The Federal Trade Commission will be taking a closer look at the respective purchases of Right Media by Yahoo and of aQuantive by Microsoft, reports AdAge.

The initial review is part of what's called the Hart-Scott-Rodino process, meant to ensure no problems are encountered with the deals. In cases where more information is necessary, the FTC will issue a second request to the parties being investigated.

So far neither Yahoo nor Microsoft has received notice of a second request.

A pair of ad industry groups have asked the FTC to review the wave of recent acquisitions to make sure the marketplace is not unduly stifled. The FTC has not said whether it would review the WPP Group buyout of agency 24/7 Real Media. It has, however, issued a second letter seeking information in its review of the Google purchase of DoubleClick.

The government agency reviews almost all major transactions of this nature.