CPCs spiked on one of our accounts and the first instinct was placement.
By Elizabeth Greene · September 2, 2026 · Curated by George's Blog
CPCs spiked on one of our accounts and the first instinct was placement.
Top of search must be slipping, right?
Not really.
We dug in.
Compared the two weeks before the spike to the two weeks after. Same bids and structure, same budget.
What changed was the search results page.
A competitor had launched with aggressive coupons across three of the top keywords.
Suddenly the auction got more expensive and conversion on those terms dipped because, honestly, a 20% coupon badge next to your listing changes the math for the shopper.
The ACoS spike was a competitive environment shift.
CPCs went up because the auction got hotter, and conversion went down because the click you were paying more for was now less likely to buy.
The thing is, if you just react by cranking top of search modifiers, you're going to make ACoS spike even more.
You're throwing money at a symptom.
What I actually want to know when CPCs jump is which product, which campaigns, and what changed externally.
BSR comparisons help here.
If your BSR is dropping but the category is stable, it's you. If everybody's BSR is kind of flat, it might be a category-wide thing. Search volume on your top keywords will tell you more.
Business reports will show you whether traffic dropped or conversion dropped.
Sometimes the answer is a competitor ran coupons for two weeks and then stopped, and your numbers normalize on their own. Sometimes it means you need to adjust your strategy.
But you can't know which until you find the root cause.
I just think people jump to placement way too fast.