| Mbi Trafikkskole AS | Education | 2021 |
| MBS International AS | Agriculture & fishing | 2017 |
| MBT Bluestar Ltd Nuf | Wholesale & retail | 2009 |
| MBT Icona AS | Information & communication | 2014 |
| MBT Invest AS | | 2022 |
| MC- & Bilutleie AS | Administrative & support | 1996 |
| Mca Invest AS | Real estate | 2017 |
| Mca Mercur Corporate Advisors AS | Professional & scientific | 2013 |
| Mcallister Eiendom AS | Real estate | 2008 |
| Mct-Institutt Limited Nuf | Education | 2008 |
| Mct-Online AS | Health & social care | 2020 |
| Mcti Invest Limited Nuf | | 2008 |
| Mctorget Ans | Information & communication | 2000 |
| Mdco Midt-Norge AS | Health & social care | 2022 |
| Mde Trondheim AS | Administrative & support | 2022 |
| MDG1 AS | Real estate | 2018 |
| MDP Holding AS | | 2025 |
| MDT Holding AS | | 2021 |
| Meau AS | Information & communication | 2024 |
| Medbric AS | Information & communication | 2024 |
| Medbø Invest AS | | 2021 |
| Meder Johnsen Og Fiskerstrand Ans | Professional & scientific | 1988 |
| Medialab AS | Wholesale & retail | 2008 |
| Medical Solutions Group AS | | 2025 |
| Medicus Group AS | Health & social care | 2021 |
| Medicus Oculus AS | Health & social care | 2008 |
| Medicus Trondheim AS | Health & social care | 1997 |
| Medident Helse AS | Health & social care | 2012 |
| Medident Trondheim AS | Health & social care | 1997 |
| Mediehuset Nidaros AS | Information & communication | 2019 |
| Mediehuset Rotsekk AS | Information & communication | 2022 |
| Medium Ingeniørtjenester AS | Professional & scientific | 1998 |
| Medoral AS | Health & social care | 2014 |
| Medvind Kapital AS | Real estate | 2021 |
| Medvind Media AS | Professional & scientific | 2015 |
| Medvind Utvikling AS | Information & communication | 2026 |
| Megaton Holding AS | | 2026 |
| Megleren Din AS | Real estate | 2011 |
| Megleronline Eiendomsmegling AS | Real estate | 2006 |
| Mego AS | Professional & scientific | 1983 |
| Meidell Holding AS | Financial services | 2018 |
| Meierikvartalet Eiendom AS | Real estate | 2006 |
| Meland Holding AS | Professional & scientific | 2011 |
| Melands Eiendom AS | Real estate | 2015 |
| Melands Holding AS | Construction | 2015 |
| Melands Rørservice AS | Construction | 2015 |
| Melen Holding AS | Professional & scientific | 2025 |
| Melhus Bil Trondheim AS | Other services | 1987 |
| Melhus Bolig AS | Real estate | 2006 |
| Melhus Catering AS | Hospitality | 2021 |
| Melhus Eiendomsutvikling AS | Real estate | 2004 |
| Melhus Fysioterapi AS | Health & social care | 1987 |
| Melhus Gravstein AS | | 2021 |
| Melhus Ideplan AS | Real estate | 2007 |
| Melhus Kjøpesenter AS | Real estate | 2002 |
| Melhus Vaktmesterservice AS | Administrative & support | 1997 |
| Melhus Vaktmesterservice II AS | Administrative & support | 2019 |
| Melhustunet 2 AS | Real estate | 2018 |
| Melhustunet AS | Real estate | 2018 |
| Melhustunet S12 AS | Real estate | 2021 |
| Melhusvegen 393 AS | Real estate | 2022 |
| Melhuus AS | Professional & scientific | 2012 |
| Melle Holding AS | | 2024 |
| Mellingsæter Holding AS | Financial services | 2022 |
| Mellomformat AS | | 2020 |
| Mellomila 57 Da | Real estate | 2015 |
| Mellomila 79-81 AS | Real estate | 2012 |
| Mellomrom AS | Arts & recreation | 2022 |
| Mellomveien 12A Og 12B AS | Real estate | 2025 |
| Mellomveien 16 AS | Real estate | 2023 |
| Mellomveien 9 AS | Real estate | 2025 |
| Mellomveien AS | Hospitality | 2013 |
| Melon AS | Wholesale & retail | 2019 |
| Melore Creative AS | Information & communication | 2026 |
| Melting Holding AS | | 2018 |
| Melø Holding AS | Professional & scientific | 2022 |
| Memo Capital AS | Financial services | 2017 |
| Mengden AS | | 2021 |
| Menito AS | Information & communication | 2026 |
| Menomed AS | Professional & scientific | 2026 |
| Mental Audio AS | Information & communication | 2013 |
| Menti Verdi AS | Wholesale & retail | 2023 |
| Mentor Eiendom AS | Real estate | 2009 |
| Menx Invest AS | Financial services | 2016 |
| Mer Av Gruppen AS | Professional & scientific | 2026 |
| Merbevegelse AS | Education | 2017 |
| Mercatur AS | Information & communication | 2023 |
| Mercur Cap 1 AS | | 2022 |
| Mercur Capital AS | | 2018 |
| Meride AS | Administrative & support | 1998 |
| Meritorius AS | Real estate | 1994 |
| Merlin Kids Lade AS | Wholesale & retail | 2020 |
| Merlin Kids Trondheim AS | Wholesale & retail | 2019 |
| Mersalg AS | Wholesale & retail | 1994 |
| Merula AS | Wholesale & retail | 2014 |
| Mes AS | Financial services | 2009 |
| Mesa Invest AS | | 2025 |
| Mesial Holding AS | Health & social care | 2023 |
| Messi Invest AS | | 2021 |
| Messier 1 Holding AS | | 2025 |