Oasis Outsourcing, the third-largest PEO in the US, is being acquired by private equity firm Stone Point Capital and management. The deal is expected to be completed by the end of this year; terms of the acquisition were not disclosed.

Oasis is based in West Palm Beach, Fla., and had been a portfolio company of Nautic Partners and Altaris Capital Partners. Nautic acquired the PEO in February 2006 from H.I.G. Capital.

“We are thrilled to partner with Stone Point, one of the nation’s leading private equity firms,” Oasis President and CEO Mark Perlberg said. “With its strong financial support, Oasis will have the opportunity to dramatically escalate our growth, both organically and through strategic acquisitions.”

Perlberg is immediate past chairman of the National Association of Professional Employer Organizations

Oasis serves more than 4,700 small- and medium-sized businesses with more than 160,000 worksite employees in all 50 states and Puerto Rico. The company began in 1996 as a subsidiary of Wackenhut. It posted net revenue of $474 million in 2013 and had a 4 percent market share.

Stone Point Capital is based in Greenwich, Conn.

Staffing Industry Analysts ranks Oasis as the third-largest PEO, but it is privately held. The two larger PEO providers, Insperity Inc. (NYSE: NSP) and ADP (NASD: ADP), are publicly traded.