Executive search firm Heidrick & Struggles International Inc. (NASD: HSII) acquired Co Company, a London-based leadership advisory firm.

The transaction closed Oct. 1, and Co Company will integrate into Heidrick & Struggles-branded Leadership Consulting.

The all-cash terms included initial consideration of $10.6 million cash payment at closing, based on 1.52:1 exchange rate, and earn-out structure designed to provide aggregate consideration totaling $15 million to $18 million if Co Company achieves certain revenue and EBITDA margin milestones.

Co Company’s 18 employees operate out of an office in London. Although it has North American full-time employees, the firm utilized a network of affiliated consultants for client work globally, including North America.

“This acquisition is an important marker in the further development of our full complement of leadership advisory services to help our clients achieve transformative results,” said Heidrick President and CEO Tracy Wolstencroft. “The addition of Co Company provides a premium leadership and organizational development capability with tools that can scale globally. It will enhance our ability to work with senior executives around the world to accelerate individual, team and business performance.”

Co Company Chairman Colin Price will lead Heidrick & Struggles’ Leadership Consulting practice globally as executive VP, based in London. He will also serve as a member of the firm's management committee. Three other members of Co Company’s senior leadership team will join Heidrick & Struggles’ Leadership Consulting practice as partners: TA Mitchell, Cathy Powell and Sharon Toye.