| Content Management AG | North Rhine-Westphalia |
| Content Partners GmbH | |
| Content Software GmbH | |
| Content Technologies GmbH | Bavaria |
| Content-Digital | |
| Content-Koenig.de | |
| Contentbird GmbH | |
| Contentcharge-Media | North Rhine-Westphalia |
| contentXXL | Bavaria |
| Context IT GmbH | Schleswig-Holstein |
| Contextflow GmbH | |
| Contexxt.ai Technologies GmbH | |
| Continental AG | |
| Continental Automotive GmbH | Lower Saxony |
| Continue Software GmbH | North Rhine-Westphalia |
| Continum | Baden-Württemberg |
| CONTIX Consulting GmbH & Co. KG | |
| ContractHero GmbH | |
| Contradigital Agentur | |
| Contrast Marketing GmbH | Bavaria |
| Control Systems GmbH & Co. KG | Baden-Württemberg |
| control.alt.coop e.G. | Berlin |
| Controlware GmbH | Hesse |
| Contronics GmbH Automationssysteme | North Rhine-Westphalia |
| Convelop Ahlbrecht, Bickmann, Zweidar GbR | Bremen |
| Convergit GmbH | Hesse |
| Conversearch GmbH | Berlin |
| conversionmedia GmbH & Co. KG | North Rhine-Westphalia |
| Conversis GmbH | North Rhine-Westphalia |
| ConWeaver GmbH | Hesse |
| Conxai Technologies GmbH | |
| CONXPERT GmbH & Co. KG | Lower Saxony |
| Cookies.games | Hesse |
| Cool Graphiques | Berlin |
| Coolpack Webdesign Düsseldorf | North Rhine-Westphalia |
| coolspot GmbH | North Rhine-Westphalia |
| Cooperativa | Berlin |
| CoopGo.Consulting eG | Bavaria |
| Coparion | North Rhine-Westphalia |
| CopeCart GmbH | |
| Coperion GmbH | |
| Coqui | |
| COR communication | |
| CORAT Therapeutics GmbH | |
| Cordaware GmbH | Bavaria |
| CordenPharma International GmbH | |
| Core Networks GmbH | Hesse |
| Core SE | Berlin |
| Core Sensing GmbH | |
| CoreMedia GmbH | Hamburg |