| CrossEngage | Berlin |
| CrossLend GmbH | |
| CrossMedia Consulting | |
| CrossVentures GmbH | North Rhine-Westphalia |
| Crowd Guru | Berlin |
| Crowd Technologies GmbH | |
| Crowder | |
| Crowdfox GmbH | |
| Crowdpark Games & Entertainment GmbH | Berlin |
| Crowntronic Kommunikationsberatung | Hamburg |
| CRP Informationssysteme GmbH | Rhineland-Palatinate |
| CRS Clinical Research Services Management GmbH | |
| CRX Markets AG | |
| Cryptomator | North Rhine-Westphalia |
| CryptoMotors UG (haftungsbeschränkt) | |
| CryptoPhone | |
| CrystalsFirst | |
| Crytek GmbH | Bavaria |
| CS ComputerService | Rhineland-Palatinate |
| CS Hard & Software Consulting GmbH | Saarland |
| CS Inventory Software | Bavaria |
| CS Stöber | Hesse |
| CS-Informationstechnik | Hesse |
| CS-Multimedia GmbH | Baden-Württemberg |
| 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 | |