| Covalent Systems | |
| Cove Digital Marketing Ltd | |
| Cove Venture Ltd | |
| Covenco UK Ltd | Oxfordshire |
| Coventry Linux Users' Group | West Midlands |
| Coventry University | West Midlands |
| CoverageBook Ltd | |
| Covey Ltd | |
| CoVi Analytics | |
| COVR Global | |
| Cowan & Partners Ltd | |
| Coyote Software | |
| Cozic Ltd | |
| Cozy Digital Ltd | Edinburgh |
| CozZo | |
| CP Power & Automation Ltd | West Midlands |
| CP&Co | |
| CPIO | |
| CPL Software | |
| CPM Computers Ltd | Cheshire |
| CPT Capital | |
| CPW Computing | Suffolk |
| CQM Learning | |
| CR Systems Ltd | Isle of Wight |
| cr8tech | |
| Cracking Media Ltd | |
| Craft & Slate Creative Agency | |
| Craft I.C.T. Ltd | Norfolk |
| Craft Prospect Ltd | |
| Craftdata Ltd | Buckinghamshire |
| Crafted Media Ltd | Suffolk |
| Craigie Capital | |
| Cram Computers | Lincolnshire |
| Crane Electronics Ltd | Leicestershire |
| Crane Venture Partners | Greater London |
| Cranfield Aerospace Solutions | |
| Cranfield University | Bedfordshire |
| Craven Street Capital Ltd | |
| Craystone Investments Ltd | Greater Manchester |
| Crazy Pumpkin | |
| Cre8 Sales Solutions Ltd | |
| Creandum Advisor, LLP | |
| Creare | |
| Creare Communications | Leicestershire |
| Creasallis | |
| CREATe | |
| Create + Deploy Ltd | |
| Create A Business | |
| Create Data Systems | |
| Create Design Studio | Hampshire |