| Calimero Network | |
| CALIQ Software Ltd | Cambridgeshire |
| Caliso Software | Buckinghamshire |
| Call Centre Management Association | Cheshire |
| Call I.T. | |
| Call Systems Technology | Hertfordshire |
| Calla Lily Personal Care Ltd | Greater London |
| Callagenix Ltd | Buckinghamshire |
| Callender Creates Ltd | East Sussex |
| Callidus | Hertfordshire |
| Callisti Ltd | |
| Calloway Green Ltd | West Midlands |
| Callsign Ltd | |
| Callstream | West Midlands |
| Calm Digital | North Yorkshire |
| Calnex Solutions Ltd | West Lothian |
| Caltag Medsystems Ltd | |
| Caltech IT Ltd | West Yorkshire |
| Caltest Instruments Ltd | |
| Calyo | |
| Calyx | |
| Camb IT Support | Cambridgeshire |
| Cambertronics | Surrey |
| Cambio Ltd | |
| Cambrian Software (UK) Ltd | Gwynedd |
| Cambridge & Counties Bank Ltd | |
| Cambridge Allergy Ltd | |
| Cambridge Analytical Laboratories | |
| Cambridge Angels | |
| Cambridge Bioscience | |
| Cambridge Broadband Networks Group | Cambridgeshire |
| Cambridge Circuit Company Ltd | Cambridgeshire |
| Cambridge Computer Support | Cambridgeshire |
| Cambridge Consultants Ltd | Cambridgeshire |
| Cambridge Electronic Design Ltd | Cambridgeshire |
| Cambridge Electronic Industries Ltd | Cambridgeshire |
| Cambridge Flow Solutions Ltd | Cambridgeshire |
| Cambridge GaN Devices | |
| Cambridge GCSE Computing | Cambridgeshire |
| Cambridge Innovation Capital Manager Ltd | Cambridgeshire |
| Cambridge Mechatronics Ltd | |
| Cambridge Micro Engineering Ltd | Cambridgeshire |
| Cambridge Mobile Communications Ltd | Cambridgeshire |
| Cambridge Network Ltd | Cambridgeshire |
| Cambridge Network Solutions Ltd | Cambridgeshire |
| Cambridge Networks Ltd | Cambridgeshire |
| Cambridge Nucleomics | |
| Cambridge PC Support | Cambridgeshire |
| Cambridge Pharma Ltd | |
| Cambridge Protein Arrays Ltd | |