You've probably seen the term "zombie products" in a Google Shopping article or an agency audit report. It sounds dramatic, but it describes something very real: products in your catalog that are technically live but functionally invisible.
What Zombie Products Are
A zombie product is any product in your Google Shopping feed that gets so little impression share it generates no meaningful conversion data.
There's no strict definition. Different agencies use different thresholds. But the pattern is consistent: a product that gets less than 50–100 impressions per month, or no conversions in a 30-day period, effectively doesn't exist to your customers.
That product is still in your catalog. It's still in Google Shopping. But it's invisible. No one's seeing it, no one's clicking it, and no one's buying it.
And you probably have way more of these than you think.
The Scale Nobody Talks About
JumpFly audited over 50 e-commerce accounts and found 54% zombie products. That's more than half.
If you have 3,000 products, 1,620 are likely zombies.
Peter Plesko published data showing that 70–95% of products in typical Google Shopping accounts never enter the "actively considered" set on any given day. Some of that is products that aren't relevant to that search. But a huge chunk is just invisibility due to low performance.
Big Flare found that 59% of products get zero impressions in a typical quarter.
The numbers vary depending on how you measure, but they all point to the same thing: most retailers are running 3,000-product catalogs where only 30–40% of products actually get customer attention.
The rest are zombie products.
Why PMax Creates Zombies By Design
This isn't an accident or a bug in the system.
Performance Max is a machine learning system optimized for efficiency. It looks at thousands of product-auction combinations and learns which ones convert. Then it focuses inventory and budget on the combinations that work.
When a product underperforms, the algorithm reduces its impression share. As impression share drops, it gets fewer clicks. Fewer clicks means less conversion data. No conversion data means the algorithm has even less reason to show it. Eventually, it disappears.
This is the algorithm working as intended. It's optimizing without business context.
To PMax, a zombie product is a success: a product that the algorithm correctly identified as low-performing and stopped wasting budget on. But your business might not agree. PMax has no way to know that the product is strategic to your brand, that it's a new launch needing visibility, that it has higher margins than the products replacing it, or that it builds customer lifetime value even if the immediate ROAS is low.
To the algorithm, those don't exist. There's just ROAS and efficiency.
The Hidden Business Cost
Let's cost this out.
If 1,500 of your 3,000 products are zombies, and you're spending €100k per month on Shopping, your entire budget goes to whatever the algorithm picked as winners. The products it ignored? Some of those are your strategic priorities, your new launches, your high-margin categories. They're in the catalog. They're just not in the game.
The real cost is opportunity. Those 1,500 invisible products might include:
- Premium products with 40% margins (vs 15% on bestsellers)
- New category entries that need market share
- Hero products that create customer loyalty
Instead of appearing in 30% of relevant searches, they appear in 3%. A customer looking for exactly that product finds a cheaper competitor instead.
One retailer I know had a line of sustainable products with 35% margins. Incredible products, strategically important, targeted to build brand perception. They should have been visible. Instead, they were zombies. Budget was flowing to commodity products with 8% margins. Same conversion rate, but half the revenue per conversion.
When we fixed it by allocating budget strategically to the sustainable line, revenue from that category went from 8% of total to 23% in 90 days. Different products got attention. Different results followed.
The cost of zombie products isn't wasted budget. It's strategy that never reaches the market.
What You Can Do About It
The problem isn't PMax. PMax is doing exactly what it's designed to do. The problem is that your business strategy and the algorithm's optimization goals are misaligned, and nobody is bridging that gap.
At Expanly, we built a control layer specifically for this. You define which products matter to your business using business rules: margins, strategic priority, seasonality, new launches. You set allocation targets for each segment. The system makes sure your budget follows your strategy, not just short-term ROAS. PMax still optimizes within each segment, but it does so with the context your business needs it to have.
No manual bid adjustments. No moving products between campaigns. No spreadsheet workarounds that break the next time the algorithm re-optimizes.
If you're curious whether you have a zombie problem (you probably do), we run a free audit that shows exactly how your budget distributes across your catalog. It takes about a week and there's no commitment. Send me a message if you want to see the data.