Unlike Google's bid to buy online ad company DoubleClick, the U.S. Federal Trade Commission has allowed Microsoft's deal to buy ad company aQuantive to proceed without further review.
Microsoft announced in May its plan to buy aQuantive for $6 billion, its largest purchase to date.
The FTC requires a 30-day waiting period on large mergers to review antitrust issues, according to FoxNews.com. That period ended Friday without the FTC requesting any more information.
In late May, the FTC made a "second request" for more information about the Google-DoubleClick acquisition, reports Information Week.
Cases that involve a second request for information generally require some modification in the transaction, according to the FTC.
The European Union also is reviewing the DoubleClick Deal, according to Bloomberg News.