Ad Stacking

Fraud where multiple ads are layered on top of each other in one slot so several impressions are counted but only one is visible.

By Brandon MinaCEO, BrandPilot AIUpdated November 2026

Short answer

Ad stacking is a form of ad fraud in which multiple ads are layered on top of one another in a single ad slot. Each ad registers an impression, and sometimes a click, yet only the top ad is actually visible to the user, so advertisers pay for exposure that never happened.