Justice Dept. Is Said to Accelerate Google Advertising Inquiry

WASHINGTON — The Department of Justice has accelerated an investigation into Google’s digital advertising practices and may file an antitrust lawsuit against the internet giant before the end of the year, two people with knowledge of the government’s thinking said on Wednesday.

The investigation focuses on Google’s power in the digital ad market, looking at how the company uses its dominance in auctions and ad technology to maintain its power, said the people, who were not authorized to speak publicly. In recent weeks, the Justice Department has called in more third parties as witnesses and asked for documents and interviews, in a sign it has picked up the investigation’s pace, the people said.

The department declined to comment. Google said on Wednesday that there was “enormous competition in advertising tools, which has made online ads more relevant, reduced fees, and expanded options for publishers and advertisers.”

Bloomberg earlier reported on the potential lawsuit.

If the Justice Department pursues the lawsuit, it will be the federal government’s second against Google. In federal court in October, the department filed an antitrust lawsuit alleging that Google abused its monopoly in internet search to harm rivals and consumers.

A second lawsuit would also be a show of force by the Biden administration to rein in the power of big tech companies. President Biden has appointed critics of Amazon, Apple, Facebook and Google into the top antitrust positions in government. In July, he named Jonathan Kanter, who represented Google’s rivals Yelp and Microsoft, to lead the Justice Department’s antitrust division. Mr. Kanter’s nomination requires Senate confirmation.

Mr. Biden’s antitrust appointees have picked up from decisions made during the Trump administration to bring landmark antitrust suits against tech giants. Apart from the suit against Google over search, the Federal Trade Commission sued Facebook last year, accusing it of abusing its power over social networking. After a judge threw out the case, the F.T.C. has refiled it.

With Google, the Justice Department focused first on search but was also investigating whether the company abused its dominance in digital advertising. Dozens of media companies, advertisers and ad technology companies have claimed Google’s ad practices are anticompetitive. Google operates various parts of digital advertising auctions, including the purchase of ads for marketers and the selling of ad space by publishers.

The agency is looking into allegations that Google and Facebook entered into an illegal agreement to manipulate the online auctions, the people with knowledge of the situation said.

Texas has led a lawsuit by several state attorneys general accusing Google of abusing competition in advertising technology. It was unclear if the Department of Justice would join the states in their complaint.