| IP-Insider | Bavaria |
| IPAddress.com Network UG (haftungsbeschränkt) | Rhineland-Palatinate |
| IPAS Software GmbH | Baden-Württemberg |
| IPB Internet Provider in Berlin GmbH | Berlin |
| IPC-Computer Deutschland GmbH | Baden-Württemberg |
| IPCOMM GmbH | Bavaria |
| IPF Electronic GmbH | North Rhine-Westphalia |
| IPFire | |
| Ipilum GmbH | Berlin |
| IPKS GmbH | Bavaria |
| ipm GmbH | North Rhine-Westphalia |
| ipOcean Global GmbH | |
| iPoint-systems GmbH | |
| Ipolog | |
| Ipoque GmbH | Saxony |
| Ippen Digital GmbH & Co. KG | |
| ipt Solution GmbH | |
| iptoX GmbH | Lower Saxony |
| IQ-optimize Software AG | Hesse |
| IQDoQ GmbH | Hesse |
| IQONEX GmbH | |
| Iqony GmbH | |
| iqs Software GmbH | Baden-Württemberg |
| IQSoft GmbH | Bavaria |
| IQSoftware GmbH | Saxony |
| IR-Systeme GmbH & Co. KG | Bavaria |
| iRealSMS | Schleswig-Holstein |
| Iridium Works GmbH | |
| Iris Biotech GmbH | |
| Iris Biotech GmbH | |
| irisnet GmbH | |
| Iron Mountain Deutschland GmbH | Hamburg |
| Iron Software GbR | Bavaria |
| IronFlock GmbH i.G. | |
| IRS Systementwicklung GmbH | Bavaria |
| IrseeSoft | Bavaria |
| IRUBIS GmbH | |
| IS Intelligent Solution GmbH | |
| iS Software GmbH | Bavaria |
| iS-Fun Internet Services GmbH | Baden-Württemberg |
| IS-Soft.de | Lower Saxony |
| ISA Informationssysteme GmbH | Baden-Württemberg |
| ISA Internet Service Agentur | Hamburg |
| Isa-net | Baden-Württemberg |
| ISACA German Chapter e.V. | Berlin |
| ISAP AG | North Rhine-Westphalia |
| Isar Aerospace Technologies GmbH | |
| Isarna Therapeutics GmbH | |
| IsarNet AG | Bavaria |
| Isarsoft GmbH | |