Performance Max is bidding on your brand terms and charging you more than Search would

Performance Max is bidding on your brand terms and charging you more than Search would.

The mechanism is not obvious. PMax wins auction priority over Search campaigns in many configurations. When a branded query enters the auction, PMax can intercept it before your dedicated brand campaign competes. The reported search term often shows the brand name. The underlying dynamic shows PMax absorbing the impression at a higher CPC than a brand-specific Search campaign would have paid.

How to see it in your own account

The diagnostic is visible if you know where to look:

• Check your branded campaigns for impression share lost due to rank trending upward over the period PMax has been active
• Then check the CPC on branded terms across both campaign types
• A gap of 20 to 40 percent between PMax-served brand impressions and dedicated-brand-campaign-served impressions is not unusual
• Pull the Search Terms Insights report in the PMax campaign and check whether brand-related categories are showing up
• Compare branded conversion volume between PMax and your brand campaign over a 30-day window; if PMax has a meaningful slice, the interception is happening

The reported numbers do not look broken. PMax is showing conversions, brand campaign is showing conversions, both campaigns appear to be performing. The aggregate effect is that you are paying more for branded traffic than you would if PMax stayed out of the auction.

Why this happens by default

Google's official line is that PMax and Search "complement" each other and that auction logic resolves overlaps fairly. In practice, PMax has structural advantages in the auction:

• PMax has access to more signal types (audience, intent, behavioural) than a standard Search campaign, and can win on quality score factors a Search campaign cannot match
• PMax bids dynamically based on predicted conversion value, which on a branded query tends to be high (branded queries convert well), so PMax bids more aggressively
• The default account configuration does not include account-level negative keyword lists for brand terms

The combination means PMax behaves rationally for its goal (maximise conversion value) and the side effect is that branded traffic gets absorbed at premium CPCs.

The practical fix

The fix is not pausing PMax. It is adding account-level negative keyword lists that exclude your brand terms from PMax bidding.

Account-level negatives apply before the auction and prevent the interception from happening. This is different from campaign-level negatives, which only apply inside the campaign that has them.

To implement:

• Build an account-level negative keyword list containing your brand terms in exact, phrase, and broad match, plus common misspellings and brand-modifier combinations (brand name + product, brand name + city, etc.)
• Apply that list to your Performance Max campaigns (Tools, Shared Library, Negative Keyword Lists, then attach to PMax)
• Optionally apply the same list to non-brand Search campaigns where brand traffic should not appear
• Leave your dedicated brand Search campaign without the negative list so it can still serve

Most accounts do not have this in place. Not because practitioners do not know about negative keywords, but because the default assumption is that PMax and Search stay in their lanes. They do not.

What to actually do this week

• Pull your brand impression share lost (rank) for the last 30 days. If it is trending up since PMax launched, PMax is likely competing for the auction.
• Check Search Terms Insights in PMax for any brand-related theme clusters. Click through to see which queries are in the cluster.
• Compare the average CPC on branded queries in PMax vs your dedicated brand campaign. Use the Demographics or Audiences report in PMax for proxy data; exact CPC isolation is harder in PMax but the direction is usually clear.
• Build the account-level brand negative keyword list this week if you do not already have one.
• Apply it to PMax. Re-measure brand campaign impression share and CPC over the following 30 days.

The result of leaving this unfixed is a budget allocation that looks clean in reporting because the conversion still happens. The cost per branded conversion is just inflated by a campaign type designed for prospecting, taking credit for the easiest traffic in the account.

Check your brand impression share lost (rank) this week.

Is PMax running alongside a dedicated brand campaign in your account right now?

If you want a free check on whether PMax is intercepting your branded traffic, book a free audit and we will quantify the leak before recommending a fix.