| Mathisen Capital AS | | 2026 |
| Mathisen Consulting AS | Professional & scientific | 2009 |
| Mathisens Fisk AS | Wholesale & retail | 2016 |
| Mathjørnet Ans | Wholesale & retail | 1996 |
| Mathma AS | Financial services | 2005 |
| Mathor Holding | | 2022 |
| Mathus Grill AS | Hospitality | 2013 |
| Mathus Holding AS | | 2024 |
| Mathuset AS | Real estate | 1967 |
| Matial Bygg AS | Real estate | 2021 |
| Matias Myklebust AS | Information & communication | 2024 |
| Matic AS | Health & social care | 2024 |
| Matilda Grennberg Invest AS | Professional & scientific | 2022 |
| Matiné AS | Wholesale & retail | 2026 |
| Matiss Bygg AS | Construction | 2025 |
| Matjakt SA | Wholesale & retail | 2017 |
| Matjos AS | | 2022 |
| Matka AS | Financial services | 2005 |
| Matkassa AS | Hospitality | 2021 |
| Matkjellern Sharma & Co Ans | | 1993 |
| Matlaget AS | Information & communication | 2020 |
| Matle Holding AS | | 2022 |
| Matler AS | Professional & scientific | 2017 |
| Matlykke Holding AS | | 2023 |
| Matmar AS | Financial services | 2008 |
| Matmons AS | | 2021 |
| Matmums AS | Wholesale & retail | 2015 |
| Mato Eiendom Holding AS | Real estate | 2022 |
| Matoas AS | | 2026 |
| Matoja AS | Real estate | 2014 |
| Matoma Productions AS | Information & communication | 2015 |
| Matooke AS | Wholesale & retail | 2021 |
| Matorika AS | Real estate | 2018 |
| Matre AS | Professional & scientific | 2023 |
| Matricaria AS | Wholesale & retail | 2020 |
| Matriks AS | Wholesale & retail | 1999 |
| Matrix Advokater AS | Professional & scientific | 2015 |
| Matros AS | Financial services | 2016 |
| Matrospynten AS | Financial services | 2008 |
| Matruska AS | | 2020 |
| Matry Invest AS | | 2024 |
| Mats & Martin AS | Hospitality | 2009 |
| Mats Eriksen Holding AS | Real estate | 2015 |
| Mats Holding AS | | 2021 |
| Mats Johan Pedersen Holding AS | | 2022 |
| Matsco AB | Construction | 2002 |
| Matsemann Edb AS | | 2021 |
| Matspecialen AS | Hospitality | 1995 |
| Matstream AS | Information & communication | 2019 |
| Matt Holding AS | Real estate | 2009 |
| Matt Invest AS | Real estate | 2005 |
| Matte.No AS | Education | 2025 |
| MATTE100 AS | Education | 2017 |
| Mattehuset AS | Education | 2018 |
| Matter AS | Professional & scientific | 2020 |
| Matter Non-Athlete AS | Wholesale & retail | 2026 |
| Matterhorn AS | | 2007 |
| Matterhorn Capital AS | | 2019 |
| Matterhorn Konsult AS | Administrative & support | 2020 |
| Mattias Skytters Vei 2 AS | Real estate | 2005 |
| Mattinata AS | | 2024 |
| Mattis AS | | 2005 |
| Mattis Herman Nyquist AS | Arts & recreation | 2022 |
| Mattise Holding AS | Administrative & support | 2025 |
| Mattisholmen AS | | 2025 |
| Mattlin Finans AS | Financial services | 2025 |
| Mattlin Holding AS | | 2025 |
| Matty Cash AS | Information & communication | 2025 |
| Matulf Investerings Selskap AS | | 2026 |
| Matuma Invest AS | | 2021 |
| Maturitas AS | Financial services | 1990 |
| Maturus AS | Professional & scientific | 2015 |
| Matvett AS | Professional & scientific | 2012 |
| Matværste Holding AS | Real estate | 2024 |
| Maud Eiendomsinvest AS | Real estate | 2010 |
| Maud Group AS | | 2026 |
| Maud Music AS | Information & communication | 2024 |
| Maud Ocean AS | Professional & scientific | 2026 |
| Mauds Manufaktur AS | Wholesale & retail | 2019 |
| Maukon Invest AS | | 2020 |
| Maulund | Wholesale & retail | 2015 |
| Mauna Kea AS | | 2019 |
| Mauped Invest AS | | 2022 |
| Maur Bygg Håp AS | Construction | 2022 |
| Maur Tipp Og Slep AS | Real estate | 1989 |
| Maurice Holding AS | | 2023 |
| Maurice Performance Nuf | Education | 2019 |
| Mauritz AS | Real estate | 2016 |
| Mauritz Hansensgate 4 AS | | 2025 |
| Mauritz Invest AS | | 2024 |
| Mauritz Kartevolds Plass 1 AS | Real estate | 2007 |
| Maurtek AS | Financial services | 2016 |
| Maurtua Holding AS | Education | 2010 |
| Maurtua Private Barnehage AS | Education | 2010 |
| Maurtuen AS | Real estate | 2014 |
| Maurtvedt Consulting AS | Professional & scientific | 2023 |
| Mausetvegen 526 AS | Real estate | 2020 |
| Mav Invest AS | Information & communication | 2018 |
| Mava Group AS | Hospitality | 2024 |
| Mavass AS | Education | 2014 |