New York-based Omnicom Group and Paris-based Publicis Groupe have announced a merger that would create the world\'s biggest advertising firm, worth 30 billion US dollars. The combined company will be called Publicis Omnicom Group. The two companies want to bolster their focus on growing Asian and Latin American markets such as China and Brazil. Growth has been lackluster in weak European markets. Publicis CEO Maurice Levy says the move will also allow them to compete for future business from the world’s media giants. He and Omnicom Chief Executive John Wren will jointly lead the new company for the first 30 months. Then Levy will become non-executive chairman and Wren will be CEO. The two veteran CEOs chose the neutral territory of the Netherlands for the new holding company.