Performance Max: why your ROAS is inflated and how to reclaim your brand budget

As of: 22 October 2026.

Why Performance Max ROAS can lie to you

Performance Max can inflate your ROAS because, by default, it also bids on queries containing your brand name. Branded traffic converts unusually cheaply and often, since these are people who were already looking for you. The campaign claims those conversions and reports a spectacular return, when in reality it only intercepted sales you would have made with no ads at all. It's the same trap we covered in our piece on Google Ads and Meta Ads budgets: a high ROAS in the dashboard doesn't mean high profit in the bank.

The gap between 6.0x and 2.5x decides how much you can afford to pay to acquire a new customer. If you scale budget believing in a 6x return while you have 2.5x, you burn money at exactly the rate you top the campaign up. What ROAS covers your costs at your margin, you can check in the ROI calculator.

How many campaigns really cannibalize Search? The hard data

Performance Max overlapping with Search campaigns is the rule. In a 2025 Optmyzr study of more than 500 ad accounts, 91% of accounts had exact keyword overlap between PMax and Search, and 97% of PMax campaigns overlapped with search campaigns. In other words: if you run PMax and Search at the same time, they compete for the same queries with near-certainty.

Read the last three rows together. On keywords shared by both campaign types, conversion rate showed no significant difference in 74.9% of cases. Where there was a difference, classic Search won more often: in 18.9% of cases, versus 6.2% for PMax (Optmyzr, 2025). So the automation takes the traffic, and when results differ, it usually handles it worse than the Search campaign it just starved of budget.

Where the inflated ROAS comes from

An inflated PMax ROAS comes from three overlapping mechanisms: capturing branded traffic, last-click attribution, and a lack of search-term transparency. Each one alone shifts credit toward the automation; together they can inflate the reported return more than twofold.

• Branded traffic. PMax happily shows on brand-name queries because they have the highest conversion rate in the whole account. These are the cheapest conversions that exist, and the automation claims them first.
• Fuzzy match. PMax matches queries broadly, so it also picks up misspellings and name variants (e.g. "zets" instead of "zest"). According to Google, brand exclusions also block misspellings, but they cover only brands on Google's list: if yours is missing, you have to request it.
• Opaque search terms. Until recently PMax didn't show which queries it served at all. Even today the report is trimmed, so it's hard to prove how many conversions are new acquisition versus intercepted traffic.

How to check whether your PMax is burning brand budget

To check how much brand budget your Performance Max is burning, compare branded conversions before you launched PMax with the period after. If PMax "delivered" conversions but the total number of brand-name transactions didn't rise, the campaign only took over existing traffic and added no new demand.

• Open the search-terms report (Insights → Search terms) and measure what share of clicks and conversions comes from queries containing your brand name.
• Compare the PMax conversion rate with your branded Search campaign. If they're similar, PMax is probably living off branded traffic.
• Check the trend of branded conversions over time: after PMax launched, did their total grow, or did they just "flow" from Search into PMax?
• Recalculate ROAS after excluding revenue from branded queries. That's your return on new-customer acquisition, and that number should drive your budget decisions.

Revenue attributed to the campaign is not yet profit. To see profit, connect this data to a dashboard that links ad spend with sales and margin. Only then will you see whether that "6x ROAS" from PMax actually leaves anything in the bank.

Brand exclusions — how to set them and why they aren't enough

Brand exclusions in Performance Max cut the campaign off from queries containing your name in Search and Shopping inventory. According to Google Ads Help, they also block misspellings and brand searches in other languages, and Google advises monitoring their impact on reach and performance. Treat them as a first filter: branded traffic still needs its own campaign and a regular check in the search-terms report.

• Enable the brand exclusion list at the PMax campaign level (Settings → Brand exclusions) and add your company name and main product names.
• Check the search-terms report for unusual name variants that slip past the exclusions, and exclude them with negative keywords.
• Keep a separate branded Search campaign so you consciously control brand traffic instead of handing it to the automation at a discount.
• After every change, return to the search-terms report and verify the exclusions actually work.

When Performance Max actually earns its budget

Performance Max truly earns its budget when you measure it on new-customer acquisition. Set the "new customer acquisition" goal (in "New customer only" mode the campaign bids only for new customers), cut off branded traffic with exclusions, and judge the campaign on the cost of winning a customer you didn't have before. Then PMax's automation across the display network, YouTube and Discover can deliver results that manual campaigns won't reach.

For an e-commerce store with a broad catalogue and a well-maintained product feed, PMax is often the most effective tool for scaling prospecting. The problem almost never sits in the tool. It sits in measuring it against a number it inflates for itself. Fix the measurement and the "PMax vs Search" fight becomes a simple division of roles: Search guards branded traffic, PMax hunts for new customers.

At Zest we treat Performance Max like any other campaign: first we separate branded traffic from new-customer acquisition, and only then judge the return. The Falcon Car Rental case study shows what cutting inefficient traffic looks like on a live Google Ads account. If you want your budget to work for new customers, see how we run Google Ads campaigns, or explore how our digital marketing agency measures return.

How to structure the account so PMax doesn't eat your brand

To stop Performance Max from eating your branded campaign, split the roles at the account-structure level: a separate Search campaign for the brand only, PMax with a new-customer goal and exclusions enabled, and a hard rule that you judge each layer on a different metric. This structure works for most e-commerce accounts because it doesn't leave the automation to decide who gets credit for the easiest conversions.

• A separate branded Search campaign (exact and phrase match on the brand name) with its own protected budget. That campaign handles branded traffic.
• Performance Max with the "new customer acquisition" goal and brand exclusions enabled, measured solely on customers you didn't have before.
• Search campaigns on generic (non-branded) high-intent queries that you deliberately don't want to hand to the automation.
• One shared dashboard where you see the cost and revenue of each layer separately. Without it you'll again see a single averaged, inflated ROAS.

FAQ: Performance Max and ROAS