Performance Max is Google's flagship campaign type. It's also the single biggest budget leak we see in client audits.
This isn't because PMax is bad. It's because the default setup that Google's own reps recommend is optimized for Google's revenue, not yours. Most advertisers who launch PMax see a "lift" in conversions, but when you dig into the data, you find PMax stole credit from Search campaigns that would have converted anyway.
Here's what's actually happening, and the 5 specific configurations we change in every PMax campaign we audit.
What PMax actually does
Performance Max isn't a search campaign. It's not a display campaign. It's not a YouTube campaign. It's all of those at once, with Google's algorithm choosing where to spend your money in real time.
That sounds great. Here's the catch:
When Google has access to all of these surfaces simultaneously, it has a strong incentive to bid on the cheapest, lowest-quality inventory available, because that's what maximizes ad impressions for any given budget. The lowest-quality inventory is rarely the most profitable for you.
This isn't a conspiracy. It's just incentives. Google's bidding algorithm optimizes for "conversions within the budget you've set." But if conversions are easier to find on display + remarketing + YouTube than on Search, that's where your money goes, even if those conversions would have happened anyway.
Leak #1: PMax cannibalizes your Search campaigns
This is the biggest one.
Picture this: you have a Search campaign targeting "google ads agency" with a $30 max CPC. You ALSO launch a PMax campaign because Google's rep recommended it. The PMax campaign also bids on "google ads agency", but at $48 CPCs because PMax has access to broader audience signals.
Result: PMax wins the auction. Your Search campaign reports declining performance. You "fix" it by cutting Search spend. PMax is now your only campaign capturing this query, at higher CPCs than your Search campaign was paying.
You've effectively given Google a 60% raise on the same query.
Fix: Add your existing high-performing Search keywords as brand exclusions in PMax (Settings → Brand exclusions). This is buried, Google doesn't surface it during setup because it reduces PMax spend. But it's the single highest-ROI change we make in every audit.
Leak #2: No audience signals = pure guessing
When you launch PMax without audience signals, you're telling Google: "Find conversions among everyone, anywhere, however you want."
PMax then leans heavily on Display + Discovery for cheap impressions. You get conversions, sure, but they're often spam form-fills, accidental clicks, or remarketing impressions to people who would have come back anyway.
Fix: Always add Audience Signals (not Audience Targeting, those are different). Use:
- Customer Match lists (your actual customers)
- Website visitors who completed a high-intent action
- In-market audiences specific to your business
- Detailed demographics that match your ICP
These don't restrict who sees your ads. They give Google's algorithm a "starting point" so it doesn't have to learn from scratch.
Leak #3: No campaign-level negative keywords
Until late 2024, PMax didn't allow negative keywords at the campaign level. Google added the feature after relentless agency complaints.
Most accounts we audit haven't taken advantage of it.
Fix: Email your Google rep and ask them to enable campaign-level negative keywords for your PMax campaigns (it's still gated for many accounts). Then add the obvious wastes: brand terms that should go to your brand campaign, "free", "tutorial", competitor names, irrelevant geographies.
This is one of the highest-leverage hours of work in any account audit.
Leak #4: Asset Group structure with one giant catch-all
The default PMax setup creates one massive asset group with all your products/services jumbled together. This forces Smart Bidding to optimize across very different conversion goals.
If you sell both $50 t-shirts and $5,000 enterprise software, the algorithm can't tell them apart at the asset level. It optimizes for whichever has more volume, usually the cheap product. Your enterprise budget gets siphoned into volume conversions.
Fix: Split asset groups by product line, audience, or value tier. Each asset group gets its own headlines, descriptions, audiences, and creative, but they all share the campaign-level budget and bid strategy. Smart Bidding optimizes within each asset group separately.
Leak #5: No video + image assets = no Display optimization
Counterintuitive, but: if you DON'T provide video and image creative, Google auto-generates them. Auto-generated creative performs worse, which means Google has to spend more impressions to drive the same conversion volume, burning budget faster.
We've audited PMax campaigns where 60% of spend went to YouTube ads using terrible auto-generated 6-second videos. The advertiser didn't even know they were running video ads.
Fix: Either (a) provide professional video/image assets so PMax performs well on those surfaces, or (b) opt out of those surfaces entirely if you don't have brand-quality creative. The setting is in Asset Group → Asset types.
The "PMax Audit Workflow" we run on every account
When we onboard a client running PMax, we do these 5 things in order:
Pull insights report. Look at the Channel breakdown. If Display + YouTube combined exceed 25% of spend without explicit creative for those channels, something's broken.
Add brand exclusions for keywords already protected by Search campaigns.
Audit Asset Group structure. Split if there's only one giant group. Consolidate if there are 8+ underperformers.
Refresh creative. Add 3+ video assets, 5+ images, 15 headlines, 4 descriptions per asset group.
Set audience signals based on customer data.
Average impact: 30-40% reduction in CPC, similar or better conversion volume, materially better lead quality (because the algorithm is no longer scraping bottom-of-funnel impressions).
Should you turn PMax off entirely?
Probably not. PMax is genuinely powerful when configured well, it can find conversions in places your Search campaigns will never reach. The problem is rarely PMax itself; it's the default configuration.
But there are a few accounts where we recommend pausing it:
- B2B SaaS with sales cycles over 90 days (PMax can't optimize against your real conversion event)
- Niche services where Google's audience signals are weak (PMax is just guessing)
- Brands where conversion value matters more than count (PMax averages don't optimize for high-value transactions well)
For most accounts, the answer is configuration, not abandonment.
Want a Performance Max audit?
We do these for free as part of our standard audit. We'll show you exactly which of the 5 leaks is happening in your specific account, with screenshots and a Loom walkthrough.
Whether you work with us or not, you'll know which configurations are leaking budget, and you'll have specific evidence to take to your current agency.