| AAronia AG | Rhineland-Palatinate |
| AATec Medical GmbH | |
| AaviGen GmbH | |
| AAZZUR Services GmbH | |
| AB Agentur Berlin | Berlin |
| AB Diagnostic Systems GmbH | |
| AB Innovation GmbH | |
| AB-DATA GmbH & Co. KG | North Rhine-Westphalia |
| AB-Soft GmbH | Bavaria |
| ABACOM Datensysteme GmbH | Lower Saxony |
| ABACOM Ingenieurbüro GbR | Lower Saxony |
| Abacus Digital GmbH | |
| Abacus Software | North Rhine-Westphalia |
| ABAKUS Internet Marketing GmbH | Lower Saxony |
| abakus it AG | Baden-Württemberg |
| abakus-IT SmartCyber GmbH | Hamburg |
| Abalos Therapeutics GmbH | |
| Abanion GmbH | Baden-Württemberg |
| Abas System GmbH | Berlin |
| Abby | |
| ABC GmbH | North Rhine-Westphalia |
| ABC-System GmbH | Hesse |
| Abcalis GmbH | |
| ABCDATA – Thomas Fritsch & Khaled Ben Abed GbR | North Rhine-Westphalia |
| abcfinlab GmbH | |
| Abego Software | North Rhine-Westphalia |
| Abel - Software für Bauingenieure | Baden-Württemberg |
| Abel-Technik e.K. | Lower Saxony |
| Abelnet | Hesse |
| Abelssoft Ascora GmbH | Lower Saxony |
| Abenaa Design 2.18 | Bavaria |
| Aberle GmbH | Baden-Württemberg |
| ABF Software-Systeme GmbH | Hesse |
| Abidat GmbH | Bavaria |
| Abilis GmbH IT-Services & Consulting | Baden-Württemberg |
| ABIS GmbH | Hesse |
| Abisys GmbH | |
| abk-technology GmbH | Hesse |
| Ableton | |
| Abnoba GmbH | |
| ABO Energy GmbH & Co. KGaA | |
| ABO Wind | |
| ABONA Deutschland GmbH | |
| ABOnetX | North Rhine-Westphalia |
| Aborange.de | Hesse |
| Abowire GmbH | |
| abp Automationssysteme GmbH | Hesse |
| ABP Induction Systems GmbH | |
| Abraxas Medien Hamm & Wächter GbR | Bremen |
| ABS Systemberatung Verwaltungs GmbH | Baden-Württemberg |