Performance Max for E-Commerce: The Truth Nobody Tells You

The Performance Max campaign shows a ROAS everyone is happy with, so nobody touches it. Then someone opens the search terms, sees the brand name sitting at the top of the list, and turns on brand exclusions. Two weeks later the ROAS is a lot lower, total revenue has barely moved, and the meeting gets awkward. The campaign did not get worse. It just stopped taking credit for sales you were getting anyway.

Short version: Performance Max for e-commerce can be the biggest revenue driver in a product account, but by default it mixes brand demand, Shopping, video and Display into one blended number that flatters it. Turn on brand exclusions, read the channel and search terms reports, set targets from your margin, give it proper assets and a clean feed, and judge it on total account growth rather than its own ROAS.

If you suspect your PMax is underperforming but cannot prove it, book a free audit call here and we will pull the channel and brand breakdown with you. Otherwise, here is what is really going on inside Performance Max for e-commerce stores.

What Performance Max for e-commerce actually is

Performance Max is a goal-based campaign that serves across Google's inventory from a single campaign: Search, Shopping, Display, YouTube, Gmail, Discover and Maps. For a store with a Merchant Center feed, it reads your products, your creative assets and your conversion data, and decides where to show which ad, to whom, at what bid.

Google pitches it as one campaign to replace many. For e-commerce, the honest description is narrower. In many feed-led accounts, Performance Max behaves mostly like an automated Shopping campaign with video and Display attached, and how much spend goes where depends on your feed, your assets and your settings. The only way to know for your account is to look, and Google now gives you the reports to do that.

What Google tells you vs what actually happens

None of this makes PMax bad. It makes it a tool that rewards an advertiser who checks its work. You cannot set a fixed channel split, so the levers you do have, brand exclusions, negatives, assets, feed and targets, matter more than they would in a campaign you steer by hand.

The blended ROAS problem in Performance Max for e-commerce

The blended ROAS number is where most brands get fooled. It looks great, and it can still hide money being lost.

Here is how it plays out. A PMax campaign reports a healthy blended ROAS. Then you open the channel performance report and Shopping placements are carrying the whole result while some video or Display spend sits well below break-even. Shopping subsidises the weaker channels and the blend looks acceptable.

That is arithmetic, not a client result, but the shape is common enough that you should check your own account for it. The fix is rarely to switch PMax off. It is to see the split, decide whether the weaker channels are doing a job you value, and adjust assets, targets and structure accordingly.

How to read the channel performance report

Google added channel-level reporting to Performance Max in 2025. Open the campaign, find the channel performance view, and compare spend, conversions and conversion value by channel over at least 30 days. Look for channels with meaningful spend and very little value. Then compare the same period last year rather than last month, because seasonality can make any channel look strange over a short window.

How PMax takes credit from your brand campaign

This is the biggest issue with Performance Max for e-commerce. When someone searches your brand name, someone who was going to buy from you anyway, PMax can show them a Shopping ad. They click, they buy, and PMax reports it as a PMax conversion. You paid for a click from a customer who was already on their way to you. That is not growth.

The three-check test

1. Check brand Search before and after PMax launched. Did brand Search impressions or impression share drop when PMax started?
2. Read the PMax search terms report. Performance Max now has a search terms report. Total the conversions coming from brand queries.
3. Look at total account conversions. Did conversions across the whole account rise, or did they just move from Search to PMax?

If brand queries account for a large share of PMax conversions and the account total did not grow, PMax is taking credit for sales your brand campaign would have captured, usually at a lower cost per click.

Brand exclusions: the fastest honest fix

For Performance Max for e-commerce accounts, brand exclusions are the first setting to check. Performance Max supports them natively. Create a brand list with your brand name (Google suggests matching brands, and you can request one if yours is not listed), then apply it in the campaign settings under Brand exclusions. By default the exclusion applies to both Search and Shopping inventory, with an option to let Shopping ads still appear on searches for excluded brands if you prefer to keep those.

Expect the reported PMax ROAS to fall. You just removed the easiest, highest-converting traffic. What remains is the non-brand performance, which is the number that measures growth. Give the campaign two weeks to settle. If non-brand ROAS is still above your profit threshold, good. If it is below, you now know the campaign was being propped up by brand traffic, which is painful but far better to know.

Negative keywords and search terms inside PMax

For years, PMax gave almost no keyword control. That has changed. Performance Max now supports campaign-level negative keywords, with the limit raised to 10,000 per campaign in 2025, plus shared negative keyword lists and account-level negatives. They apply to PMax's Search and Shopping inventory. Read the PMax search terms the same way you read Standard Shopping ones, and add negatives for clear waste: job seekers, DIY, free, products you do not stock. Our guide on how to add negative keywords covers match types and levels.

Use negatives for waste and brand exclusions for your own brand. Do not try to exclude your brand with negative keywords in PMax; the brand exclusion setting is built for that job.

Performance Max for e-commerce vs Standard Shopping: the priority change

Performance Max used to win automatically over Standard Shopping when both campaigns covered the same product. Google changed this in late 2024. Where products overlap, normal auction rules apply and the campaign with the higher Ad Rank serves. That makes running both campaign types side by side more predictable than it used to be.

