The deal, valued at $68.7 billion, was announced last month by Microsoft. As part of the proposed deal, Microsoft would take in Activision's 10,000 employees and gain control of the popular gaming franchises Call of Duty, Warcraft, Diablo, Overwatch, and Hearthstone.
If approved, the $68.7 billion deal would become Microsoft's largest acquisition to date.
While both the FTC and Department of Justice both have authority in conducting antitrust enforcement, only the FTC will be involved in this merger review, Bloomberg reported.
The FTC will reportedly look at whether Microsoft, which makes Xbox consoles, merging with Activision would harm competition by limiting rivals' access to major game titles.
Microsoft's acquisition of Activision could face tough scrutiny, with the FTC and the Justice Department's antitrust divisions jointly announcing last month that they would rewrite guidance for mergers. In that announcement, both departments noted US industries had become concentrated in recent years and a surge in merger filings over the past two years threaten to worsen the situation.
The Microsoft-Activision deal comes amidst a flurry of gaming deals, with Sony on Monday announcing it will acquire Bungie for $3.6 billion, which is best known for creating the popular gaming franchises Halo and Destiny. Even the New York Times threw its hat in the gaming arena this week with its decision to acquire the viral word game Wordle for a "price in the low seven figures".