Key takeaways
- Performance Max brand leakage inflates ROAS by blending existing brand demand with acquisition activity.
- UK ecommerce advertisers should rebuild Performance Max results without brand cost and brand conversion value before increasing budgets.
- Brand exclusions are not a first step. Build and confirm a separate brand campaign before removing brand from Performance Max.
- Negative keywords and brand exclusions solve different inventory problems, so the wrong lever creates confusing results.
- Measure total account revenue, spend, orders and new-customer orders for at least four weeks after any brand carve-out.
Performance Max brand leakage is one of the fastest ways to make an ecommerce account look healthier than it is. The campaign reports strong ROAS, finance sees revenue, and everyone assumes automation is scaling profit. Then you strip out searches for your own name and the non-brand return looks very different.
The mechanism is simple. Performance Max is rewarded for hitting your ROAS target, not for proving incremental demand. Your brand terms are cheap, warm and high-converting, so the system buys them unless you tell it not to. If your account structure does not separate brand demand from acquisition spend, the budget conversation is built on blended data. That is why our advice on campaign organisation for scalable growth starts with isolating what you are really trying to grow.
This is not a niche reporting problem. It changes budget allocation, target ROAS decisions, forecast confidence and board-level trust in Google Ads numbers.
What’s actually changed in Performance Max brand control
Advertisers now have enough visibility and control to audit the issue properly. Performance Max search terms can be pulled at individual query level for Search and Shopping inventory, including landing page and ad format detail. Campaign-level and account-level negative keywords are available. Brand exclusion lists give advertisers another lever for excluding specific brands from selected inventory.
That combination matters because the old defence for doing nothing was lack of evidence. You no longer need to accept a campaign-level ROAS figure and hope the system has made sensible decisions. You can classify branded queries, remove brand cost and conversion value, then calculate what the remaining non-brand activity actually delivered.
The change is not that Google has solved brand cannibalisation for you. The change is that you now have fewer excuses for leaving it hidden.
Why brand spend inside PMax distorts your ROAS
Performance Max brand spend distorts ROAS because it blends two different jobs into one number. One job is demand capture, where someone already knows your store and searches for it. The other is demand creation or acquisition, where the ad has to win a customer who has not already chosen you. Those two jobs do not deserve the same budget, target or success metric.
When brand terms sit inside Performance Max, the campaign can use them to prop up its average return. A £1 branded click that converts well makes a £4 non-brand click look more acceptable at campaign level. The blended ROAS rises, Smart Bidding gets more room, and budget increases follow. Money moves towards a campaign that appears efficient because it is part-funding itself with demand your brand already earned elsewhere.
That is where ecommerce teams make bad decisions. They raise budgets into a campaign that is not actually scaling new customers. They set target ROAS against a blended figure, so the non-brand side is expected to hit a number it has never proven. They pause Standard Shopping or Search campaigns that look weaker, even though those campaigns were doing the harder acquisition work.
The real question is incrementality, not attribution
Attribution asks which ad got credit. Incrementality asks whether the order still happened without the ad. Performance Max brand cannibalisation sits exactly in that gap. A branded paid click often deserves attribution inside Google Ads, but that does not mean it created the sale.
This is why brand-plus-product and brand-plus-discount queries need separate classification, not a lazy branded versus non-branded split. Someone searching for your brand and a product range has already narrowed their choice. Someone searching your brand plus discount code is often at the checkout stage. Paying full Performance Max rates to win those clicks makes acquisition reporting look better whilst doing little to expand the customer base.
The accounts with the most risk are ecommerce accounts using a single catch-all Performance Max campaign, a generous ROAS target and no separate brand Search campaign. We also see the problem where product feeds are strong, organic brand visibility is high, and the paid team reports only campaign-level ROAS. The campaign looks tidy. The economics are not. If your feed is where the value sits, our guide to shopping feed optimisation is worth reading alongside this.
PPC Geeks’ View
The specific problem UK advertisers will face is a false scaling signal. Performance Max brand traffic will make a campaign look ready for more budget when the non-brand portion is not profitable enough to carry that increase. That is how brands end up spending more without creating a meaningful rise in new orders.
In real campaign work, we see this most often in ecommerce accounts where Performance Max contains all products, all audiences and all funnel stages in one place. The tell is a strong campaign ROAS combined with flat total revenue, flat new-customer volume or a Search Console trend showing brand demand has not grown. The platform says performance improved. The business numbers say Google Ads has captured more of the same demand.
Brand inside Performance Max is not automatically waste. Hidden brand inside Performance Max is the problem, because it turns a budget decision into a guessing game.
