| M2Soft GmbH | North Rhine-Westphalia |
| M3 Connect GmbH | North Rhine-Westphalia |
| M94 GmbH | North Rhine-Westphalia |
| ma-x neue Medien GmbH | Saarland |
| Maas Elektronik | North Rhine-Westphalia |
| Maas Holding GmbH | Baden-Württemberg |
| MAB Discovery GmbH | |
| Mable GmbH | |
| mac check - Apple Reparaturen, Support, Consulting | Berlin |
| MAC IT-Solutions GmbH | Schleswig-Holstein |
| Mac User Leipzing | Saxony |
| Maccon GmbH | Bavaria |
| MACH AG | Schleswig-Holstein |
| Machart Studios GmbH | |
| Machbar GmbH | Hesse |
| mackenroth.net | Hamburg |
| Maclabor GmbH | Bavaria |
| Macle GmbH | North Rhine-Westphalia |
| MacLife | Schleswig-Holstein |
| Macnotes.de | Brandenburg |
| Macrix Software GmbH | |
| macroIS GmbH | Bavaria |
| MacroSystem | Schleswig-Holstein |
| Macsentials | Bavaria |
| MacTrade GmbH | Bavaria |
| mad.Design GmbH | |
| MADA Marx Datentechnik GmbH | Baden-Württemberg |
| Maddox AI GmbH | |
| Mader-Schuler Datentechnik GmbH | Bavaria |
| Madge GmbH | Bavaria |
| Madness GmbH | Baden-Württemberg |
| maf-pap Internet Services | Schleswig-Holstein |
| MagaLoop GmbH | |
| MaganaMed GmbH | |
| Magazino GmbH | Bavaria |
| Magelan | Bavaria |
| magellan netzwerke GmbH | North Rhine-Westphalia |
| MagForce AG | |
| MagForce NT GmbH | |
| Magicline GmbH | Hamburg |
| MagicMaps GmbH | Baden-Württemberg |
| Magicpix | North Rhine-Westphalia |
| MagicSeries | Hamburg |
| Magig | |
| MAGIX Software GmbH | Berlin |
| Magmell GmbH | |
| Magnet-Schultz GmbH & Co. KG | |
| Magnetec GmbH | |
| Magnise GmbH | |
| magnolia4 GmbH | North Rhine-Westphalia |