Microsoft's interest in Yammer, known for its social networking functions, could allow the software giant to beef up its offerings for corporations.
A Microsoft spokesman declined to comment. A representative from Yammer did not immediately respond to a request for comment.
Backed by PayPal co-founder and Facebook investor Peter Thiel, Yammer said it counts more than 80 percent of Fortune 500 companies as clients. It raised more than $140 million in venture capital funding.
Bloomberg, which first reported the deal, said the announcement about the transaction was expected at the end of June.
Copyright Thomson Reuters 2012