- Cascadia Consulting Group
- CDC
- Center for Evaluation Innovation
- Center for Responsible Business
- Center to Advance Palliative Care
- Centre for Development Innovation, Wageningen University and Research Centre
- Centre for Social Impact, University of New South Wales
- CHS Alliance
- Collective Impact Forum
- Colorado Trust
- Community Science
- Community TechKnowledge
- Council on Foundations
- DAC Network on Development Evaluation
- David and Lucile Packard Foundation
- Donor Committee for Enterprise Development (DCED)
- E. T. Jackson & Associates, Ltd.
- Engage R+D
- Equal Measure
- Ernst & Young Societe d'Avocats
