The U.S. Department of Justice is investigating Microsoft's recent purchases in the video streaming market and has served subpoenas to several companies in the past 10 days. This latest antitrust investigation is centered around whether Microsoft's recent acquisitions are anti-competitive.

"We're looking at the proposed transactions," said Gina Talamona of the Justice Department on Monday. In the past month, Microsoft has purchased VXtreme and a 10% stake in Progressive Networks, makers of Real Audio. Microsoft spokesman Mark Murray said he is confident the probe will be positive for Microsoft.

"We are confident that the Justice Department, once they have reviewed the situation, will agree that all this competition is good for consumers," Murray said