| Mare Liberum AS | Real estate | 1989 |
| Mare Venti AS | | 2018 |
| Marella Adventures AS | | 2020 |
| Maren Fredbo AS | Information & communication | 2020 |
| Maren Furulunds Veg 20 AS | Real estate | 2018 |
| Maren Furulunds Veg 22 AS | Real estate | 2020 |
| Maren Helle AS | Professional & scientific | 2017 |
| Maren Smedseng AS | Health & social care | 2024 |
| Marenco Investments Ltd | Mining & quarrying | 2001 |
| Marengo Invest AS | | 2025 |
| Marenlundveien 5 AS | Real estate | 2009 |
| Marenlundveien 6 AS | Real estate | 2005 |
| Mares Holding AS | Manufacturing | 2023 |
| Maresante Mental Helse AS | Health & social care | 2024 |
| Marevita AS | | 2026 |
| Marfri Invest AS | | 2020 |
| Marg Invest AS | | 2022 |
| Margana Productions AS | Information & communication | 2019 |
| Margarinfabrikken Norena AS | Real estate | 1946 |
| Margarit Og Svensson Ans | Information & communication | 1989 |
| Margaux AS | Financial services | 1976 |
| Margentum AS | Financial services | 1998 |
| Marger 2000 KFT | Construction | 2011 |
| Margil Holding AS | | 2023 |
| Margin AS | Financial services | 1990 |
| Margin Invest AS | | 2021 |
| Margin of Safety AS | Financial services | 2014 |
| Margine AS | | 2023 |
| Marginer AS | | 2026 |
| Margjein Invest AS | Financial services | 2005 |
| Margo Manufaktur AS | Manufacturing | 2024 |
| Margrethe Jørgensens Veg 1 E AS | Real estate | 2007 |
| Margrethe Nygaard Holding AS | Real estate | 2009 |
| Margus Holding AS | Professional & scientific | 2012 |
| Marhaba Norway AS | Professional & scientific | 2023 |
| Marhag Invest AS | | 2025 |
| Marhaug Holding AS | Real estate | 2022 |
| Marhema AS | | 2022 |
| Marher Invest AS | | 2025 |
| Marhold AS | | 2023 |
| Mari Capital AS | | 2025 |
| Mari Eiendom AS | Real estate | 2024 |
| Mari Hjorteset Holding AS | | 2020 |
| Mari Hofgaard AS | | 2023 |
| Mari Igesund Sivilarkitekt AS | Professional & scientific | 2019 |
| Mari Isdahl Holding AS | | 2023 |
| Mari Kollektiv AS | Hospitality | 2025 |
| Mari Moen Holsve AS | Arts & recreation | 2022 |
| Mari Nordén AS | Manufacturing | 2018 |
| Mari Rognlien AS | Information & communication | 2012 |
| Mari SK Holding AS | | 2025 |
| Mari Sommerfeldt AS | Wholesale & retail | 2017 |
| Maria Alibrahim AS | Hospitality | 2024 |
| Maria Ans | | 1993 |
| Maria Black Jewellery Norge AS | Manufacturing | 2015 |
| Maria Dehlis Vei 40 AS | Real estate | 2016 |
| Maria Groener AS | | 2021 |
| Maria Holding AS | Real estate | 2005 |
| Maria Nakken AS | | 2022 |
| Maria Nilsdotter AS | Wholesale & retail | 2025 |
| Maria Pettersen AS | Information & communication | 2026 |
| Maria Skappel Holzweiler AS | Wholesale & retail | 2021 |
| Marianne Gjesvik Holding AS | Financial services | 2017 |
| Marianne Holding AS | | 2019 |
| Marianne Jemtegård AS | Arts & recreation | 2022 |
| Marianne Noren AS | Professional & scientific | 2024 |
| Marianne Og Morten AS | Professional & scientific | 2023 |
| Marianne Ruud AS | Health & social care | 2022 |
| Marianne S AS | Real estate | 2016 |
| Marianne Stein Holding AS | Financial services | 2007 |
| Mariannes Hus AS | Education | 2022 |
| Mariarty Holdning AS | | 2024 |
| Maribel AS | Hospitality | 2017 |
| Mariboes Gate 13 AS | Real estate | 2016 |
| Mariboes Gate 6-8 Holding AS | Real estate | 2020 |
| Mariboesgt 6-8 AS | Real estate | 2022 |
| Maribu Eiendom AS | Real estate | 2014 |
| Maridalen Barnehage SA | Education | 1984 |
| Maridalen Brenneri AS | Manufacturing | 2017 |
| Maridalen Invest AS | Financial services | 2012 |
| Maridalsveien 10 AS | Real estate | 2007 |
| Maridalsveien 154 AS | Real estate | 2021 |
| Maridalsveien 188 AS | Real estate | 2015 |
| Maridalsveien 266D Holding AS | Real estate | 2024 |
| Maridalsveien 271 AS | Real estate | 2018 |
| Maridalsveien 295 AS | Real estate | 1999 |
| Maridalsveien 319-321 AS | Real estate | 2006 |
| Maridalsveien 323 AS | Real estate | 2006 |
| Maridalsveien 52 AS | Real estate | 2017 |
| Maridalsveien 85-87 AS | Real estate | 2006 |
| Maridalsveien 89 AS | Real estate | 1997 |
| Maridalsveien 9 B Ans | Real estate | 1998 |
| Maridalsveien 91 AS | Real estate | 2018 |
| Maridalsveien Boligutvikling AS | Real estate | 2012 |
| Maridalsveien Smådyrklinikk AS | Professional & scientific | 2001 |
| Marie & Co. AS | Professional & scientific | 2024 |
| Marie Gaup Paulsrud AS | Wholesale & retail | 2021 |
| Marie K AS | Information & communication | 2020 |
| Marie Louise Tank AS | Education | 2004 |
| Marie Melania AS | Education | 2021 |