US Seeks to Break Up Google's Advertising Business

The US government has applied to a federal judge seeking an order to dismantle Google’s digital advertising business. Government lawyers argue that the tech giant’s promises to reform its business practices cannot be trusted.

The application was submitted to the federal judge on Friday (21 November).

In a case concerning Google’s ad tech stack—which includes the tools enabling website publishers to sell ads and advertisers to purchase them—government lawyers presented their final arguments.

This marks the second major antitrust test for Google this year.

Earlier in September, a judge from the Department of Justice (DOJ) dismissed a similar request aimed at breaking up the California-based tech giant’s global search engine business.

These cases form part of the US government’s broader effort to curb the monopolistic power of major tech companies, including Apple, Amazon and Meta.

The outcomes so far have been mixed. Earlier this week, another judge dismissed the government’s case against Meta’s social media empire.

In a document filed before Friday’s closing arguments, the DOJ and several US states alleged that Google had unlawfully monopolised two interconnected markets for advertising technology.

They claimed that Google had engaged in various illegal practices for over a decade.

The government’s case asserts that Google simultaneously controls multiple segments of the advertising market—publisher ad platforms, transaction exchanges, and the demand from a vast number of advertisers.

The DOJ noted that Google once compared this system to Goldman Sachs owning the New York Stock Exchange.

Assistant Attorney General Gill Slater wrote in a post on X: ‘We are here to fix the problem. We will argue that dismantling Google’s monopoly is the best solution. It will create new competitors.’

Google countered that the proposed measures would amount to extreme government intervention, harming publishers, advertisers and consumers. The company argued that its integrated advertising tools enhance efficiency and innovation, and that dismantling them would be technologically near-impossible.

In an earlier preliminary ruling on liability, federal judge Leonie Brinkema said Google had intentionally monopolised both the publisher ad server and ad exchange markets. This paved the way for the final arguments.

Prosecutors are now seeking sweeping actions, including forcing Google to sell its AdX exchange and making key auction technology open-source.

According to Laurel Kilgore of the American Economic Liberties Project, Judge Brinkema expressed concern that her decision might later be overturned. Google is almost certain to appeal, meaning the process could continue for years.

The 11-day trial included testimony from 19 witnesses and seven experts.

In the search engine case, the judge had noted that the rise of artificial intelligence (AI) was a reason to be cautious about imposing harsh measures against Google.

However, in the ad tech case, DOJ lawyers argued the opposite—claiming that advances in AI would further entrench Google’s dominance rather than challenge it. A final ruling is expected within the next few months.