Of what nationality are both Dentsply Sirona and Omnicom Group?
Omnicom Group Omnicom Group, Inc. is an American global marketing and corporate communications holding company, headquartered in New York City.
The Marketing Arm The Marketing Arm is a marketing and promotion agency owned by Omnicom Group. With offices in New York City, Los Angeles, Chicago, Dallas and London. The agency specializes in entertainment, sports, cause, event and digital marketing.