The DOJ action comes after a ProPublica investigation last year found that Texas-based software provider RealPage used algorithms to recommend rents to landlords across the country to maximize profits — a practice that experts said may violate antitrust laws.

In throwing its weight behind plaintiffs in the price-fixing case, the Justice Department waded into a fraught corner of federal antitrust law that could have a wide-reaching impact not only on the way businesses use technology to drive profits but also on the marketplace consumers confront.

In the past, collusion happened with “a formal handshake in a clandestine meeting,” they wrote.

“Algorithms are the new frontier,” federal prosecutors said in their filing. “And, given the amount of information an algorithm can access and digest, this new frontier poses an even greater anticompetitive threat than the last.”

Our thread from last year