Principals: Jack Martin, global chairman and CEO (r); Dan Bartlett, US president and CEO
Ownership: WPP
Subsidiary agencies: Public Strategies, Blanc & Otus, Wexler Walker Public Policy Associates, Piranha Kid
Offices: 82 wholly owned globally; 17 in the US
Revenue: Global: $300 million to $400 million; US: $100 million to $200 million
Hill & Knowlton underwent sweeping changes in 2010 and early 2011, but its new leaders claim the H&K-Public Strategies union will lead to a best-in-class global firm.