| Mälarvågen AB | Västerås | 0 tkr |
| Malding AB | Västerås | 0 tkr |
| Måleriakuten i Mälardalen AB | Hallstahammar | 0 tkr |
| Malid Konsult AB | Västerås | 0 tkr |
| Malin Rosqvist Holding AB | Västerås | 0 tkr |
| Malin Victoria AB | Västerås | 0 tkr |
| Mallavik Group AB | Västerås | 0 tkr |
| Malmkvist M Holding AB | Kvicksund | 0 tkr |
| Malö Invest AB | Västerås | 0 tkr |
| Malte Engman Holding AB | Västerås | 0 tkr |
| Malte Milovanovic bygg fastighet & alltjänst AB | Köping | 0 tkr |
| MAM Homes Holding AB | Västerås | 0 tkr |
| Mamre invest AB | Sala | 0 tkr |
| MaMy AB | Västerås | 0 tkr |
| Management By Beer MBB AB | Västerås | 0 tkr |
| Manholm Marin AB | Virsbo | 0 tkr |
| Manitech Holding AB | Sala | 0 tkr |
| Manrax Corporation AB | Arboga | 0 tkr |
| Mantellus Group AB | Västerås | 0 tkr |
| Manthey Holding AB | Köping | 0 tkr |
| Mantra AB | Arboga | 0 tkr |
| MA - Ödesberga AB | Arboga | 0 tkr |
| MAQ Management i Västerås AB | Västerås | 0 tkr |
| Maratea Health AB | Västerås | 0 tkr |
| Marbro AB | Västerås | 0 tkr |
| Marcus Öhrbom AB | Östervåla | 0 tkr |
| Marex Consult AB | Västerås | 0 tkr |
| Margareta Löfgren Förvaltning AB | Västerås | 0 tkr |
| Margareta Stendal Holding AB | Västerås | 0 tkr |
| Margaux & Co AB | Västerås | 0 tkr |
| Maria Körkkö AB | Västerås | 0 tkr |
| Mariannes Pizzeria AB | Heby | 0 tkr |
| Marie Lennell AB | Köping | 0 tkr |
| Marielle Malm Förvaltning AB | Norberg | 0 tkr |
| Marin Kolgrill AB | Hallstahammar | 0 tkr |
| Marit Fastigheter AB | Köping | 0 tkr |
| MARK 1989 AB | Västerås | 0 tkr |
| Markedo AB | Stockholm | 0 tkr |
| Mark Holmgren Aktiebolag | Västerås | 0 tkr |
| Markin Holding AB | Västerås | 0 tkr |
| Markstedt Invest AB | Västerås | 0 tkr |
| Marmolux AB | Västerås | 0 tkr |
| Marnefeldt Invest AB | Krylbo | 0 tkr |
| Mårten Blomkvist AB | Kungsör | 0 tkr |
| Mårten Edvardson Förvaltnings AB | Surahammar | 0 tkr |
| Martin Berg Holding Group AB | Västerås | 0 tkr |
| Martin Ek Holding AB | Köping | 0 tkr |
| Martin Linder Västerås AB | Västerås | 0 tkr |
| Martin Lundström Finans AB | Västerås | 0 tkr |
| Martin Wentz Invest AB | Farsta | 0 tkr |