The U.S. Justice Department told a federal judge Alphabet's Google illegally dominated online advertising technology in seeking a second antitrust win against the company.

Judge will decide whether the internet giant, already facing the prospect of a breakup over its monopolistic search engine, also runs its advertising unit as an illegal monopoly.

A federal judge will hear arguments on whether Google's advertising tech constitutes a monopoly as closing arguments begin Monday.

Late Wednesday, Google filed its appeal of the Epic v. Google antitrust, asking a federal appeals court to throw out the ruling.

Canada's antitrust watchdog is suing Google over its anti-competitive conduct in its adtech business, the country's Competition Bureau said Thursday. The Competition Bureau, Canada's independent law enforcement agency responsible for regulating anti-competitive conduct,

Canada's Competition Bureau says that an investigation found the company "unlawfully" tied together its ad tech tools to maintain its dominant market position.

Canada's antitrust watchdog is suing Google to force the breakup of the company’s ad tech unit. In a statement published Thursday, during the US Thanksgiving holiday, the Competition Bureau said a “thorough” investigation had found that Google had abused its dominant position in programmatic web advertising to “maintain and entrench its market power.

In its case targeting how Google buys and sells online advertising in Canada, the Competition Bureau says the company "has abused its dominant position." But those who study the tech giant say reducing its market influence won't be easy.

KEY TAKEAWAYS Canada's antitrust regulator is suing Alphabet's Google over alleged anti-competitive conduct in its online-advertising business, in the latest regulatory challenge to the tech giant's dominance.