Google said it plans to appeal the portion of a judge’s ruling that found its advertising business constitutes an illegal monopoly, while noting that other parts of the ruling had been more favourable.

Last Thursday US District Judge Leonie Brinkema found Google liable for “willfully acquiring and maintaining monopoly power” in markets for publisher ad servers and ad exchanges.

The judge also said Google illegally dominates two markets for online advertising technology.

‘Mixed’ decision

Google said on Friday that the ruling had been a mixed decision, finding that the US Justice Department had failed to show its advertiser tools or its purchases of DoubleClick and AdMeld were anticompetitive, while its publisher tools violated antitrust laws.

The company told Reuters it plans to appeal these “adverse” portions of the ruling.

“We won half of this case and we will appeal the other half,” Google said in a social media post following the ruling.

“We disagree with the Court’s decision regarding our publisher tools.”

Brinkema found that Google had used the influence of its illegal monopoly to raise prices and reduce competition.

The judge said Google’s depriving other companies of the “ability to compete” had substantially harmed users and businesses.

Proposed remedies

“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,” Brinkema wrote.

“Google further entrenched its monopoly power by imposing anticompetitive policies on its customers and eliminating desirable product features.”

The case follows a decision last August by US District Court Judge Amit Mehta that Google’s search business also constituted an illegal monopoly.

The Justice Department has argued that Google must be forced to sell off at least its Google Ad Manager, which includes its publisher ad server and ad exchange.