| #2765 | Concern Chaos | ? |
| #2766 | Concord | ? |
| #2767 | Concrete Digital Designs | Z |
| #20094 | Connor [Bearsden Primary 2021] | - |
| #15808 | Conor Brophy | + |
| #2768 | Conor O'Neill | ? |
| #21434 | Conrad Jagger | + |
| #2769 | Conrado Badenas Mengod | ? |
| #2770 | Conradorre Soft | Z |
| #19178 | Conscience | - |
| #23215 | Consciousness | Z |
| #2771 | Consolidated Software Marketing Ltd | Z |
| #2773 | Consult Computer Systems | Z |
| #2774 | Consult Software Ltd | P |
| #2775 | Consumer Electronics Ltd | Z |
| #2776 | Consumers' Association | Z |
| #2777 | Continental Movie Productions | Z |
| #2778 | Continental Software | Z |
| #2779 | Contrast Software | Z |
| #2780 | Control Software | Z |