The global advertising industry has experienced significant consolidation with a few giant communications companies owning most of the major advertising, branding, public relations, digital marketing, marketing research, and other marketing services agencies. Visit the web sites of the four largest communications groups:

http://www.wpp.com

http://www.omnicomgroup.com/

http://www.interpublic.com

http://www.publicis.com 

For the information they provide about their companies, create a short list of five to ten global advertising agencies that a global marketer might consider working with to create a global advertising campaign and provide advertising services in most major countries.