Private equity firm Atairos Group Inc. is acquiring a 26% ownership stake in professional employer organization Trinet Group Inc. (NYSE: TNET) in a deal announced last week. The deal will give Atairos a 28% share in the PEO, valued at approximately $440 million.

Atairos is acquiring the shares from General Atlantic and the deal represents the entire remaining stake held by General Atlantics, which first invested in TriNet 11 years ago.

As part of the deal, Atairos Chairman and CEO Michael Angelakis will join TriNet’s board. In addition, David Hodgson, managing director of General Atlantic, will continue to serve on TriNet’s board.

Plans call for the deal to be completed in the first quarter.

“Atairos has used the Trinet platform for our own HR needs since we established our company — and we have experienced firsthand the compelling value proposition that TriNet offers small and midsize businesses,” Angelakis said. “Based on our experience and industry research, we invested in Trinet and also approached General Atlantic about acquiring their ownership position.”