Alphabet Inc (NASDAQ:GOOG) shares fell 1.5% on Thursday after a US federal judge ruled that Google unlawfully maintained monopoly power in its digital advertising business.
The ruling by Judge Leonie Brinkema found that Google violated antitrust laws by tying together its ad server and ad exchange technologies, enabling it to dominate the $31 billion market for matching advertisers with website publishers.
According to the judge, the company’s conduct harmed competition, publishers, and ultimately consumers.
The decision marks the second significant antitrust victory for the US government against Google in under a year and follows a separate ruling that the company’s app store was also an illegal monopoly. Combined, the rulings highlight mounting legal challenges to Google’s business practices.
While the judge rejected one of the government’s claims concerning advertiser tools, she agreed that Google's practices in the publisher ad market crossed legal lines. The ruling raises the possibility that Google may be forced to divest parts of its advertising business, though appeals could take years.
Google said it would appeal the decision on its publisher tools.
“We won half of this case,” said Lee-Anne Mulholland, Google’s vice president of regulatory affairs, maintaining that its tools are competitive and beneficial for publishers.