Ad Fraud in Digital Advertising: Types Marketers Should Know

 Digital advertising in Europe is projected to reach around €142B in 2026. Yet a portion of that investment never reaches real audiences.

Recent industry measurements highlight the scale of the issue:

• ~7–8% of ad traffic in Europe is estimated to be invalid

• ~20% of global ad traffic shows fraud risk signals

• 20–30% of digital ad spend may be exposed to fraudulent activity

• Ad fraud is estimated to cost advertisers €35B–€40B globally each year

So what does ad fraud actually look like in practice? Below are some of the most common tactics used across digital advertising.

Why It Matters

Ad fraud does more than waste budget. It distorts performance data, undermines trust in the ad ecosystem, and makes campaign optimization harder.

As digital advertising becomes more automated and programmatic, fraud tactics continue to evolve. Marketers and advertisers need stronger verification tools, supply chain transparency, and fraud detection systems to ensure their campaigns reach real audiences.

Understanding these common fraud types is a key first step toward protecting ad spend and improving campaign accountability.