| Montessoribarnehagene Trondheim AS | Education | 2009 |
| Monument Eiendom AS | Real estate | 2012 |
| Moobot AS | Information & communication | 2021 |
| Moobot Holding AS | Information & communication | 2020 |
| Mooi Klinikken AS | Other services | 2022 |
| Moonduster AS | Administrative & support | 2006 |
| Moonduster Investments AS | | 2024 |
| Mooz Invest AS | Real estate | 2015 |
| Mordi AS | | 2021 |
| More Bio 2 AS | Information & communication | 2022 |
| More Bio AS | Professional & scientific | 2016 |
| More Innovation AS | Agriculture & fishing | 2015 |
| Morefish AS | Professional & scientific | 2014 |
| Morelius AS | Professional & scientific | 2023 |
| Morfem Linguistics AS | Professional & scientific | 2020 |
| Morken AS | Wholesale & retail | 1988 |
| Morken Eiendom AS | Wholesale & retail | 2004 |
| Morken Holding AS | Wholesale & retail | 2005 |
| Morken Transport AS | Transport & logistics | 2021 |
| Morland Otp AS | | 2023 |
| Mormors Stue AS | Hospitality | 1994 |
| Morningstar Records Da | Information & communication | 2005 |
| Moro Eiendom AS | Real estate | 2005 |
| Morroevent Ans | Administrative & support | 2002 |
| MORT1 LARS1 Holding AS | Financial services | 2016 |
| Mortal Garden AS | Information & communication | 2026 |
| Morten Berg Holding AS | Wholesale & retail | 2023 |
| Morten Korsnes AS | Construction | 2005 |
| Morten Stamnes AS | | 2021 |
| Morten Tvenning Invest AS | Real estate | 2017 |
| Mos Create Da | Professional & scientific | 2025 |
| Mosob Restaurant Og Bar Da | Hospitality | 2016 |
| Mostadkaia AS | Real estate | 2007 |
| Mostly Harmless AS | | 2022 |
| Mosvik Barnehageeiendom AS | Real estate | 2026 |
| Motbakken Barnehage SA | Education | 1992 |
| Mothorn Holding AS | Professional & scientific | 2013 |
| Motor Trade Eiendom Og Finans AS | Real estate | 1961 |
| Motor-Handel AS | Wholesale & retail | 2020 |
| Motor-Handel Bilpleie AS | Other services | 2022 |
| Motorconsult AS | Manufacturing | 1998 |
| Motorpsycho Management AS | Arts & recreation | 1998 |
| Moum Eiendom AS | Arts & recreation | 1999 |
| Moum Parkering AS | Real estate | 2015 |
| Moum Trading AS | Wholesale & retail | 2006 |
| Mountain Man Asset Management AS | Financial services | 2018 |
| Mountain Resort Trysil AS | Hospitality | 2010 |
| Mouversi AS | Wholesale & retail | 2008 |
| Moxnes Trafikkskole AS | Education | 2020 |
| Moxto Holding AS | Professional & scientific | 2011 |
| MP Invest AS | | 2017 |
| MPS Bilskade Trondheim AS | Other services | 2013 |
| MR Chuong AS | Hospitality | 1997 |
| MR Fix Trondheim AS | Other services | 2017 |
| MR Investment AS | Real estate | 2019 |
| MR Sideburn Barbershop Ans | Other services | 1992 |
| Mrantonsen AS | | 2026 |
| Mrlyder AS | | 2013 |
| Mrlyder Holding AS | | 2023 |
| MS Starinvest AS | Construction | 2013 |
| Msa Invest AS | Wholesale & retail | 2013 |
| Msagliholte AS | Professional & scientific | 2024 |
| MSD Holding AS | Health & social care | 2023 |
| MSJ Holding AS | Real estate | 2018 |
| MSJ Invest AS | | 2021 |
| Msva AS | | 2020 |
| MT Finans AS | Financial services | 2012 |
| MT Flis AS | Construction | 2022 |
| MT Mal AS | Construction | 2026 |
| MTB Handel AS | Real estate | 2011 |
| MTG AS | Construction | 1986 |
| Mtj-Holding AS | | 2025 |
| MTM Holding AS | Real estate | 2012 |
| Mubarok AS | Financial services | 2014 |
| Muhle Holding AS | | 2023 |
| Muldvarpen Entreprenør AS | Construction | 2024 |
| Mulelid Holding AS | | 2026 |
| Muller & Lintula Ans | Construction | 1997 |
| Multi Renhold Norge AS | Administrative & support | 2011 |
| Multi-Trade AS | | 2006 |
| Multicell Ans | Manufacturing | 1989 |
| Multinet AS | Information & communication | 1995 |
| Multiprosjekt AS | Real estate | 2018 |
| Multiprosjekt Eiendom AS | Real estate | 2015 |
| Multiseis Norway AS | Information & communication | 2008 |
| Multitrading AS | Wholesale & retail | 2016 |
| Mums AS | Real estate | 2017 |
| Munins Veg AS | Real estate | 2017 |
| Munkeg 31 Trondheim Ans | Real estate | 1995 |
| Munkegata 17-19 AS | Real estate | 2011 |
| Munkegata 34/36 AS | Real estate | 2010 |
| Munkegata 44 AS | Real estate | 1989 |
| Munkegata 46 Eiendom AS | Real estate | 1963 |
| Munkegata Eiendom 30 AS | Real estate | 2013 |
| Munkegata Eiendom I AS | Real estate | 2011 |
| Munkegata Eiendom II AS | Real estate | 2011 |
| Munkegata Eiendom III AS | Real estate | 2011 |
| Munkegata Eiendom IV AS | Real estate | 2011 |
| Munkegata Eiendom Ix AS | Real estate | 2011 |
| Munkegata Eiendom V AS | Real estate | 2011 |