Category: Positive Sparks News
What do you do when Performance Max looks healthy in-platform, but your Shopping revenue quietly falls off a cliff? That was the exact problem we faced with a DTC ecommerce brand running both Standard Shopping and PMax at the same time.
The Problem
After launching Performance Max, the brand’s Standard Shopping revenue dropped 40%. Before PMax, Standard Shopping was generating roughly $42,000 per week. Within days of the launch, that number slid to about $25,000 per week, even though total account conversions did not collapse in the same way.
So what was happening? PMax was taking credit for demand that Standard Shopping was already capturing, especially around branded search behavior. On paper, PMax looked efficient. In reality, it was cannibalizing high-intent traffic we were already winning.
For ecommerce brands, that distinction matters. A reported ROAS can stay shiny while incremental revenue gets worse.
The Diagnosis
How did we confirm it? We ran a search term report segmented by campaign type and compared branded query coverage across Standard Shopping and Performance Max.
The pattern was pretty clear. Around 35% of PMax spend was going toward branded queries that Standard Shopping had already been covering effectively. In other words, more than a third of the PMax budget was not expanding reach. It was just intercepting demand that already existed.
That gave us a cleaner way to frame the issue for the client. This was not a “Google Ads is broken” story. It was a campaign-structure problem. PMax had too much freedom, no clear boundaries, and the wrong optimization signal.
The Fix
What changed once we had the diagnosis? We put guardrails in place.
First, we excluded branded terms from PMax using campaign-level negative keyword lists. That stopped PMax from spending against the easiest branded searches and pushed it away from traffic the account was already harvesting elsewhere.
Second, we created a dedicated PMax asset group built for non-branded, high-intent queries. That meant stronger creative alignment, tighter audience signals, and landing pages designed for shoppers who knew the product category but not necessarily the brand.
Third, we set campaign-level conversion goals so PMax optimized toward new customer acquisition rather than total conversions. That was the big shift. Instead of rewarding the system for scooping up existing demand, we told it to prioritize net-new value.
Actionable takeaway: if you’re running both Standard Shopping and PMax, check whether your goals reward incrementality or just volume. Those are not the same thing.
The Result
What happened next? Within 2 weeks, Standard Shopping revenue recovered to its baseline of $42,000 per week. PMax, now pointed at non-branded expansion, started generating an additional $8,000 per week in incremental revenue from new queries.
Blended ROAS also improved from 2.8x to 3.6x.
That combination is what we actually want to see in ecommerce accounts: the core campaign gets its stability back, the automation layer starts finding new demand, and the account-level efficiency improves at the same time.
If we break that down, the recovery in Standard Shopping plus the new $8,000 weekly contribution from PMax created an $18,000 swing versus the post-launch trough. That is the difference between “the dashboard looks okay” and real commercial improvement.
The Takeaway
Is Performance Max the problem? Usually not. Bear in mind, PMax is powerful, but it needs structure. In our experience, campaign-level negative keywords and clear conversion goals solve the majority of cannibalization issues. Honestly, we’d say they fix 90% of them.
So if your Shopping campaign weakens right after a PMax launch, don’t assume the channel suddenly stopped working. Ask a better question: is PMax creating incremental demand, or is it just re-labeling demand we already had?
That one question can save a lot of wasted budget.
If you’re running both campaign types, have you checked how much of your PMax spend is going to branded traffic? And if not, is this the week we finally put those guardrails in place?
( The Positive Sparks Team)
