| Maran Wind AS | Transport & logistics | 2026 |
| Marathon Invest AS | Professional & scientific | 2005 |
| Marble Productions AS | Professional & scientific | 2017 |
| Marbles AS | Wholesale & retail | 2014 |
| Marco Polo Holding AS | | 2005 |
| Mardoll AS | Real estate | 2014 |
| Mareco AS | Administrative & support | 2018 |
| Marehalm AS | | 2026 |
| Maren Tollagsen AS | Health & social care | 2025 |
| Mareno AS | Professional & scientific | 1988 |
| Margrethe Jørgensens Vei 13 AS | Real estate | 2017 |
| Margurame AS | | 2021 |
| Mari Evensen Holding AS | | 2021 |
| Marianne Harling AS | Health & social care | 2021 |
| Marie Solenes Nieuwlaat AS | | 2025 |
| Mariebo Utvikling AS | Real estate | 2019 |
| Marielunden Næring AS | Real estate | 2014 |
| Marielunden Services AS | Administrative & support | 2014 |
| Mariero Foodcourt AS | Hospitality | 2015 |
| Mariero Holding AS | Financial services | 2013 |
| Mariero Invest AS | Financial services | 2010 |
| Mariero Mat AS | Wholesale & retail | 2021 |
| Marierogaarden AS | Real estate | 2004 |
| Marieroholding AS | Administrative & support | 2015 |
| Marimi AS | Real estate | 2006 |
| Marin-E AS | Professional & scientific | 2022 |
| Marinius Handel Sør AS | | 2024 |
| Marinpet AS | Manufacturing | 1999 |
| Marinus Invest AS | Professional & scientific | 2020 |
| Marit Skibenes Invest AS | | 2025 |
| Maritime Design AS | Professional & scientific | 1998 |
| Maritime Energy Service AS | Construction | 2017 |
| Maritime Supply Ans | Manufacturing | 1991 |
| Marius Westbø AS | Financial services | 2005 |
| Mark Arkitekter AS | Professional & scientific | 2013 |
| Mark Eiendomsutvikling AS | Real estate | 2013 |
| Mark Gruppen AS | Professional & scientific | 2013 |
| Markedshagen Da | Wholesale & retail | 2022 |
| Marketendo Growth Boy AS | | 2026 |
| Marketing Companiet Da | Other services | 1993 |
| Markveien 25 AS | Real estate | 2025 |
| Marlog AS | Transport & logistics | 1997 |
| Marnda Holding AS | | 2025 |
| Marsli AS | Professional & scientific | 2025 |
| Martech Capital AS | Real estate | 2014 |
| MARTHINS1 Holding AS | | 2020 |
| Martin Feldmann Tannteknikk AS | Manufacturing | 2010 |
| Martin Sport Media AS | Arts & recreation | 2019 |
| Martinique AS | Hospitality | 1990 |
| Marton Eiendom AS | Real estate | 2021 |
| Marton Invest AS | Real estate | 2005 |
| Marton Kapital AS | Real estate | 1980 |
| Martracon Shipmanagement Norway AS | Administrative & support | 2021 |
| Marudi AS | | 2007 |
| Marulk AS | Professional & scientific | 2012 |
| Marvik Holding AS | Professional & scientific | 2005 |
| Marås Holding AS | Financial services | 2014 |
| Marøi Invest AS | | 2005 |
| Mas Ans | Wholesale & retail | 1996 |
| Mas Bygg AS | Real estate | 2016 |
| Masa Invest AS | Professional & scientific | 2022 |
| Maseto Holding AS | Wholesale & retail | 2022 |
| Masgo AS | Professional & scientific | 2001 |
| Mashua Invest AS | Financial services | 2015 |
| Masio Vedlikehold & Service AS | Construction | 2017 |
| Maskin Vest AS | Wholesale & retail | 2025 |
| Maskinveien 12 AS | Real estate | 1973 |
| Maskinveien 14 AS | Real estate | 1977 |
| Maskinveien 16 AS | Real estate | 2018 |
| Maskinveien 19 AS | Real estate | 2008 |
| Maskinveien 30 AS | Real estate | 2008 |
| Maskinveien AS | Real estate | 2014 |
| Masova AS | | 2025 |
| Mass Consulting AS | Professional & scientific | 2021 |
| Mass Holding AS | | 2022 |
| Masso Holding AS | | 2014 |
| Masterproject AS | Professional & scientific | 2018 |
| Masterstone AS | Professional & scientific | 2015 |
| Mastr Consulting AS | Professional & scientific | 2025 |
| Masy AS | Financial services | 2005 |
| Mat Og Trening AS | Arts & recreation | 2016 |
| Mat-Kuling Vannbehandling AS | Professional & scientific | 2020 |
| Matae Stavanger AS | Professional & scientific | 2025 |
| Matboden K8 AS | Wholesale & retail | 2015 |
| Matboden Management AS | Professional & scientific | 2024 |
| Matboden Rogaland AS | Hospitality | 2002 |
| Match-Eiendom AS | Real estate | 2023 |
| Matcompaniet AS | Wholesale & retail | 2001 |
| Matflix AS | Manufacturing | 2017 |
| Mathew Leong Holding AS | | 2025 |
| Mathias Molden Holding AS | Financial services | 2018 |
| Mathiassen Maskin AS | Construction | 2011 |
| Matin Invest AS | | 2022 |
| Matmagasinet AS | Hospitality | 2006 |
| Matre Eiendom AS | Real estate | 2023 |
| Matros Stavanger AS | Hospitality | 2021 |
| Mats Rasmussen AS | Financial services | 2017 |
| Matsafari AS | Administrative & support | 2011 |
| Matsalen AS | Hospitality | 2008 |
| Matu AS | | 2023 |