% within 8 weeks while sales rose 22%.
Need this done for you?
Talk to a Calium consultant.