- Church Homes Inc.
- Church on the Rock
- Church World Service
- CIGNA Corporation
- Cigna Health Care of Arizona
- Cigna HealthCare
- CIGNA HealthCare
- CIGNA LIFESOURCE Transplant Network
- Cimarron
- Cimarron Express Inc.
- Cincinnati Children's Hospital Medical Center
- Cincinnati Society of Association Executives
- Cincinnati USA Convention and Visitors Bureau
- Cincinnati VA Medical Center
- Cincorcio Caquas-Guayama
- Cinergy
- CIP Print Media
- Circus Hotel Casino Theme Park
- Cisco
- Cisco Brothers Corporation
- Citi Cards OandT Bayamon
- Cities of Cold Casino
- CitiGroup Health Services
- Citizen Bank of Mukwonago
- Citizen Potowatomi Nation
- Citizens Baptist Medical Center
- Citizens Health Center
- Citizens Savings Bank
- City College of New York
- City National Bank of New Jersey
- City of Akron
- City of Albuquerque
- City of Alexandria, VA
- City of Alliance
- City of Apopka
- City of Artesia
- City of Asheville
- City of Atlanta
- City of Austin
- City of Avondale
- City of Bay Village
- City of Beachwood
- City of Bedford
- City of Bedford Heights
- City of Belton
- City of Berea
- City of Bountiful
- City of Brecksville
- City of Brigham City
- City of Broadview Heights