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 New York City Comptroller Pressures Ad Holding Firms to Release Diversity Stats John Liu Demands Numbers; Omnicom Holding Out, Publicis in 'Similar Situation' By Alexandra Bruell, Published on April 18, 2012 14 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. Register Now Already a member? Log in.