Microsoft (Nasdaq: MSFT) has closed the acquisition of Skype Global, originally announced in May, for US$8.5bn, Microsoft said in a statement.
Investor group Silver Lake led negotiations for the definitive agreement, previously approved by both companies' boards of directors.
The completion of the acquisition marks the official introduction of Skype as a new business division within Microsoft.
The acquisition remains under review in a few countries, and will be completed there when such reviews are closed.
Skype CEO Tony Bates has been appointed president of the Skype division of Microsoft, reporting directly to Microsoft CEO Steve Ballmer.
The Skype division will continue to offer its current products to users globally. Over the long term, Skype will also be integrated across an array of Microsoft products to broaden its reach and accelerate its growth, the statement reads.
"Together, we will be able to accelerate Skype's goal to reach 1bn users daily," Bates said.
Founded in 2003, Skype was acquired by eBay in September 2005, and then acquired by an investment group led by Silver Lake in November 2009.