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.
OM Group OM Group Incorporated is a metal-based chemistry firm based in Cleveland, Ohio, United States. It is a provider of speciality chemicals, advanced materials and technologies. The company was listed on the New York Stock Exchange prior to being privatized by Apollo Global Management in June 2015.