For years, Google has faced complaints about how it dominates the online advertising market.

Many of the concerns stem from the internet giant’s suite of software known as Google Ad Manager, which websites around the world use to sell ads on their sites. The technology conducts split-second auctions to place ads each time a user loads a page.

The dominance of that technology has landed Google in federal court. On Monday, Judge Leonie Brinkema of the U.S. District Court for the Eastern District of Virginia will preside over the start of a trial in which the Department of Justice accuses the company of abusing control of its ad technology and violating antitrust law.

It would be Google’s second antitrust trial in less than a year. In August, a federal judge ruled in a separate case that Google had illegally maintained a monopoly in online search, a major victory for the Justice Department.

The new trial is the latest salvo by federal antitrust regulators against Big Tech, testing a century-old competition law against companies that have reshaped the way people shop, communicate and consume information. Federal regulators have also filed antitrust lawsuits against Apple, Amazon and Meta, which owns Facebook, Instagram and WhatsApp, saying those companies have also abused their power.

The Justice Department declined to comment on its latest courtroom fight with Google.

Google’s vice president for regulatory affairs, Lee-Anne Mulholland, said in a blog post on Sunday that the Justice Department was “picking winners and losers in a highly competitive industry.”

“With the cost of ads going down and the number of ads sold going up, the market is working,” she said. “The DOJ’s case risks inefficiencies and higher prices — the last thing that America’s economy or our small businesses need right now.”