A federal judge ruled Thursday that Google illegally acquired and maintained a monopoly over advertising technology, the second time in less than a year that the tech giant has been found in violation of antitrust laws. 

U.S. District Judge Leonie Brinkema found that Google has a monopoly over two out of three markets in the ad tech space, which helps connect publishers selling ad space online to advertisers.

“Plaintiffs have proven that Google has willfully engaged in a series of anticompetitive acts to acquire and maintain monopoly power in the publisher ad server and ad exchange markets for open-web display advertising,” Brinkema wrote Thursday. 

“For over a decade, Google has tied its publisher ad server and ad exchange together through contractual policies and technological integration, which enabled the company to establish and protect its monopoly power in these two markets,” she continued. 

The ruling is another major blow for Google, after a separate federal judge ruled in August that the company had a monopoly over online search.  

Google is set to head to court next week in the search case to argue against the Department of Justice’s (DOJ) proposal that it be forced to divest from its Chrome browser.