What you’re running into is one of the most common Performance Max blind spots — Google’s reporting lumps everything together unless you deliberately set it up to differentiate new vs. existing customers.
Right now, without extra configuration, PMax will happily claim conversions from people already in your remarketing lists, so it can look like acquisition is strong when it’s actually recycling leads.
Here’s how to get clarity:
1. Use the New Customer Acquisition (NCA) setting in PMax
In campaign settings, under “Customer Acquisition”, you can tell Google to either:
Bid higher for new customers, or
Only bid for new customers (true acquisition mode).
You’ll need to upload a Customer Match list of all known customers (emails, phone numbers) so Google can exclude them from acquisition reporting.
This doesn’t guarantee perfection, but it improves attribution accuracy dramatically.
2. Compare PMax “New Customers” column vs. total conversions
In Google Ads, add the New customers and New customer value columns.
If you see a high gap between total conversions and new customers, you know PMax is leaning heavily on remarketing.
3. Cross-check with GA4’s first-time visitor metrics
In GA4, look at First-time Purchasers or First Visit conversions tied to your PMax traffic.
Break down by Session source/medium and isolate your Google Ads campaigns.
If the share of first-time visitors is low, you’re mostly hitting existing audiences.
4. Segment in your CRM
Tag incoming leads from PMax by UTM parameters.
Match them against your CRM to see if they’re already in your database.
If you’re seeing a large overlap, you’ll know remarketing is inflating PMax’s acquisition numbers.
5. Tighten audience exclusions
In Audience exclusions, add:
All converters from the past X days (lookback window depends on your sales cycle).
Your existing Customer Match lists.
Engaged website visitors from remarketing lists if you want purely net-new reach.
6. Watch the overlap between PMax and remarketing campaigns
If you’re also running Display/Discovery remarketing, PMax can cannibalize those audiences since it has cross-channel reach.
Use account-level audience exclusions to force PMax into cold prospecting.
Pro tip:
If you want proof that PMax can’t pad its numbers with old users, run a short test:
Duplicate the campaign
Switch the duplicate to “Only bid for new customers”
Run it for 2–4 weeks
Compare CPA and volume with your current setup.
That’ll give you a clean read on true acquisition performance.