Microsoft Corp has agreed to buy LinkedIn Corp for $US26.2 billion ($A35.5 billion) in its biggest-ever deal, combining the software giant's fast-growing cloud services business with the world's largest online network for professionals.
The offer of $US196 per share represents a premium of 49.5 per cent to LinkedIn's Friday closing price.
LinkedIn's shares were jumped 48 per cent to $US194.28 before the opening bell on Monday.
Microsoft's shares were down 3.3 per cent.
"Today is a re-founding moment for LinkedIn," Reid Hoffman, chairman of LinkedIn's board, said in a statement.
Jeff Weiner will remain chief executive of LinkedIn, reporting to Microsoft CEO Satya Nadella.
"I have always had a great admiration for LinkedIn," Nadella said in a video on Microsoft's website.
"I have been talking with Reid and Jeff for a while ... I have been thinking about this for a long time."
The deal is expected to close in 2016, the companies said in a joint statement.
Microsoft said it would issue new debt to fund the deal.
After the deal, LinkedIn will become part of Microsoft's productivity and business processes unit.