— Chris S, Managing Director, PPC Geeks
A practical takeaway is simple: before you increase a Performance Max budget, rebuild its performance without brand queries. If the non-brand ROAS does not support the increase, fix structure before scaling. This is exactly the type of issue we look for in a free Google Ads audit, especially where automation, tracking or campaign structure is shaping the numbers.
The same thinking applies to competitive pressure. If competitors, affiliates or marketplaces bid on your brand, you still need brand defence. But that defence belongs in a campaign you can price, cap and read. Our competitive bidding strategy framework explains why Smart Bidding alone is not a strategy when auction pressure changes.
What advertisers should do next
Do not start by excluding your brand. Start by proving what brand is doing inside the account. Cutting first and measuring afterwards creates panic when reported ROAS drops, which is exactly what should happen when easy branded conversions are removed from the blend.
- Export Performance Max search terms this week. Pull the report by campaign and segment by ad format so Shopping and text ad traffic sit separately. Classify queries into pure brand, brand plus product, brand plus qualifier, brand plus competitor and non-brand. Use regex for brand misspellings and spacing variants.
- Calculate two versions of ROAS. First record the campaign’s reported cost, conversion value and ROAS. Then remove brand cost and brand conversion value. The rebuilt figure is the non-brand return you should use for budget decisions.
- Compare paid brand clicks with organic brand demand. Pull the same brand query trend from Search Console. If total brand demand is flat whilst paid brand clicks rise, Performance Max is capturing more existing demand rather than creating more demand.
- Build the brand campaign before exclusions. Create an exact and phrase match brand Search campaign with its own budget, bidding limit and ad copy. Confirm it serves before you apply exclusions or negatives. Otherwise you hand the top of the results page to the next bidder.
- Choose the exclusion lever by inventory. Use negative keywords when you need Search and Shopping query control. Use brand exclusion lists when the brand control needs to cover eligible Performance Max inventory. Keep Shopping visibility where it protects the top of the page.
- Measure account totals for at least four weeks. Track total spend, total revenue, total orders and new-customer orders. If revenue holds and spend drops, the removed spend was largely cannibalising existing demand. If orders fall by the removed brand order count, reinstate brand deliberately in its own campaign.
On the platform mechanics, Google’s brand exclusions in Performance Max documentation explains how brand lists apply across eligible inventory, and its guidance on account-level negative keywords shows where keyword exclusions actually take effect. For the wider debate on when Performance Max earns its place, the coverage on Google Performance Max at Search Engine Land is a useful, sceptical read. And Google’s own search terms insights for Performance Max confirms the query-level reporting the audit above relies on.
Once the leak is measured, rebuild the surrounding account so recovered budget has somewhere useful to go. That means separate non-brand Shopping or Search where the economics justify it, clearer product grouping, cleaner audience signals and reporting that splits brand defence from acquisition. If you need senior help making those calls, our Google Ads agency team can map the structure against margin, stock and new-customer goals.
What this means for your campaigns
Performance Max brand leakage is not a technical curiosity. It is a budget governance problem. If brand demand sits inside an automated campaign, Google Ads can hit a target by buying your warmest demand and presenting it as campaign success. That makes ROAS look safer than it is and pushes spend towards the wrong part of the funnel.
The right response is not a blanket ban on branded spend. Defend your brand when the auction demands it. Keep Shopping coverage when it protects valuable shelf space. But price that activity deliberately, separate it from acquisition, and stop using blended Performance Max returns to justify growth budgets.
The advertisers who act fastest will not be the ones who cut the most. They will be the ones who know exactly what their Performance Max brand spend is buying, what it is not buying, and which campaign should own each job.
If you’d like a second pair of eyes on how this affects your account, our team offers a free Google Ads audit, with no strings.
Frequently asked questions
What is Performance Max brand cannibalisation?
Performance Max brand cannibalisation happens when a PMax campaign buys clicks from people searching for your own brand. Those users already know you, so the campaign often gets credit for demand that existed before the ad.
Should I exclude my brand from Performance Max?
Exclude brand only after you have measured the leak and built a dedicated brand campaign. If competitors, affiliates or marketplaces bid on your name, you still need brand defence, but it should sit in a visible campaign with its own budget.
How do I measure a Performance Max brand leak?
Export Performance Max search terms, classify branded and non-branded queries, then remove brand cost and brand conversion value from the campaign totals. The remaining ROAS shows what non-brand activity is delivering.
Will ROAS fall after removing brand from Performance Max?
Yes, campaign ROAS will usually fall because easy branded conversions have been removed from the blend. Judge the change using total account revenue, spend, orders and new-customer orders, not the old campaign-level ROAS.
Are brand exclusions better than negative keywords?
They solve different problems. Negative keywords give query control on Search and Shopping inventory. Brand exclusions control eligible brand serving across Performance Max settings. Use the lever that matches the inventory you need to govern.
