Performance Max Not Working? Here's Why (And What to Do About It)

Google positions PMax as an all-in-one campaign that uses AI to find the best customers across every Google channel. That sounds great in theory.

In practice, PMax is a black box that distributes your budget across Search, Shopping, Display, YouTube, Gmail, Discover, and Maps — and gives you minimal control over how much goes where or what queries trigger your ads.

For e-commerce businesses with product feeds, PMax can genuinely work well because Shopping ads are a natural fit. For lead generation businesses (services, B2B, professional services), PMax often underperforms because:

• A large portion of budget goes to Display and YouTube — cheap impressions that rarely generate qualified leads
• You can't see or control which search queries trigger your ads
• You can't exclude low-performing placements the way you can with standard Display campaigns
• The campaign automatically bids on your brand name, inflating conversion numbers with traffic you'd get anyway

For a complete understanding of how PMax works and when it makes sense, read our Performance Max guide.

This is the biggest issue with PMax that most businesses don't realise. Performance Max takes priority over standard Search campaigns for query matching. This means when someone searches your brand name, PMax serves the ad instead of your branded Search campaign.

Why does this matter? Because branded traffic converts at 10-20x the rate of non-branded traffic. When PMax claims those conversions, it makes the campaign's overall performance look much better than it actually is. Your PMax might show a £30 cost per lead, but if you strip out branded conversions, the non-branded CPL could be £150+.

How to check: Go to your PMax campaign → Insights → Search term insights. Look at the categories. If “branded” or your company name appears as a significant category, PMax is cannibalising your brand traffic.

How to fix: Add your brand name and variations as negative keywords at the account level (you can now do this for PMax). This forces branded traffic back to your standard branded Search campaign where it belongs.

With standard Search campaigns, you can see exactly which keywords are triggering your ads, what you're paying per click, and which landing pages are converting. With PMax, this visibility is severely limited.

You get “search term insights” (categories, not individual queries), “placement reports” (limited detail), and “asset performance” (basic ratings). You can't see your actual cost per click on Search vs Display vs YouTube. You can't identify and block individual irrelevant search terms. You can't exclude specific websites or apps where your ads are showing.

For businesses that need to account for every pound of ad spend, this lack of transparency is a dealbreaker. You're essentially trusting Google to spend your money well — and as we've covered in our guide on Google rep recommendations, Google's incentives don't always align with yours.

If you're going to run PMax, avoid these common mistakes:

• Too few assets. PMax needs at least 5 headlines, 5 descriptions, 5 images, and 1 video to perform well. Fewer assets means fewer combinations for Google to test.
• No audience signals. Don't leave audience signals blank. Add your customer lists, website visitors, and in-market audiences. These aren't targeting restrictions — they're starting points that help Google's algorithm learn faster.
• One asset group for everything. Create separate asset groups for different product/service categories with tailored assets and audience signals for each.
• No brand exclusions. As discussed above, exclude your brand name to get an accurate picture of non-branded performance.
• Running PMax alongside standard Search without understanding priority. PMax takes priority for query matching. If you run both, PMax will cannibalise your Search campaigns.

Keep PMax if:

• You're e-commerce with a product feed (Shopping ads through PMax work well)
• You've excluded brand traffic and non-branded CPL is acceptable
• You have 50+ conversions/month giving the algorithm enough data
• You're comfortable with limited visibility in exchange for convenience

Replace PMax with standard Search if:

• You're a lead generation business and CPL has increased since launching PMax
• You need to see and control exactly which keywords your ads appear for
• Your conversion volume is below 30/month (not enough data for PMax's algorithm)
• You need to justify every pound of spend to clients or management