A US federal judge has rejected the Justice Department's request to force Google to sell off parts of its advertising technology business, opting instead for lighter behavioural remedies after ruling the company had illegally monopolised the ad tech market. Judge Leonie Brinkema said she would largely adopt changes proposed by the parties, though the details remain confidential until redactions are finalised, and mirrors a similar approach taken by another judge in Google's separate search monopoly case. The decision matters because it marks the conclusion of the district court phase in one of the most significant tech antitrust cases in recent US history, with Google avoiding the most severe structural penalty regulators had sought.

The ruling concerned Google's alleged illegal tying of its publisher ad server, DoubleClick for Publishers, to its AdX ad exchange, which the court found made it nearly impossible for customers to switch providers and stifled competition. However, Brinkema found the DOJ had failed to prove Google monopolised the separate market for advertiser-side tools. Likely remedies include restrictions on self-preferencing in ad auctions and requirements for Google to share real-time auction data with rival ad tech firms, though Google may still appeal the underlying monopoly finding, as it has done in its search case. Google welcomed the decision, while the case sits alongside other major US antitrust actions against Meta, Amazon and Apple.