Acquisition follows rumours of lay-offs and discontent.
The private equity firm Thoma Bravo has bought the app performance company Riverbed Technology for $3.5bn (£2.3bn) in partnership with the pension fund Teachers’ Private Capital.
As part of the deal Riverbed will delist from the Nasdaq stock exchange, with shareholders being paid $21 (£13.9) per share in cash as a result.
Seth Boro, managing partner at Thoma Bravo, said: "Riverbed is a clear industry leader and significant addition to our portfolio of software companies.
"Our team is looking forward to building upon Riverbed’s world class customer support and delivering its market-leading product portfolio to even more enterprise customers."
The decision to turn Riverbed private comes amid rumours of lay-offs at the firm, with one anonymous source telling Business Insider of a "difficult decision" to "streamline our operations".
The deal has been widely attributed to activist investor Paul Singer of Elliott Management, who is thought to have pushed for the sale after a slowdown in Riverbed’s wide area network business.
Jerry Kennelly, chairman and chief executive of Riverbed, said: "With this acquisition now complete, our team can begin to move forward with the strategic initiatives that will take us to the next stage of growth.
"As a private company, Riverbed is better positioned to pursue our long term goals, and has greater flexibility to develop best-of breed technologies that deliver superior application performance for our customers."