Because Google’s PMax doesn’t play by traditional keyword rules anymore. It’s built to prioritize performance, not your campaign structure.
Here’s the deal:
Let’s say you’ve got Search campaigns running for specific keywords, and now you launch a Performance Max (PMax) campaign. Even if your Search ads are solid, PMax can still swoop in and grab impressions. Why? Because Google thinks PMax will convert better based on its wider net — user intent, behavior, placements across YouTube, Gmail, Display, etc.
Even if Search has your exact keyword, PMax might still take the lead if:
- It has higher predicted conversion value
- You’re not using exact match in Search
- Your bidding strategy favors PMax
- Your budget tilts toward PMax
How to take back control:
Use exact match keywords in your Search campaigns (Google respects those more).
Exclude branded terms from PMax if you want Search to own your brand traffic.
Segment products or audiences to split between Search and PMax (don’t let them compete).
Watch “Insights” and “Auction Insights” reports to see where overlap happens.
Bottom line?
PMax is smart but not always strategic. If it’s cannibalizing your Search traffic, you’ll need to step in and nudge Google’s automation back in line.
