| Communications Training Analysis Corp | Business |
| Chamber Transportation Advisory Committee | Business |
| Citywide Transportation Advisory Committee | Business |
| Citizen Transportation Advisory Committee | Business |
| Certification of Truth Accuracy and Completeness | Business |
| Clinical Trials Audit and Compliance | Business |
| Contractor Technical Advisory Committee | Business |
| 1-800 Contacts, Inc. | Business |
| Communications Training Analysis Corporation | Business |
| Community Technical Assistance Center | Community |
| Crooked Tree Arts Center | Community |
| Container Terminal Automation Conference | Community |
| Citroen Traction Avant Club | Community |
| Community Training and Assistance Center | Community |
| Community Technical Assistance Collaborative | Community |
| Cable Technical Advisory Committee | Community |
| Community Technical Aid Centre | Community |
| Center for Trauma And Children | Community |
| Charitable Trust Administration Company | Community |
| Computational Techniques Applications Conference | Computing |
| Creative Audio Codec | Computing |
| Cisco Technical Assistance Center | Computing |
| Carrier Technical Assistance Center | Computing |
| Cerberus Telecom Acquisition Corp | Computing |
| Cyber Threat Analysis Center | Computing |
| Children's Trauma Assessment Center | General |
| Center on Trauma and Children | General |
| Cell Tissue Analysis Core | General |
| Compassion Transparency And Cooperation | General |
| Choice Time Activity Center | General |
| Chromium Trioxide Authorisation Consortium | General |
| Coalition to Transform Advanced Care | General |
| Clinic Technical Assistance Center | General |
| Commercial Technical Assistance Center | General |
| Concrete Testing Adherence Collaboration | General |
| Commercial Targeting and Analysis Center | General |
| Chemical Transportation Advisory Committee | Governmental |
| Cryptologic (administrative) Chief Petty Officer | Governmental |
| Communications Technician (administrative) Chief Petty Officer | Governmental |
| Colonial Tactical Assault Corps | Governmental |
| Citizens Transportation Advisory Committee | Governmental |
| Central Texas Autism Center | Medical |
| Coming Together Against Cancer | Medical |
| Clinical Training and Assessment Center | Medical |
| Clinical Trials Administration Committee | Medical |
| Clinical Teaching and Assessment Center | Medical |
| Center for Army Tactics (formerly Cat and Department of Tactics At Cgsc) | Military and Defence |
| Checo Technical Advisory Committee | Networking |
| Computer Technology Assistance Corps | Technology |
