Google has illegal advertising monopoly, judge rules

A US judge has ruled tech giant Google has a monopoly in online advertising technology.

The US Department of Justice, along with 17 US states, sued Google, arguing the tech giant was illegally dominating the technology which determines which adverts should be placed online and where.

This is the second antitrust case Google has lost in a year, after it was ruled the company also had a monopoly on online search.

Google said it would appeal the decision.

"Publishers have many options and they choose Google because our ad tech tools are simple, affordable and effective," the firm's head of regulatory affairs Lee-Ann Mulholland said.

US District Judge Leonie Brinkema said in the ruling Google had "wilfully engaged in a series of anticompetitive acts" which enabled it to "acquire and maintain monopoly power" in the market.

"This exclusionary conduct substantially harmed Google's publisher customers, the competitive process, and, ultimately, consumers of information on the open web," she said.

Google lost on two counts, while a third was dismissed.

"We won half of this case and we will appeal the other half," Ms Mulholland said.

"The Court found that our advertiser tools and our acquisitions, such as DoubleClick, don't harm competition."

Google's lawyer had argued the case focused too much on its past activities, and prosecutors ignored other large ad tech providers such as Amazon.

In an ongoing series of antitrust lawsuits, the US government argues Google and its parent company Alphabet should be broken up - which could include selling off parts of the company such as the Chrome browser.