| Luxor Holding AS | Construction | 2025 |
| Luz Electro AS | Construction | 2016 |
| Lycorate AS | Professional & scientific | 2021 |
| Lyrurus AS | Financial services | 2005 |
| Lysne AS | Real estate | 2026 |
| Løiten AS | Wholesale & retail | 1993 |
| Løkenveien 9 AS | Real estate | 2008 |
| Løkkevika Båthavn SA | Transport & logistics | 1994 |
| Løkkåsveien 5 AS | Real estate | 2020 |
| Løsbart AS | | 2024 |
| M Frydenlund Invest AS | | 2026 |
| M Projects AS | Professional & scientific | 2016 |
| M-K Rørlegger Bedrift AS | Construction | 2025 |
| M.J. Invest AS | | 2021 |
| Mabekk Invest AS | Real estate | 2018 |
| Madebynetta AS | Manufacturing | 2022 |
| Mag-Nor Holding AS | Professional & scientific | 2020 |
| Magnolia Eiendom AS | Real estate | 2014 |
| Magnolia System AS | Real estate | 2017 |
| Magway Ren&Bygg AS | Administrative & support | 2021 |
| Mai Selekta AS | Construction | 2021 |
| Majoleer AS | Professional & scientific | 2019 |
| Make Studio AS | Wholesale & retail | 2019 |
| Maldiva AS | Real estate | 2020 |
| Malik AS | Wholesale & retail | 2014 |
| Malkar Invest AS | | 2022 |
| Mamas Søm AS | Other services | 2023 |
| Manova Invest AS | Wholesale & retail | 2001 |
| Mantech AS | Professional & scientific | 2007 |
| Manzetti Consulting AS | Professional & scientific | 2020 |
| Mara Holding AS | | 2005 |
| Maradona AS | Real estate | 2009 |
| Maridalsveien 39 AS | | 1985 |
| Marie Pauline AS | | 2020 |
| Martinfri AS | Professional & scientific | 1997 |
| Martins Agenturer Holding AS | Wholesale & retail | 2005 |
| Maskinering AS | Manufacturing | 1978 |
| Masper Holding AS | | 2022 |
| Master Drinks AS | Wholesale & retail | 2023 |
| Materie X AS | Wholesale & retail | 2021 |
| Matim Engros AS | Wholesale & retail | 2021 |
| Matturer AS | Administrative & support | 2024 |
| Maurtua Barnehage AS | Education | 2023 |
| Mavi Bil AS | Wholesale & retail | 2022 |
| Max Spill AS | Arts & recreation | 1995 |
| MB Eiendomsdrift AS | Real estate | 2026 |
| MCV Invest AS | | 2019 |
| MED24 AS | Construction | 2023 |
| Mediapilotene AS | Professional & scientific | 2009 |
| Medicare-Nor International Services AS | Health & social care | 2012 |
| Medico Legesenter AS | Health & social care | 2014 |
| Medtall AS | | 2019 |
| Meglerhuset Ski AS | Real estate | 2025 |
| Mel Moreppen 22 AS | Real estate | 2024 |
| Meliz Da | Manufacturing | 2006 |
| Melsomvik Holding AS | Administrative & support | 2014 |
| Merdø Vannverk SA | Water & waste | 2011 |
| Mesterbygg Nordby AS | Real estate | 2015 |
| Mestergull Ski Storsenter AS | Wholesale & retail | 1995 |
| Mg-Invest 2 AS | | 2026 |
| Mg-Invest AS | Health & social care | 2021 |
| Mgds AS | | 2025 |
| Microlog AS | Wholesale & retail | 2015 |
| Microslo AS | Health & social care | 2021 |
| Miljøkonsult & Byggteknik AB | Construction | 2000 |
| Mimabo AS | | 2020 |
| Mimoniem AS | Wholesale & retail | 2020 |
| Minel Kreativ Elektro Ski AS | Construction | 2009 |
| Miniprint AS | Professional & scientific | 2020 |
| Mip Holding AS | Wholesale & retail | 2019 |
| Mir Investments AS | Real estate | 2022 |
| Mir Øyeklinikk AS | Health & social care | 2018 |
| Mjølnir Group AS | | 2025 |
| Mjølnir Labs AS | Information & communication | 2025 |
| MK4 Holding AS | | 2026 |
| Mobile Follo AS | Other services | 1977 |
| Mobility 360 AS | Transport & logistics | 2021 |
| Mode AS | Real estate | 2015 |
| Modena Hus AS | Real estate | 2015 |
| Molla Drift AS | Information & communication | 2022 |
| Monetas Invest AS | Professional & scientific | 2007 |
| Monsen Sport Holding AS | Wholesale & retail | 2007 |
| Monsrud Park AS | Real estate | 2020 |
| Monsrudveien AS | Real estate | 2024 |
| Montys Innovation AS | Professional & scientific | 2020 |
| Mora Invest AS | Real estate | 2014 |
| Mordt Holding AS | | 2018 |
| Moreppen C-15 AS | Real estate | 2024 |
| Morgendis AS | | 2022 |
| Motherlode AS | Arts & recreation | 2015 |
| Motor Forum AS | Wholesale & retail | 1979 |
| MPD Invest AS | Professional & scientific | 2021 |
| MR. Opes Holding AS | | 2025 |
| Mrxc AS | Wholesale & retail | 2022 |
| Msng Eiendom AS | Real estate | 2025 |
| Mulighet AS | Information & communication | 2012 |
| Multi Byggservice AS | Construction | 2024 |
| Multiplast AS | Manufacturing | 1997 |
| Murmester K. Svendsen AS | Construction | 2010 |
| My Little Company AS | Information & communication | 2017 |