| CS-Telecom Deutschland GmbH | Bavaria |
| CS-V computer & software | Baden-Württemberg |
| Cs2 ITEC GmbH & Co. KG | Bavaria |
| CSB - Bruns & Börjes GmbH | Lower Saxony |
| CSB-System AG | North Rhine-Westphalia |
| CSC Computer- und Schulungscenter Fett GbR | Saxony-Anhalt |
| CSci Computer Science UG | Hamburg |
| CSG AUPOS GmbH | North Rhine-Westphalia |
| CSG Systemhaus GmbH | Baden-Württemberg |
| CSI LifeCycle Leasing GmbH | Hesse |
| CSM GmbH | Baden-Württemberg |
| CSM MeinSystemhaus GmbH & Co. KG | North Rhine-Westphalia |
| CSN Elektronik GmbH | Bavaria |
| CSN-Germany GmbH | Baden-Württemberg |
| CSN. Communication Service Network GmbH | North Rhine-Westphalia |
| CSP Computer-Schnittstellen-Peripherie GmbH | Hesse |
| CSS AG | Hesse |
| CSS Computer Security Service GmbH | North Rhine-Westphalia |
| CSW Microcomputer Software GmbH | Bavaria |
| CSW-Datensysteme GmbH | North Rhine-Westphalia |
| CT Computer GmbH | Bavaria |
| CT CoreTechnologie GmbH | Bavaria |
| CT Datentechnik Gesellschaft für Prozessrechentechnik mbH | Lower Saxony |
| CT-Softwareberatungs GmbH | North Rhine-Westphalia |
| CTB Software | Lower Saxony |
| CTC North GmbH | |
| CTF Computerhaus | Bavaria |
| CTI Consulting AG | Hesse |
| CTI New Media GmbH | Berlin |
| CTK Computer Technik Kress | |
| CTM Computer Technik Marketing GmbH | Bremen |
| CTM-COM GmbH | Hesse |
| CTO Software GmbH | North Rhine-Westphalia |
| cts GmbH | Bavaria |
| Cube Biotech GmbH | North Rhine-Westphalia |
| Cube Optics AG | Rhineland-Palatinate |
| Cuesoft GmbH | Baden-Württemberg |
| Cult Consult | Bavaria |
| cultivate GmbH | |
| Cultured Code GmbH & Co. KG | |
| Cultuzz Digital Media GmbH | Berlin |
| Cumin GmbH | Berlin |
| CUP GmbH | Baden-Württemberg |
| Cura-Soft Pflegesoftware GmbH | |
| Cure Digital Finance GmbH | |
| CURE GmbH | |
| Cure53 | |
| CUREosity GmbH | |
| CureVac SE | |
| Curexsys GmbH | |