The U.S. Federal Trade Commission is seeking to block Microsoft Corp.’s US$69 billion acquisition of Activision Blizzard Inc., saying the tie-up between the Xbox maker and popular gaming publisher would harm competition.

The commission voted 3-1 in favor of the complaint, which was filed in its in-house court. Regulators said Microsoft’s ownership of Activision could hurt other players in the US$200 billion gaming market by limiting rivals’ access to the company’s biggest games. The transaction would turn Microsoft into the No. 3 gaming company, behind Tencent Holdings Ltd. and Sony Group Corp. 

“Microsoft has already shown that it can and will withhold content from its gaming rivals,” said Holly Vedova, director of the FTC’s Bureau of Competition. “Today we seek to stop Microsoft from gaining control over a leading independent game studio and using it to harm competition in multiple dynamic and fast-growing gaming markets.”

An FTC official, speaking anonymously to discuss the complaint, said the agency was concerned that Microsoft could deny access, delay availability or degrade the quality of Activision Blizzard’s most popular titles to rival platforms. Those concerns relate not only to consoles, but also to subscription services and cloud-based gaming, two markets still in development, the official said. A public version of the complaint isn’t yet available.

Microsoft’s proposed Activision Blizzard deal is the company’s largest ever and one of the 30 biggest acquisitions of all time. The transaction would give Microsoft some of the most popular video game franchises, such as Call of Duty and World of Warcraft. The Xbox maker already owns the Halo franchise and Minecraft virtual-world-building game.

“We continue to believe that this deal will expand competition and create more opportunities for gamers and game developers,” said Microsoft President Brad Smith. He said the company is committed to addressing competition concerns and that it offered concessions to the FTC earlier this week. 

“We have complete confidence in our case and welcome the opportunity to present our case in court,” Smith added.

Activision shares fell 1.5 per cent to US$74.76 after falling as much as 3.9 per cent earlier. Microsoft shares rose 1.2 per cent to US$247.40.

In a letter, Activision Blizzard Chief Executive Officer Bobby Kotick assured employees he is confident that the deal will close. 

“The allegations that this deal is anti-competitive doesn’t align with the facts, and we believe we’ll win this challenge,” Kotick said, adding that the combined company would be “good for players,” despite a regulatory environment that he says is “focused on ideology and misconceptions about the tech industry.”

In its release announcing the lawsuit, the FTC cited Microsoft’s decision to make two upcoming titles by newly acquired unit Bethesda Softworks exclusive to Microsoft’s platforms despite assurances the company gave to EU regulators that it had no incentive to withhold games from rival consoles.

The lawsuit is part of an effort by FTC Chair Lina Khan to more aggressively police mergers, particularly those by the biggest tech platforms. Since President Joe Biden appointed her to helm the agency in June 2021, it has killed mergers between Lockheed Martin Corp. and Aerojet Rocketdyne Holdings Inc. as well as Nvidia Corp.’s bid to buy SoftBank Group Corp.’s Arm. The FTC heads to federal court Thursday in San Jose, California, in an effort to block Meta Platforms Inc. from buying a virtual reality startup. 

Although Brazilian antitrust officials cleared the Microsoft-Activision deal in October, other competition regulators, including the UK and the European Union, have also raised concerns. Those two bodies aren’t set to issue decisions on the deal until next year.

Microsoft on Tuesday announced a deal to bring Call of Duty to the Steam PC gaming platform and Nintendo Co. consoles. The company said it’s also offered a proposal that would keep Call of Duty on Sony’s PlayStation for the next 10 years, but the Japanese electronics giant has so far rebuffed efforts to work out a resolution. 

Joost van Dreunen, a video games expert who teaches at New York University’s Stern School of Business, said antitrust authorities have become skeptical of pledges, particularly by the tech platforms, about future behavior. Van Dreunen provided comments on the deal to UK competition officials.

“I don’t think it’s ultimately enough for the FTC to go on,” van Dreunen said of Microsoft’s pledge.

The Redmond, Washington, tech giant sought to placate possible labor concerns about the merger by reaching an agreement with the Communications Workers of America, which also represents employees in the gaming industry. In the pact, Microsoft pledged to take a neutral approach if employees express interest in joining a union. 

The company also said it would stop using noncompete or confidentiality clauses to bar workers from talking about discrimination or harassment as part of a settlement or separation deal. 

The FTC has publicly raised concerns about the use of noncompetes and the impact of mergers on labor conditions.

The agency’s in-house proceedings, overseen by Administrative Law Judge D. Michael Chappell, generally take several months to a year to resolve.