F.T.C. Said to Plan to Sue to Stop Microsoft’s Activision Deal From Closing

The Federal Trade Commission plans to sue Microsoft on Monday to stop the company from closing its $69 billion purchase of the video game powerhouse Activision Blizzard, escalating the federal government’s efforts to stymie the largest consumer technology deal in decades, two people with knowledge of the matter said.

The move was the latest regulatory challenge to Microsoft’s blockbuster deal for Activision, which has become a test case for whether behemoth tech companies can complete major acquisitions amid a backlash to the power of the firms.

Last year, the F.T.C. sued to block Microsoft’s purchase of Activision through an in-house court, arguing it would damage competition in various parts of the video game market. The agency is filing the separate lawsuit because unlike the F.T.C.’s in-house court, a federal court can issue a restraining order to block a deal from being completed.

In April, the British Competition and Markets Authority also moved to block the deal, though regulators in the European Union said it could go forward.

An F.T.C. spokesman did not immediately respond to a request for comment.

In a statement, Brad Smith, the president of Microsoft, said the company welcomed the “opportunity to present our case in federal court.”