If you’re running an e-commerce store and using Google Ads (especially Performance Max / Shopping), you need to know about zombie SKUs. These are products in your catalog that Google barely (or never) shows in ads. They’re on the books, but not alive in your campaigns.
In fact, we view them as “the biggest obstacle for e-commerce businesses trying to scale with Google Ads.” This is one of the most common issues we see when auditing accounts built by non advanced Google Ads Agencies.
What Exactly Is a Zombie SKU?
- A Zombie SKU is a product that exists in your feed (Performance Max, Shopping, etc.) but receives zero clicks, or sometimes zero impressions, over a period of time. It’s “on,” but Google doesn’t show it.
- Most definitions use a time window (30 days, 60 days, etc.) and include a filter like impressions = 0 or cost = 0.
- It’s not necessarily a bad product. It might just be neglected by the algorithm in favor of “safe bets.”
Why this matters: if Google never gives a product a chance, you never know if it could’ve been a winner.
Why Do Zombie SKUs Happen?
Before you go yanking products out into their own campaign, you need to understand why they ended up zombies. Otherwise you’ll just be rearranging deck chairs.
Algorithm Bias & Data Volume
Modern campaigns (like Performance Max) lean into what’s already performing. They focus spend on products that have historical data, clicks, conversions. The algorithm “plays safe.” That means low-visibility SKUs can get pushed aside. This is why campaign structure and segmentation matter more than most people realize.
Poor Feed / Listing Quality
Some SKUs are excluded because they violate feed rules (disapproved in Merchant Center), have mismatched pricing, bad landing pages, missing images, or poor titles/descriptions. If Google sees errors, those products might never be eligible for auctions.
High ROAS / CPA Targets & Smart Bidding Constraints
If your account uses aggressive smart bidding (tROAS, maximize conversion value) the algorithm has less leeway to test lower-performing inventory. If a SKU doesn’t immediately meet its margins, it might get throttled. This is exactly how the system is supposed to optimize.
Reporting Bias & Selection Bias
The reporting in Google Ads is tricky. Clicks and conversions get attributed to the ad/product that was clicked—even if the user later buys another SKU. So some SKUs look like “zombies” when in reality they get credit for sales through cross-navigation. Also, just because a product didn’t get clicks over one period doesn’t mean it never will. Some SKUs are in the long tail—they oscillate. If you pick your “zombies” poorly, you’ll catch SKUs that would’ve revived themselves.
The “Zombie SKU PMax Campaign” Idea
Here’s how the zombie SKU strategy is usually pitched:
- Filter all SKUs with zero clicks or zero spend over a time window.
- Label them (via custom label / supplemental feed).
- Exclude them from your main PMax / Shopping campaigns.
- Launch a new campaign (often Performance Max) that only contains those “zombie SKUs.”
- Use looser targets, more aggressive bidding, or removal of strict ROAS constraints to let them get a fair shot.
- After a while, bring the winners back into the main campaigns.