PMax Brand Exclusions: The Setting Most Advertisers Miss

Performance Max (PMax) will happily serve on your own brand searches - competing against your dedicated brand-search campaign, driving up brand CPCs, and inflating PMax ROAS with revenue it didn't earn. Google introduced brand exclusions in 2023 to fix this, but the setting remains buried deep within the UI and defaults to "off" for every new campaign created.

For most advertisers, this default state leads to a silent drain on profitability. When PMax and a dedicated Search campaign compete for the same branded query, you pay a premium for a click you would have won anyway. In one recent engagement with a UK homewares brand, implementing proper brand exclusions saved the account £3,200 per month in unnecessary spend.

This article provides a comprehensive deep-dive into why this cannibalisation happens, the exact mechanics of how brand exclusions work across the Google ecosystem, and a step-by-step walkthrough to reclaim your brand-search efficiency and improve your overall Google Ads performance.

Why PMax cannibalises brand search (default behaviour)

Out of the box, Performance Max is designed to be "always eligible" for every auction Google runs - including searches for your own brand name. The underlying automation has no inherent understanding that "your brand + product" is a query you would prefer to route through a dedicated Search campaign with manual control and lower CPCs. Instead, it sees a query with a high conversion probability and bids aggressively to secure the conversion for the PMax campaign.

The cannibalisation mechanics are simple and frustrating for many UK eCommerce advertisers. Brand-search queries typically convert at rates significantly higher than generic terms (often between 8% and 15%). PMax's Smart Bidding algorithms identify these patterns and prioritise spend toward them to meet their ROAS targets more easily.

Beyond the CPC inflation, the primary issue is attribution. PMax attributes these high-converting brand clicks to itself, which artificially inflates the campaign's reported ROAS. This makes the campaign look more successful than it actually is on "cold" or generic traffic, masking poor performance in other areas like Display or YouTube placements.

Google introduced brand exclusions at the PMax campaign level in mid-2023 explicitly to address this. However, the setting is buried three levels deep in the campaign settings panel. This choice of UI design ensures that most advertisers remain unaware of the option, continuing to feed high-margin brand traffic through PMax where Google can capture higher CPCs than they would in a focused Search campaign.

What brand exclusions do (and don't)

Brand exclusions are a campaign-level setting that allows you to specify a list of brand names you do not want your Performance Max campaign to serve on. Unlike negative keywords in a standard Search campaign (which PMax famously makes difficult to implement), brand exclusions are a natively supported feature designed for this specific purpose.

What they actually do:

• Cross-Network Blocking: They prevent the PMax campaign from serving on Search, Shopping, and Display placements that Google classifies as being related to the listed brand terms.
• Preserve Search Campaign Priority: By removing PMax from the branded auction, you ensure your dedicated Search campaign has "first right of refusal" for those queries at the lowest possible CPC.
• Cleanse Your Data: They force PMax to find "incrementality" - revenue that wouldn't have come to the site otherwise - rather than piggybacking on existing brand equity.

What they don't do:

• Affect Other Campaigns: These exclusions apply only to the specific PMax campaign. Your dedicated brand-search campaigns will continue to function exactly as before.
• Guarantee 100% Elimination: Google's matching is based on their internal brand graph. Occasionally, very obscure misspellings or extremely niche brand + product combinations might still trigger an impression if they aren't explicitly in the exclusion list.
• Inherit Automatically: If you have five PMax campaigns, you must apply the brand exclusion list to all five individually. There is no account-level "switch" for brand exclusions.

It is also important to note that brand exclusions are different from "Keyword Themes" (which we will cover later). Brand exclusions are a hard block on specific entities, whereas keyword themes are a directional signal for where you *want* to serve.

Step-by-step brand exclusion setup

Setting up brand exclusions is a manual process that requires creating a brand list and then attaching it to your campaigns. We recommend doing this during the initial setup of any new PMax campaign, but it can be applied to existing campaigns at any time.

When creating your brand list, you aren't just typing in a single word. Google's Brand Library is a massive database of verified business entities. When you search for your brand, you are selecting that entity. If your brand is relatively new or niche, you may need to "Request a new brand" via the link provided in the interface. This process usually takes 3-5 working days for Google's team to verify and add to the library.

