| CAD Services | Essex |
| CAD User Magazine | Greater London |
| Cad-Capture | Lancashire |
| CADagency | |
| Cadan Design Digital | |
| CADCentre UK | Swansea |
| Caddie Software | Bedfordshire |
| Cademy | |
| Cadenergy Ltd | Fife |
| CADify | |
| CADline | Surrey |
| CADlogic Ltd | Staffordshire |
| Cado Security | |
| CADS | Dorset |
| CADS Ltd | Derbyshire |
| Cadspec | Worcestershire |
| CADsultants Ltd | Greater London |
| Caeli Nova | |
| Caesar | |
| Cagan Tech Ltd | |
| Caged Fish | |
| Cairn Research | |
| Cairngorm Capital | Greater London |
| Caistar | Denbighshire |
| CaJSoft Ltd | |
| Cake Agency | |
| Cal Partners Ltd | |
| CAL Services UK Ltd | Somerset |
| Calculus Software Solutions Ltd | |
| Calderdale College | |
| Calderdale Computer Services | West Yorkshire |
| Caledonian Cables Ltd | East Sussex |
| Caletech International Ltd | Angus |
| Caliach Ltd | Devon |
| Calica Computer Solutions | |
| Calico UK | Highland |
| Caligo Ltd | Channel Islands |
| 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 | Dumfries and Galloway |
| Calloway Green Ltd | West Midlands |
| Calls9 Ltd | |