| Acceed GmbH | North Rhine-Westphalia |
| Accelerator Frankfurt | Hesse |
| Accellence Technologies GmbH | Lower Saxony |
| Accemic Technologies GmbH | Bavaria |
| Accentize GmbH | |
| AcceptIT GmbH | North Rhine-Westphalia |
| Access-Profi-Pool e.V. | Berlin |
| accis Systemhaus Gesellschaft für neue Medien mbH | Berlin |
| ACCURE Battery Intelligence GmbH | North Rhine-Westphalia |
| ACE-Solutions | Baden-Württemberg |
| AceBIT GmbH | Hesse |
| ACELR8 | |
| Acent AG | Berlin |
| Acento | Schleswig-Holstein |
| Achim Dräger und Raffael Burgardt GbR | Saarland |
| Achim Schlemmer | Baden-Württemberg |
| Achim ZWICK HR Consulting | Hamburg |
| acht und drei e.K. | |
| Achteins | Hesse |
| Acio | Lower Saxony |
| Ackermann Automation GmbH | |
| ackermann-consulting.de | North Rhine-Westphalia |
| Acolada GmbH | Bavaria |
| ACom PC | Berlin |
| Acondistec GmbH | |
| ACONI GmbH | Lower Saxony |
| Aconno GmbH | |
| Acontis Technologies GmbH | Baden-Württemberg |
| Acosoft GmbH | Saxony |
| Acotec GmbH | North Rhine-Westphalia |
| Acousia Therapeutics GmbH | |
| Acrolinx GmbH | |
| Acrolinx GmbH | |
| ACSYS Lasertechnik GmbH | |
| ACT Angewandte Computer Technik GmbH | Schleswig-Holstein |
| act! consulting GmbH | Hamburg |
| ActeaVentures GmbH | |
| ACTech GmbH | |
| Actimage GmbH | |
| Actindo AG | Bavaria |
| Actinium Consulting GmbH | Bavaria |
| Action-Team Schön | Baden-Württemberg |
| Actisis GmbH | Rhineland-Palatinate |
| ActiTrexx GmbH | |
| Active Data | Lower Saxony |
| Active Group Gesellschaft für computergestützte Kommunikationslösungen mbH | Baden-Württemberg |
| Active Logistics AG | North Rhine-Westphalia |
| Active Online GmbH | North Rhine-Westphalia |
| Active-Websight | North Rhine-Westphalia |
| ActiveTraining | Baden-Württemberg |