When brand exclusions matter most

While we generally recommend brand exclusions for almost every account, there are specific account structures and business scenarios where they are absolutely non-negotiable for maintaining profitability.

To understand if you are currently losing money to this cannibalisation, use our opportunity checker below. This tool uses your current PMax spend and estimated brand mix to calculate the potential monthly savings from moving that traffic to a dedicated Search campaign.

As noted in our comparison of PMax vs Standard Shopping, the level of control you sacrifice with PMax is significant. Brand exclusions are one of the few levers you have to regain that control without abandoning the performance benefits of Google's automation entirely.

Before/after client cost data

To illustrate the impact, let's look at real-world data from a UK-based homewares client. This client had been running Performance Max for six months without brand exclusions. They were also running a dedicated brand-search campaign, but noticed that their brand-search CPCs had slowly crept up from £0.45 to over £1.40.

The data was clear: PMax was competing for the same impressions as the dedicated Search campaign. This didn't just drive up the CPC; it also split the data between two campaigns, making bidding optimization harder for both.

The most important takeaway here is that total account conversions remained stable while cost plummeted. The £3,200 saved per month was immediately reinvested into a new PMax asset group targeting an underserved product category, which generated an additional £12,000 in monthly revenue that the brand previously wasn't capturing.

Note that the reported PMax ROAS dropped significantly. This is expected. PMax was no longer getting "easy wins" from brand traffic. However, the client's overall business profitability improved because they were no longer overpaying for their existing customers.

Verifying brand exclusions are working

Google Ads is notorious for "leakage," where exclusions don't always take effect as strictly as advertisers expect. After implementing brand exclusions, we follow a strict 14-day verification workflow to ensure the setting is being respected.

If you still see significant brand traffic in PMax after 14 days, it usually means your brand list is incomplete. Check for misspellings or secondary brand names (e.g., if you are "Global Widgets Ltd" but people search for "Global Widgets") and add them to the list.

Related settings: keyword themes exclusions

In late 2023, Google introduced another setting often confused with brand exclusions: Keyword Themes Exclusions (formerly known as "Topic Exclusions"). It is vital to understand the difference between these two settings as they serve different purposes in your PMax optimization strategy.

• Brand Exclusions: Block specific entities (Brand X, Brand Y). Used for controlling cannibalisation and competitor bidding.
• Keyword Themes: Block broad categories of search (e.g., "Jobs", "How-to guides", "Repair services"). Used for brand safety and avoiding non-commercial traffic.

For eCommerce brands, we typically use Keyword Themes to exclude queries related to "jobs," "refunds," or "complaints," ensuring PMax spend is focused strictly on commercial intent. These settings live in the same "Additional settings" panel as brand exclusions, so it is efficient to set up both simultaneously.

Common brand exclusion mistakes

Even seasoned PPC managers often stumble when implementing brand exclusions. Here are the five most common mistakes we see during our account audits:

• The "One-Word" Mistake: Only adding your primary brand name. You must include variations. If your brand is "Lumina Lighting," you also need to exclude "Lumina," "Lumina Lights," and "Lumina Shop."
• Forgetting Campaign-Specific Nature: Brand exclusions are not account-wide. If you launch a new PMax campaign for a holiday sale and forget to apply the brand list, that new campaign will immediately start cannibalising your brand traffic.
• Excluding Without a Backup: Never exclude your brand from PMax unless you have a dedicated Search campaign ready to catch that traffic. If you don't, you are effectively handing your branded search engine results page (SERP) to your competitors on a silver platter.
• Ignoring the "Request Brand" Feature: If your brand isn't in Google's library, don't just give up. Use the request feature. It is the only way to get a clean exclusion that works across all placements (Search, Shopping, Display).
• Panicking Over ROAS: As shown in our case study, PMax ROAS will drop. This is a "good" drop because it represents the removal of low-value, easy-win conversions. Don't let a temporary drop in campaign-level ROAS prevent you from making a decision that improves total account profitability.

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