As evidenced by its A-list clients and double-digit growth, Cone's specialist focus serves it well. Expansion into CSR draws from, and builds upon, its core strengths.

"We've purposely taken a relatively narrow focus [and] business model strategy," Jens Bang, president and CEO, says. "We're uniquely positioned because our four disciplines are interrelated. We try to develop depth of talent that allows us to compete at the highest level. We go narrower and deep so we can attract that kind of client ...