The combination that works for many stores

Standard Shopping for products where you want control. Best sellers, hero products, or anything where you want to see search terms, set bids directly and protect a budget.

Performance Max for discovery and the long tail. PMax is good at finding customers for products without enough individual data for manual Shopping to optimise. Let it work the parts of the catalogue you would not target by hand.

This gives you control where it matters most and lets PMax do what it does well. Our full comparison of PMax vs Shopping vs Demand Gen walks through when each campaign type fits.

The right way to structure Performance Max for e-commerce

Most brands create one PMax campaign with one asset group and put every product in it. That is the "one Shopping campaign for everything" mistake, made worse, because PMax also controls your video and Display presence.

Split by margin and price, not just category

Group products so that margin and price point are similar inside a campaign. A single ROAS target cannot be right for a low-margin accessory and a high-margin hero product at the same time. Campaigns built around margin bands let each one carry a target that matches its economics. Our guide to break-even ROAS shows how to work out those targets.

Asset groups that actually work

Inside a campaign, build separate asset groups for each major product category, with:

• Category-specific listing groups so each asset group serves the right products.
• Category-specific creative: lifestyle images of that category, not generic brand shots.
• Category-specific headlines and descriptions, not "Shop Our Collection" copy that says nothing.
• Category-specific audience signals: custom segments built from relevant searches and competitor sites for that category.

Audience signals do not restrict who sees your ads; PMax can show ads to anyone it predicts will convert. Signals tell the system where to start looking.

Customer acquisition settings

Performance Max has a customer acquisition goal that can bid higher for new customers or, in some setups, target new customers only. If growth means new customers, this setting deserves attention, but it needs a reliable way for Google to tell new from returning customers, such as customer lists or your conversion data.

Creative assets: do not give Google an excuse

If you only upload product images, Google fills the gaps. For video, it can generate videos from your images and text, and those rarely look like anything a brand would choose. PMax will still spend money showing them.

• Several landscape and square images: lifestyle shots, not only product on white.
• At least one real video, even a simple product showcase, so Google is not building one for you.
• 15 headlines and 5 descriptions, all filled. Benefit-led copy gives the system better raw material.
• A clean product feed, because for Performance Max for e-commerce the feed is the biggest single asset. Titles, images and attributes decide which searches your products can match.

Performance Max for e-commerce: settings worth checking

How to evaluate Performance Max for e-commerce honestly

1. Total account performance first. Did overall revenue and profit improve after PMax launched, or did conversions shift from other campaigns?
2. New customer share. If PMax mostly converts existing customers and brand searchers, it is not doing the job you are paying for.
3. Non-brand PMax ROAS vs Standard Shopping ROAS. They should be in the same range. If PMax non-brand is far lower, the campaign is struggling.
4. Channel and placement quality. Read the channel report and the placement data. If your premium product ads are running on games for children, intervene.
5. Against break-even, not a target someone liked. Compare results to the ROAS your margin needs.

If the campaign is spending but not converting at all, the issue is usually upstream of these checks. Work through why Performance Max is not converting in order, starting with tracking and feed.

The bottom line on Performance Max for e-commerce

PMax is a powerful tool when you know what it is doing. It is not a replacement for a thought-through account. The stores getting real results use brand exclusions from day one, read the channel and search terms reports, keep Standard Shopping where they need control, build asset groups around margin and category, and judge PMax on incremental contribution, not blended ROAS.

The stores that hand everything to PMax and hope tend to be the ones paying for their own brand demand. Whatever the budget, the fix follows the same pattern: exclude brand, check the channel split, protect top products, set honest targets. Request a free audit or book a free PMax audit call and we will show you what your PMax is hiding.

Frequently asked questions

Is Performance Max good for e-commerce?

Yes, when it is structured and checked, and expensive when it is left alone. Performance Max for e-commerce works best with brand exclusions, a clean feed and margin-based targets. PMax can be the largest revenue driver in a product account, but by default it can take credit for brand searches you would have won anyway and spend in channels you never look at. The difference between the two outcomes is setup and monitoring.

Does Performance Max take credit for branded sales?

It can. Without brand exclusions, PMax can serve on searches for your own brand and report those sales as its own performance, which inflates its ROAS and hides how it performs with new customers. Brand exclusions, with a brand Search campaign alongside, are the most clarifying change you can make.

Does Performance Max still take priority over Standard Shopping?

No. Since Google's change in late 2024, where PMax and Standard Shopping cover the same product, the campaign with the higher Ad Rank serves. PMax no longer wins automatically.

Can I add negative keywords to Performance Max?

Yes. PMax supports campaign-level negative keywords, with up to 10,000 per campaign, as well as shared negative keyword lists and account-level negatives. They apply to its Search and Shopping inventory. Use brand exclusions, not negatives, for your own brand.

How should Performance Max be structured for a store?

Not as one campaign for the whole catalogue. Group products so margin and price are similar within each campaign, build category asset groups with real creative and audience signals, keep a clean feed, and run Standard Shopping where you want direct control.

How do I know if my PMax is actually performing?

Judge it with brand traffic excluded and against your break-even ROAS. Read the channel performance report, compare total account revenue before and after changes, and be suspicious of a ROAS that looks too good, because it often contains your brand demand.