OpenX Files Antitrust Lawsuit Against Google Over Adtech Monopoly

OpenX, a supply-side advertising platform, has filed an 88-page antitrust lawsuit against Google in the U.S. District Court for the Eastern District of Virginia, accusing the tech giant of leveraging its dominant market position to suppress competition and harm rival businesses in the digital advertising space. The lawsuit alleges that Google employed self-preferencing tactics such as requiring publishers to use its DoubleClick ad server to access its ad exchange, restricting access to Google Ads through its own exchange, and manipulating auction mechanics to view competing bids and adjust its own in real time, effectively rigging auctions to favor its ad exchange. OpenX claims these practices stifled innovation, decreased product quality, and caused significant damage not only to OpenX but also to publishers and advertisers. The suit follows a landmark April 2025 ruling by Judge Leonie Brinkema that found Google unlawfully monopolized certain ad tech markets, including publisher ad servers and ad exchanges, and suggested the possibility of splitting up Google's ad business. OpenX emphasizes that Google's conduct forced its ad server business to shut down in 2019 and severely hurt its ad exchange operations, with Google’s strategy described internally as a conflict of interest akin to a major bank owning the stock exchange. OpenX seeks substantial damages for these anticompetitive practices, which they say have undermined fair competition and innovation across the digital advertising industry.