Why Is My Performance Max Campaign Cannibalising My Brand Search Traffic?

Performance Max cannibalises brand search when it’s allowed to compete on your own branded queries, the easiest, cheapest conversions in your account, and claims credit for sales that would have happened anyway through a free organic listing or a separate Brand Search campaign. This isn’t a glitch. It’s how Performance Max is built: the system optimises for conversions across every channel it can reach, and your own brand name is often the single highest converting search term available to it. Unless you tell it otherwise, it will chase that traffic every time.

The fix is a setting called brand exclusions, and most advertisers either don’t know it exists or set it up incorrectly. Below is how to confirm this is actually happening in your account, how to fix it properly, and when “cannibalization” isn’t really the problem at all.

How Performance Max ends up competing with your own brand

Performance Max doesn’t let you see or control individual keywords the way a Search campaign does. Instead, you give it a budget, some assets, and a conversion goal, and it decides where to spend across Search, Shopping, Display, YouTube, Gmail, Maps, and Discover. Because it’s judged on efficiency (cost per conversion or ROAS), branded searches look like free money to the algorithm: high intent, high conversion rate, low cost per click.

If you’re also running a dedicated Brand Search campaign, or relying on your free organic listing, Performance Max will often step in front of both. You end up paying for a click you would have gotten anyway, and your reporting shows Performance Max “driving” conversions that were really just existing demand getting rerouted through a different ad unit.

This tends to show up most clearly in a few situations:

• Your brand name has decent search volume and strong existing organic rankings.
• You run a separate Brand Search campaign at the same time as Performance Max, with no exclusions on either side.
• Performance Max’s overall ROAS or conversion rate looks unusually good compared to your other campaigns, often a sign it’s skewed by branded traffic rather than genuinely new demand.
• Your non-brand Search and Shopping campaigns have flat or declining conversions while Performance Max spend keeps climbing.

How to confirm it, rather than just suspect it

Before changing anything, check two reports:

1. Search terms insights (Performance Max): inside the campaign, under Insights, there’s a search terms breakdown that shows categories of queries driving traffic. If your brand name or close variations show up as a top category, that’s your confirmation.
2. Auction insights: compare your Performance Max and Brand Search campaigns against each other where possible. If both are showing up heavily on the same branded terms, you’re paying to compete with yourself.

If you don’t run a separate Brand Search campaign at all, this is worth investigating even more closely, because Performance Max may be quietly becoming your de facto brand campaign, inflating your overall account performance numbers while doing very little to find new customers.

The fix: brand exclusions

Google’s answer to this exact problem is brand exclusions, a setting that stops a Performance Max (or Search) campaign from serving on queries tied to a specific brand. You apply it by building a brand list and attaching it to the campaign:

• Go to the campaign’s Settings tab, open Additional settings, then Brand exclusions.
• Select an existing brand list, or create a new one and search for your own brand name (and common misspellings or variants).
• Save. You can optionally keep Shopping ads eligible to show on those same branded searches even with the exclusion in place, useful if you still want product listings to appear but don’t want the broader Performance Max ad types competing for the click.

You can also set brand exclusions at the account level so they apply across every eligible campaign automatically, under Campaigns > Content > Exclusions table > Edit exclusions > Account. This is generally the safer option if you manage several Performance Max or Search campaigns and want one consistent rule rather than remembering to apply it campaign by campaign.

It’s worth noting this is separate from ordinary negative keywords. Account-level negative keywords (found under Admin settings) also apply to Performance Max now, with a cap of 1,000 per account, but brand exclusions are the purpose-built tool for this specific problem and tend to be more reliable for blocking branded intent specifically.

When it isn’t actually cannibalization

Not every overlap between Performance Max and brand traffic is a problem worth fixing. A few cases where it’s fine to leave things alone:

• You don’t run a separate Brand Search campaign. If Performance Max is the only paid presence on your brand terms, it may simply be defending space a competitor would otherwise bid into, which is a legitimate job for it to do.
• Your organic listing is weak or inconsistent. If your site doesn’t reliably rank organically for your own name (common for newer brands, or ones competing against marketplaces and directories using the same name), paid coverage matters more.
• You’re comparing total account performance, not individual campaign performance. A brand click that converts at a high rate isn’t “wasted” spend if the alternative was losing that customer to a competitor’s ad sitting above your organic result.

The real test isn’t whether Performance Max touches branded traffic at all. It’s whether removing that traffic from its reporting would expose a much weaker non-brand performance underneath, which tells you the campaign’s real strength has been hidden rather than demonstrated.

Bottom line

If your Performance Max numbers look great but your non-brand campaigns are struggling, check the search terms insights report before trusting the topline ROAS. Add brand exclusions, ideally at the account level, so Performance Max is forced to earn its conversions from genuinely new demand rather than quietly collecting credit for people who were already looking for you by name.