A new report is suggesting the Federal Trade Commission (FTC) is considering an antitrust lawsuit to block the Microsoft acquisition of Activision Blizzard.

The report (via Politico) claims “three people with knowledge of the matter” confirm the FTC is “likely” to file an antitrust lawsuit to block the Microsoft / Activision Blizzard merger, which is priced at roughly $69 billion.

The FTC is reportedly “skeptical” of Microsoft’s arguments in defense of the merger, amidst complaints from competitor Sony the deal would be unfair.

Still, no official announcement has been made and Politico says the lawsuit actually happening “is not guaranteed.” The EU has also been investigating the acquisition, also due to concerns of market monopoly should it go through.

Also cited in the report is the Federal Trade Commission’s recent success in blocking the massive merger of book publishers Simon & Schuster and Penguin Random House as what emboldened them to challenge this merger.

Microsoft has already responded to the report, essentially rejecting it wholeheartedly and saying they will fight it tooth and nail:

“Any suggestion that the transaction could lead to anticompetitive effects is completely absurd,” the company said (via Kotaku).

“This merger will benefit gamers and the U.S. gaming industry, especially as we face increasingly stiff competition from abroad. We are committed to continuing to work cooperatively with regulators around the globe to allow the transaction to proceed, but won’t hesitate to fight to defend the transaction if required.”

The FTC was also involved with blocking computing hardware giant Nvidia’s attempt to buy ARM from SoftBank for $40 billion.

The deal fell through due to regulatory hurdles and now SoftBank is supposed to float the semiconductor firm on the stock market next year.