Brands worldwide are set to lose $6.5 billion in online advertising spend to fraudulent bots this year, according to recent research from White Ops and the Association of National Advertisers (ANA).

The report was based on an analysis conducted by White Ops in 4Q16 of the online advertising spend of 49 ANA member companies, including major corporations, such as Coca-Cola, American Express, and Target. Global estimates were determined in part based on the amount of fraud seen with the sample advertisers.

The researchers examined only digital display and video ad buys—not search buys, pay-per-click (PPC) buys, or paid social media campaigns.

Total projected online ad spend loss to bot traffic (impressions from nonhumans) is down 10% from 2017. The researchers theorize the decline is due to the increasingly sophisticated strategies brands are deploying to fight fraud.