A Microsoft spokesman declined to comment.
The company said it was cooperating with the Justice Department’s antitrust probe.
Microsoft has been trying to convince regulators to remove the company’s $50 price tag from its software, including the latest version of the “Pac-Man” video-game series.
Microsoft and Nintendo had filed an antitrust complaint in the United States District Court for the Northern District of California on Wednesday.
In addition to the antitrust lawsuit, Microsoft is suing the Federal Trade Commission, accusing it of a “deceptive conduct” scheme and a “fraudulent business practice” that allegedly caused the company to lose money.