Phaidon International, whose US operations ranked among the fastest-growing staffing firms, was acquired by Quilvest Private Equity. In addition, Phaidon founder Adam Buck will be stepping back.

The acquisition was completed recently and announced today. However, financial terms of the deal were not disclosed.

“Quilvest stood out because of its international relationships and reach, as well as the quality of its team,” Phaidon CEO Harry Youtan said. “I have no doubt that they will help us to fulfill our vision of becoming the go-to partner of choice for STEM partners worldwide. I would also like to pay tribute to our founder, Adam Buck, who will be stepping back from Phaidon following the transaction. Adam has been instrumental in building Phaidon into the successful business it is today.”

London-based Phaidon was founded in 2004 and has 10 locations around the world — including New York, Hong Kong and Zurich.

Its US operations have ranked on Staffing Industry Analysts’ list of fastest-growing staffing firms based on US revenue. It ranked No. 6 on the 2017 list with a compound annual growth rate of 83.0%.

“We see Phaidon as a unique player in a highly attractive, fast-growing sector,” Jay Takefman, partner at Quilvest Private Equity, said. “Over the coming years, we intend to further support the company’s growth, both in existing and new markets internationally and across its portfolio of renowned brands whilst staying true to its values-based, meritocratic culture.”