ACoS tells you how a campaign performed. TACoS tells you whether the brand is compounding. If ad spend rises while organic share stays flat, you are renting revenue rather than building it.
For a launch phase product, a TACoS of 18–25% is normal for the first 90 days. Once the listing has review velocity and a stable conversion rate, healthy brands settle between 8% and 12%. Anything above 15% at maturity usually signals a conversion problem, not a bidding problem.
Segment by contribution margin band before you touch bids. A 42% margin SKU can absorb aggressive top-of-search placement; a 19% margin SKU cannot, no matter how good the keyword looks.
Practical loop: pull a 30-day TACoS by parent ASIN, sort by margin band, and only scale spend where organic rank has moved in the same window. If rank is flat and spend is up, pause and fix the listing.
