Lower ACOS by removing spend that produces nothing rather than by cutting bids across the board. Negate zero-order search terms, move proven converters to exact match, reduce bids only on keywords that convert below your break-even, and improve conversion rate on the listing. Across-the-board bid cuts lower ACOS by lowering sales, which is not the same as improving efficiency.
The wrong way
Cutting every bid by 30% will reduce ACOS. It will also drop you out of the placements that were producing your profitable sales, and total revenue falls with it. The metric improves while the business gets smaller.
The order that actually works
First, negate terms with meaningful clicks and zero orders — this is pure waste with no downside to removing it.
Second, reduce bids only on keywords converting worse than break-even, leaving profitable keywords untouched.
Third, improve the listing. A conversion rate improvement lowers ACOS on every keyword simultaneously without touching a single bid.
Fourth, check placements. Top-of-search often converts better and justifies its premium; product pages sometimes do not. Placement modifiers let you act on that difference.
Want this checked on your own account?
The free audit answers this question with your numbers instead of general rules — no Seller Central password needed.
Get my free audit