The US Federal Trade Commission is reviving its challenge against Microsoft's $69 billion acquisition of video game company Activision, a move which may seek to unwind the deal after it closes.

The agency will move forward with its in-house trial against the acquisition after pausing it over the summer, according to an order the agency issued yesterday.

Oral arguments before the Ninth Circuit are scheduled for 6 December, 2023.  Microsoft president Brad Smith said in a blog post last week that 38 signatories have filed nine "friend of the court" briefs in support of the district court's decision to deny any injunctions.

The move means the FTC will continue challenging the deal even after it has closed this year.

"The commission has determined that the public interest warrants that this matter be resolved fully and expeditiously," the agency wrote in a filing. "Therefore, the commission is returning this matter to adjudication."

The decision comes months after a US appeals court denied the FTC's bid to pause the Microsoft-Activision acquisition in July. The FTC typically drops challenges to deals when they lose in federal court, yet for some reason they have not.

The FTC said that if the merger is consummated, it would enable Microsoft—at a key inflection point in a massive and growing industry—to foreclose platform rivals from a leading input provider: Activision, which produces some of the industry’s most popular games.

"At stake, therefore, is whether the emerging subscription and cloud gaming markets will calcify into oligopolistic walled gardens or evolve into open, competitive landscapes, where games are platform-agnostic, new platforms can emerge to challenge established incumbents, and consumers are free to choose where and how to access their games," it said.