Performance Max has always been a bit of a black box. You give it conversion goals and some inputs, and it goes off to find more of whatever appears to be working. The issue in B2B is that "whatever works" can include a lot of people you don't actually want.
That's partly because PMax was built for consumer marketers with broad audiences and lots of conversion data. If your TAM is 10,000 accounts and your monthly conversions are in the dozens, you're not feeding the algorithm enough signal to do anything useful on its own. And if you optimize for form submissions, PMax will happily keep finding more people willing to submit the form, whether or not they're actually qualified. Audience exclusions give B2B marketers a way to control that.
What exclusion audiences change
With exclusions, you can suppress specific segments from a PMax campaign. That means you can put some basic guardrails around where PMax spends and what it learns from.
Google's built-in audiences, like affinities and interests, might clean things up a bit, but they probably aren't going to dramatically improve lead quality on their own. The bigger opportunity is bringing in a suppression audience built around who your business already knows is a bad fit.
Build a large Anti-ICP audience
With Primer, you can build an audience of up to roughly 50M people that represents your Anti-ICP: the people you never want to serve an ad to. That can include every bad-fit title, every existing customer, and every disqualified lead. You then sync that audience to Google, use it as an exclusion in PMax, and let the algorithm spend on what's left.
At that point, you're effectively telling the algorithm:
- don't go here
- don't serve ads to these people
- we know these aren't qualified
That's the game changer.
How to add the exclusion in PMax
The setting lives inside your PMax campaign settings, but it's easy to miss. Click More settings, open Your data exclusions, and check Enable your data exclusions. Then go to the Browse tab, choose Customer lists, select your Primer Anti-ICP audience once it has synced to Google, and click Next to save.
Google supports Customer Match, website visitor lists, and Google Analytics lists for these exclusions. They apply across Search, Display, Shopping, Video, and Discover inventory within the PMax campaign.
Signals and conversion data still matter
Exclusions are only one part of the setup. PMax still needs good signals about your ICP and clean data about what a valuable conversion looks like. That starts with the signals in your asset groups: Primer audiences can be used there to give Google a clearer picture of who you want to reach as it optimizes. The B2B marketer's guide to PMax and Demand Gen covers that setup in more detail.
Conversion data matters just as much. If you're only sending raw form submissions back to Google, the algorithm has limited information about which of those leads actually turned out to be useful. Pushing CRM conversion data back in gives PMax a better signal to optimize toward.
It's the combination that makes PMax work for B2B: large suppression audiences, good signals in your asset groups, and clean conversion data. On its own, PMax is still going to do what it does.
