| Madame Beyer AS | Real estate | 2022 |
| Mads Bones Holding AS | Arts & recreation | 2021 |
| Maejs AS | Construction | 2015 |
| Magbra Holding AS | | 2024 |
| Maghan Invest AS | Financial services | 2016 |
| Magic Moment AS | Arts & recreation | 2022 |
| Magne Nordnes AS | Professional & scientific | 2018 |
| Magne Rosvold Transport AS | Transport & logistics | 1998 |
| Magnitud Invest AS | | 2020 |
| Magnum AS | Financial services | 2005 |
| Magnus Lagabøters Veg 2 AS | Real estate | 2021 |
| Magnus Lagabøters Veg 4A AS | Real estate | 2017 |
| Magnus Lagabøters Vei 6 Invest AS | Real estate | 2019 |
| Magnus Lagabøters Vei 8 AS | Real estate | 2009 |
| Magnusmagnus AS | Professional & scientific | 2005 |
| Magrator AS | Information & communication | 2026 |
| Maha Holding AS | | 2020 |
| Mahalingam AS | Wholesale & retail | 2022 |
| Mahan Holding AS | | 2022 |
| Mahø Holding AS | | 2024 |
| Maija AS | Wholesale & retail | 2025 |
| Maintech AS | Professional & scientific | 1986 |
| Maisma AS | | 2019 |
| Maison Alma Mater AS | Wholesale & retail | 2014 |
| Maix AS | Hospitality | 2019 |
| Majo Trondheim AS | | 2005 |
| Majoni Invest AS | Financial services | 2005 |
| Major Bricks Da | Arts & recreation | 2024 |
| Maju AS | Financial services | 2005 |
| Mak-Bud AS | Construction | 2022 |
| Make My Day AS | Wholesale & retail | 2015 |
| Makk AS | | 2026 |
| Makootate AS | Manufacturing | 2022 |
| Mala Utvikling AS | Real estate | 2020 |
| Malarella Holding AS | | 2026 |
| Maldito Da | Arts & recreation | 2022 |
| Maler Dahl AS | Construction | 2017 |
| Malerfirma Jomar Utnes AS | Construction | 1998 |
| Malerkompaniet AS | Construction | 1991 |
| Malermester Blakstad AS | Construction | 1991 |
| Malermester Evensen & Meland AS | Construction | 2013 |
| Malermester Håkon Opdal AS | Construction | 2005 |
| Malermester Kjeldsberg AS | Construction | 2016 |
| Malermester Kurt I Hermstad AS | Construction | 2023 |
| Malermester Morten Hvidsten AS | Construction | 2025 |
| Malermester Petter Utne AS | Construction | 2018 |
| Malermester Sture Brækstad AS | Construction | 1996 |
| Malewi Holding AS | | 2025 |
| Malik Taxi AS | Transport & logistics | 2017 |
| Maliks Kreativ AS | Arts & recreation | 2023 |
| Malin Reitan Ltd Nuf | Arts & recreation | 2011 |
| Malling & Co Trondheim AS | Real estate | 2025 |
| Malmfuru Holding AS | | 2025 |
| Malo Teis AS | Real estate | 2021 |
| Malodal AS | Construction | 2006 |
| Malolo Eiendom AS | Professional & scientific | 2017 |
| Malosta Holding AS | Real estate | 2019 |
| Mama AS | Hospitality | 2025 |
| Mamarosa Pizzeria Da | Hospitality | 2006 |
| Mamas & Tapas Da | Arts & recreation | 2005 |
| Mamato AS | Hospitality | 2024 |
| Management 15 AS | Professional & scientific | 2015 |
| Mandarinsaft Da | Arts & recreation | 2011 |
| Manes Mip Da | Arts & recreation | 2014 |
| Mango Enterprise AS | Hospitality | 2023 |
| Mango Invest AS | Financial services | 2005 |
| Manico Holding AS | Professional & scientific | 2021 |
| Manjana AS | | 2024 |
| Manjaro AS | Real estate | 2016 |
| Mankowsky Malerservice AS | Construction | 2022 |
| Manstad-Hulaas Invest AS | | 2020 |
| Mapheim AS | Information & communication | 2022 |
| Mar Nutrition Holding AS | | 2020 |
| Mar Viking AS | Agriculture & fishing | 2020 |
| Maramu AS | Professional & scientific | 2018 |
| Maraqua Consulting AS | Professional & scientific | 2021 |
| Marbek Invest AS | | 2018 |
| Marbro AS | | 2025 |
| Marcel Consortium AS | | 2025 |
| Marcelius AS | Hospitality | 2014 |
| Marcello Lippi AS | Real estate | 2015 |
| Marcus Berg Eiendom AS | Real estate | 1990 |
| Marcus Johansen Holding AS | | 2025 |
| Marenius Invest AS | Financial services | 2013 |
| Marfie AS | | 2020 |
| Margaringården 2 AS | Real estate | 2026 |
| Margaringården II AS | Real estate | 2026 |
| Margrete Solvang AS | Health & social care | 2026 |
| Mari Aursand Holding AS | | 2021 |
| Mari Holding AS | Real estate | 2014 |
| Maria Collections AS | Wholesale & retail | 2024 |
| Maria Rydning AS | Real estate | 2007 |
| Maria-Sofie Holding AS | Hospitality | 2025 |
| Maribu Invest AS | | 2005 |
| Marienborg Eiendom AS | Real estate | 2020 |
| Marin Aqua AS | Professional & scientific | 2016 |
| Marin Odysse AS | Administrative & support | 2004 |
| Marina Coast AS | Professional & scientific | 2004 |
| Marine & Industri Power Midt-Norge AS | Administrative & support | 2018 |
| Marine AS | Information & communication | 2007 |