- CoastalDx
- Cobble Hill Health Center
- Colavria Hospitality
- Collective Medical
- Colliers International
- Colliers Mortgage
- Colonial Health & Rehab
- Colony Capital
- Colony Northstar Inc.
- Colorado Community College System
- Colorado Health Care Association
- Colorado School of Public Health
- Colorado State Long-Term Care Ombudsman Program
- Colorado State University
- Colquitt Regional Medical Center
- Columbia Pacific Advisors
- Columbia University
- Columbia University School of Nursing
- ComfortMatters
- Commercial Observer