| Computerwerkstatt Witte | Bremen |
| Computerwissen | North Rhine-Westphalia |
| Computerwoche.de | Bavaria |
| Computerwork GmbH | Brandenburg |
| ComputerWorks | Baden-Württemberg |
| Computerxtreme.de | Hesse |
| Comramo IT Holding AG | Lower Saxony |
| ComRep GmbH i. L. | Bavaria |
| ComSol AG | North Rhine-Westphalia |
| COMSPOT GmbH | Hamburg |
| COMTEL GmbH | Bavaria |
| COMTEL Studio für Computer und Telekommunikation GmbH | |
| Comtravo | |
| Comtravo GmbH | Berlin |
| comunique Agentur für Marketing-Kommunikation GmbH & Co. KG | North Rhine-Westphalia |
| comvos online medien GmbH | Baden-Württemberg |
| COMwelt media & service | Saxony |
| Comwrap GmbH | Hesse |
| Comyno | |
| con terra GmbH | North Rhine-Westphalia |
| CON4COM!-Werbeagentur | Bavaria |
| Conaito Ltd | Saxony |
| Conasoft Solutions GmbH | |
| Concappt-Media GmbH | |
| Concardis GmbH | Hesse |
| Concept Design GmbH | North Rhine-Westphalia |
| Concept Engineering GmbH | Baden-Württemberg |
| concept-computer Vertriebsgesellschaft mbH | Rhineland-Palatinate |
| Conceptboard | Baden-Württemberg |
| Conceptnet GmbH | Bavaria |
| CONCEPTUM Beteiligungsgesellschaft mbH | |
| Concise Software International GmbH | Berlin |
| Concludata GmbH & Co. KG | |
| Concord Global Services | Bavaria |
| Condalo GmbH | Bavaria |
| Condat AG | Berlin |
| Conductiv.ai | |
| Conectronics GmbH | Baden-Württemberg |
| ConeleK Electronic | Baden-Württemberg |
| CONET Technologies Holding GmbH | North Rhine-Westphalia |
| CoNetSer | |
| ConfTool GmbH | Hamburg |
| confuture Innovationssysteme GmbH | Saxony |
| Congatec AG | Bavaria |
| Congenio GmbH | Bavaria |
| ConIT AG | Baden-Württemberg |
| conIT Gesellschaft für Consulting, Software- Entwicklung und IT-Dienstleistungen mbH | Hesse |
| Conitec Datensysteme GmbH | Hesse |
| ConiuGo GmbH | Brandenburg |
| Conlabz GmbH | Rhineland-Palatinate |