You’ve read all of your free items this month. To register, get added benefits and unlimited access to articles, Become a Member. Already a Member? Sign in. Advertising Age Article Abstract Martin Sorrell: Publicis-Omnicom Merger an 'Arms Race' Between French and Americans WPP Chief on Holding-Company Rival, Acquisition Strategy and Unilever Cuts By Maureen Morrison, Published on December 09, 2013 6 Want more Access, Content & Connections? Upgrade to Membership. We are glad you are enjoying Advertising Age. To get uninterrupted access and additional benefits, become a member today. Become a Member Already a member? Log in.