| Madsen Og Moe Holding AS | Real estate | 2015 |
| Madsen Og Moe Prosjekt AS | Real estate | 2015 |
| Madserud Allé 2 AS | Real estate | 2008 |
| Madserud Bistro AS | Hospitality | 2026 |
| Madserud Hage Prosjekt AS | Real estate | 2018 |
| Madsø-Nielsen Invest AS | | 2019 |
| Madt Invest AS | Financial services | 2014 |
| Mae Holding AS | Professional & scientific | 2022 |
| Mae Invest AS | | 2020 |
| Maea Invest AS | | 2025 |
| Maelle AS | Wholesale & retail | 2025 |
| Maelstrom AS | Professional & scientific | 2013 |
| Maema AS | | 2022 |
| Maere Invest AS | | 2024 |
| Maerlie Invest AS | | 2021 |
| Maes AS | | 2026 |
| Maes Invest AS | Real estate | 2015 |
| Maestra Motion Labs AS | Information & communication | 2025 |
| Maestro AS | Information & communication | 2005 |
| Maestro Consulting AS | Professional & scientific | 2015 |
| Maestro Eiendom AS | Real estate | 2013 |
| Maestro Soft AS | Information & communication | 1988 |
| Maeva AS | Wholesale & retail | 2024 |
| Mafe AS | | 2019 |
| Mafe Studios Da | Information & communication | 2025 |
| Mafi Eiendom AS | Real estate | 2013 |
| Mafi Norge AS | Wholesale & retail | 2012 |
| Mafo AS | Financial services | 2005 |
| Mafo Holding AS | Real estate | 2020 |
| Mafor Holding AS | | 2022 |
| Mafor Management AS | Professional & scientific | 2026 |
| Mafri AS | Real estate | 1993 |
| Mafsu AS | | 2021 |
| Mag Capital AS | | 2024 |
| Magali Holding AS | | 2025 |
| Magamadov Holding AS | | 2025 |
| Magan AS | | 2023 |
| Magard Invest 1 AS | | 2026 |
| Magari AS | Information & communication | 2016 |
| Magari Venture AS | Information & communication | 2012 |
| Magas AS | | 2021 |
| Magasinet Drammen Eiendom AS | Real estate | 1996 |
| Magasinet Drammen Eiendomsinvest AS | Real estate | 2020 |
| Magasinet Drift AS | Hospitality | 2026 |
| Magasinet Motor AS | Information & communication | 2026 |
| Magasinparken Invest AS | Real estate | 2018 |
| Magco AS | Financial services | 2020 |
| Magdalenka - Pawel Gregorowicz | Construction | 2009 |
| Mage Dalen AS | Other services | 2021 |
| Magefølelse Invest AS | | 2021 |
| Magellan AS | | 2015 |
| Magellan Capital AS | Financial services | 2013 |
| Magellan I AS | | 2024 |
| Magent AS | Professional & scientific | 2019 |
| Magenta Invest AS | Real estate | 2000 |
| Mager Holding AS | | 2022 |
| Magerøy Medical AS | Health & social care | 2025 |
| Magga Og Anders AS | Information & communication | 2019 |
| Maggie AS | | 2024 |
| Maggieberry AS | Real estate | 2001 |
| Maghreb Import Eksport Ans | Wholesale & retail | 1991 |
| Maghrebtravel Da | Administrative & support | 2004 |
| Magic 8 Productions AS | Information & communication | 2005 |
| Magic Capital AS | Professional & scientific | 2024 |
| Magic Invest AS | Financial services | 2017 |
| Magic Touch Beauty AS | Other services | 2024 |
| Magic Touch Frisør AS | Other services | 2020 |
| Magicbox AS | Real estate | 2003 |
| Magick AS | Education | 2022 |
| Magil AS | Financial services | 2012 |
| Magiske Indiareiser AS | Administrative & support | 2024 |
| Magix AS | Professional & scientific | 2022 |
| Magma Wines AS | Wholesale & retail | 2012 |
| Magmia Invest AS | Real estate | 2002 |
| Magna AS | Professional & scientific | 2022 |
| Magna Construction Management AS | Professional & scientific | 2022 |
| Magna Eiendom AS | Real estate | 2011 |
| Magna Holding AS | Professional & scientific | 2020 |
| Magna Prosjekt AS | Professional & scientific | 2019 |
| Magna Vina AS | Wholesale & retail | 2016 |
| Magnam Bolig AS | Real estate | 2020 |
| Magnasolve AS | Construction | 2025 |
| Magnat AS | Health & social care | 2013 |
| Magnat Corpus Holding AS | Health & social care | 2012 |
| Magnat Corpus Invest AS | Health & social care | 2012 |
| Magnat Hrbitz AS | Professional & scientific | 2015 |
| Magnat Kaffehus AS | Wholesale & retail | 2015 |
| Magnat Medisinske Senter AS | Health & social care | 2021 |
| Magnat Trening AS | Arts & recreation | 2021 |
| Magnate AS | Real estate | 2020 |
| Magnavita AS | Wholesale & retail | 2023 |
| Magne Aasen AS | Wholesale & retail | 1982 |
| Magne Enger Consulting AS | Professional & scientific | 2005 |
| Magne J. Kalstad Photography AS | Professional & scientific | 2018 |
| Magne Lyngner AS | Financial services | 2013 |
| Magne Magler Wiggen Sivilarkitekter Mnal AS | Professional & scientific | 1997 |
| Magne Tuseth AS | Professional & scientific | 1987 |
| Magne Værnes Invest AS | Real estate | 2020 |
| Magnereiser AS | Administrative & support | 2021 |
| Magnesen Holding AS | Professional & scientific | 2016 |