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.

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.

The lawsuit, filed with the Competition Tribunal, follows a multi-year investigation into Google's dominance in the digital advertising market. According to the Bureau, Google holds a market share of 90 percent in publisher ad servers, 70 percent in advertiser networks, 60 percent in demand-side platforms, and 50 percent in ad exchanges in Canada.