A federal U.S. judge ruled Monday that Google has illegally held a monopoly in two market areas: search and text advertising.

The landmark case from the government, filed in 2020, alleged that Google has kept its share of the general search market by creating strong barriers to entry and a feedback loop that sustained its dominance. The court found that Google violated Section 2 of the Sherman Act, which outlaws monopolies.

The ruling marks the first anti-monopoly decision against a tech company in decades.

“Google is a monopolist, and it has acted as one to maintain its monopoly,” Judge Amit Mehta of the U.S. District Court for the District of Columbia wrote in the decision.

Google CEO Sundar Pichai in 2023.Boris Streubel / Getty Images for DFB

The Department of Justice and a bipartisan group of attorneys general from 38 states and territories, led by Colorado and Nebraska, filed similar but separate antitrust suits against Google in 2020. The suits were combined for pretrial purposes, such as discovery of evidence.

Attorney General Merrick Garland called the decision a “historic win for the American people.”

“No company — no matter how large or influential — is above the law,” Garland wrote in a statement. “The Justice Department will continue to vigorously enforce our antitrust laws.”

In its ruling, the court homed in on Google’s exclusive search arrangements on Android and Apple’s iPhone and iPad devices, saying that they helped to cement Google’s anticompetitive behavior and dominance over the search markets.

General search services, according to the court, applies to Google’s core search engine, where it traditionally competed with Yahoo. General search text advertising refers to the text ads that run alongside search results. The court ruled that in both of those areas, Google has operated as a monopoly. However, the ruling found that general search advertising is not a market so there can be no monopoly control.

Kent Walker, Google’s president of global affairs, said in a statement that the company plans to appeal the ruling. He highlighted the court’s emphasis on the quality of Google’s products.

“This decision recognizes that Google offers the best search engine, but concludes that we shouldn’t be allowed to make it easily available,” Walker wrote. “As this process continues, we will remain focused on making products that people find helpful and easy to use.”

Alphabet shares fell more than 4% on Monday, dragged down by a broad decline in stocks worldwide.