By Jan Wolfe and Patience Haggin

Alphabet's Google created an illegal monopoly that allowed it to control parts of the online advertising industry, a federal judge ruled Thursday, a decision that could upend one of the technology giant's core business.

The ruling marked the second time in eight months that a U.S., judge labeled Google an illegal monopolist -- and could lead the Justice Department to seek a forced sale of some of the company's advertising products.

Google shares fell 1.5% in Thursday morning trading.

U.S. District Judge Leonie Brinkema said Google's monopoly in ad exchanges and server markets violated the Sherman Antitrust Act, harming advertisers and consumers.

Brinkema, who sits in Alexandria, Va., said in her written ruling that the company also engaged in unlawful "tying" -- conditioning access to one product on paying for the other.

In August, U.S. District Judge Amit Mehta of Washington, D.C., ruled that Google's dominant search engine is an unlawful monopoly.

Google says it competes fairly, and that the Justice Department's case is premised on an outdated view of the digital ads market. Google is expected to appeal Brinkema's ruling, as well as the earlier one by Mehta. Those appeals could take years.

The company still faces stiff headwinds in Washington. Republican appointees now control the Justice Department and Federal Trade Commission and have signaled a desire to continue tough enforcement against Big Tech.

In the coming months, Brinkema and Mehta will hear arguments about how to remedy Google's conduct.

The Justice Department has previously said competition can be restored by forcing Google to sell parts of its ad-tech business, which generated $31 billion in revenue last year -- or about a tenth of the company's overall sales. In the search case, the Justice Department has proposed Google sell its popular Chrome browser.

Write to Jan Wolfe at jan.wolfe@wsj.com and Patience Haggin at patience.haggin@wsj.com

(END) Dow Jones Newswires

April 17, 2025 11:50 ET (15:50 GMT)

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