Alexandria, Virginia | The US Department of Justice accused Google of running an ad tech monopoly that cut off potential rivals and drove up costs for publishers and advertisers in an attempt to maximise profits, as the latest antitrust trial against big tech got under way on Monday (Tuesday AEST).

Google used its acquisition of advertising software company DoubleClick in 2008 to dominate technology that auctions off ads on webpages as users visit, Julia Tarver Wood, the government’s lead trial lawyer, said in opening statements.