| Caya GmbH | |
| cbb software GmbH | Schleswig-Holstein |
| CBL Datenrettung GmbH | Rhineland-Palatinate |
| CBS Cologne Business School GmbH | |
| cbs Corporate Business Solutions Unternehmensberatung GmbH | Baden-Württemberg |
| CBT Training & Consulting GmbH | Bavaria |
| CBXNET Combox Internet GmbH | Berlin |
| CBZ Landshut GmbH | Bavaria |
| CC CarConsult GmbH | |
| CC e-gov GmbH | Hamburg |
| CC GmbH | Hesse |
| CC-IT GmbH | Baden-Württemberg |
| cc.systems GmbH | |
| CCC City Computer Contor GmbH | Bavaria |
| CCDRD AG | |
| CCE Convenience Coding Equipment GmbH | North Rhine-Westphalia |
| CCNet Computer, Communication & Network GmbH | |
| CCP Software GmbH | Hesse |
| CCT Computertechik AG | Bavaria |
| ccvision GmbH | |
| CD Werbeagentur GmbH | North Rhine-Westphalia |
| CDH AG | Bavaria |
| CDLX GmbH | |
| CDS Computer Demo & Service GmbH | Baden-Württemberg |
| CDS Design & Software Vertriebs GmbH | Berlin |
| CDS GmbH | |
| CDS Peter Griese GmbH | |
| CE-Mat GmbH | |
| Cebacus Ingenieurgesellschaft für EDV-Systeme mbH | North Rhine-Westphalia |
| CebiCon GmbH | North Rhine-Westphalia |
| CeBus-Computer | Hamburg |
| Cedalo GmbH | |
| Ceezer | |
| CeGaT GmbH | |
| Cegrogen Biotech GmbH | |
| cekom GmbH | North Rhine-Westphalia |
| Celares GmbH | |
| Celecta GmbH | Bavaria |
| Celemony Software GmbH | Bavaria |
| Celestica | North Rhine-Westphalia |
| Cellbox Solutions GmbH | |
| Cellbricks GmbH | |
| Cellbricks Therapeutics | |
| Cellbyte GmbH | |
| Cellendes GmbH | |
| Cellex Cell Professionals GmbH | |
| CELLphenomics GmbH | |
| CellServe GmbH | |
| Celonis SE | Bavaria |
| Celtro GmbH | |