Two players in the independent contractor compliance/payrolling space joined forces. ICon Professional Services has acquired Synergy Services.

Both ICon and Synergy were included in Staffing Industry Analysts “2014 contractor payrolling and IC evaluation and compliance landscape” report, which estimated the size of the US contractor payrolling market of $11 billion.

The combined company will have spend under management of $400 million.

Private equity firm Serent Capital orchestrated the deal. San Francisco-based Serent had acquired a majority stake in ICon earlier this year. The ICon-Synergy transaction closed Friday; terms were not announced.

ICon CEO Teresa Creech will remain CEO of the combined firms.

The rapidly growing market's potential to capitalize on opportunities in the independent workforce market proved a motivator for the two firms to join. Creech said the combined company aims to take the best of both firms’ programs. “We will leverage the best of each toolkit and come out with a stronger one on the other end,” Creech said.

Synergy CEO Tim Miller said the combination provides an opportunity to leverage the knowledge of both organizations to serve customers as well as win new accounts through the scale and size of the new organization.

Miller and Synergy President Scott Zirbel will remain with the combined firm for the next few months then transition away from the company.

ICon is based in Foster City, Calif., and was founded in 1997. Serent Capital acquired a majority stake in Icon earlier this year. Synergy is based in Denver and was created in 2001; it has also appeared on previous years’ lists of fastest-growing staffing firms.

“Putting these two incredible growth companies together enables us to better serve the evolving contingent workforce marketplace,” Creech said. “Our clients will benefit from the strongest leadership team in the industry, who are focused on anticipating and addressing the changes in engaging and maximizing independent talent.”