| Marienlyst Eiendom AS | Real estate | 2023 |
| Marienlyst Parkering AS | Real estate | 1999 |
| Marili Da | Wholesale & retail | 2023 |
| Marine Control Services AS | Professional & scientific | 2001 |
| Markedstjenester AS | Professional & scientific | 2015 |
| Markens Grøde Av Jonatan Bukkøy-Tindholm Arntzen AS | Hospitality | 2023 |
| Markveien Invest AS | Real estate | 2023 |
| Marron Eiendom AS | Real estate | 2021 |
| Marte E.J. Holding AS | | 2020 |
| Marteli AS | Wholesale & retail | 2021 |
| Martin Fevang AS | Financial services | 2005 |
| Martinsen Dagligvare AS | Wholesale & retail | 2015 |
| Martspaw AS | Manufacturing | 2025 |
| Marvarconthe AS | Hospitality | 2023 |
| Marwil Carbon AS | Administrative & support | 2021 |
| Marwil Energy Holding AS | Energy | 2018 |
| Mas Helse AS | Health & social care | 2026 |
| Masala Milkshake AS | Health & social care | 2013 |
| Masarch AS | Wholesale & retail | 2026 |
| Mascot International Norge AS | Wholesale & retail | 2005 |
| Maskin-Elektrisk AS | Manufacturing | 1970 |
| Mason Invest AS | | 2023 |
| Mast Consulting AS | Professional & scientific | 2009 |
| Mat Holding AS | Hospitality | 2005 |
| Mataba Consulting AS | Professional & scientific | 2018 |
| Materialkompasset AS | Information & communication | 2026 |
| Matfikseren AS | Hospitality | 2005 |
| Math Holding AS | Real estate | 2019 |
| Math Invest AS | Financial services | 2018 |
| Maverik AS | Other services | 2021 |
| Mavold Holding AS | | 2023 |
| Max Borg Holding AS | Wholesale & retail | 2020 |
| Max-Event AS | Administrative & support | 2009 |
| MBB Elektro AS | Other services | 2022 |
| MBM Holding AS | | 2015 |
| MC Eiendom AS | Real estate | 2010 |
| MC Invest AS | Arts & recreation | 2005 |
| Mconsult Renhold AS | Administrative & support | 2013 |
| Mctiga Holding AS | | 2024 |
| MD Klinikken AS | Health & social care | 2024 |
| MDR Invest AS | Administrative & support | 2011 |
| Me & My Cousin Gulskogen AS | Wholesale & retail | 2022 |
| Me Eier AS | | 2023 |
| Mecc AS | Construction | 2022 |
| Med X AS | Health & social care | 2021 |
| Med-Hus AS | Health & social care | 2014 |
| Mederud Holding AS | Real estate | 2023 |
| Media Group AS | Professional & scientific | 2024 |
| Medicinae AS | Health & social care | 2015 |
| Medikalteknikk AS | Manufacturing | 2015 |
| Mediplast AS | Wholesale & retail | 2005 |
| Mega Bygg & Mal AS | Construction | 2024 |
| Meganett Da | Information & communication | 2001 |
| Meglerhuset & Partners Drammen AS | Real estate | 2015 |
| Mehlums Skiservice AS | Arts & recreation | 2021 |
| Mehren Revisjon AS | Professional & scientific | 2003 |
| Meinseth Invest AS | | 2018 |
| Meistad IT Consulting AS | Information & communication | 2013 |
| Meka Holding AS | | 1990 |
| Mekanisme Norge AS | Wholesale & retail | 2024 |
| Mekong Kjøkken AS | Hospitality | 2019 |
| Meli Jewelry and Accessories AS | Wholesale & retail | 2022 |
| Melina Hår & Velvære AS | Other services | 2022 |
| Melius Staffco AS | | 2024 |
| Memento Mori AS | | 2022 |
| Mensendieck Da | Health & social care | 1999 |
| Mento Invest AS | Financial services | 2008 |
| Mep Holding AS | | 2026 |
| Mepro Rør AS | Construction | 2013 |
| Mercedes Marine Company Ltd | | 2001 |
| Merhebia Finest AS | Wholesale & retail | 2018 |
| Mesa Libre AS | Hospitality | 2022 |
| Mester Blikk Og Tak AS | Construction | 2010 |
| Metallgjenvinning AS | Water & waste | 2024 |
| Metalltak AS | Manufacturing | 2023 |
| Meti Transport AS | Transport & logistics | 2024 |
| Metrion AS | Professional & scientific | 2026 |
| Mevu AS | Wholesale & retail | 2022 |
| Meybak Holding AS | | 2025 |
| Mfa Entertainment AS | Arts & recreation | 2019 |
| MFB Invest AS | | 2026 |
| Mfold Invest AS | | 2020 |
| MFS AS | Wholesale & retail | 2015 |
| MG Montering AS | Construction | 2026 |
| MG Trade AS | Wholesale & retail | 2024 |
| MGH Eiendom AS | Real estate | 2021 |
| MGK Holding AS | | 2022 |
| MGM AS | Real estate | 2022 |
| Mhes Holding AS | Professional & scientific | 2005 |
| Mhjohannessen AS | Professional & scientific | 2007 |
| Mi Arkitektur + Design AS, Maria Ibarra Sivilarkitekt Mnal | Professional & scientific | 2014 |
| Mi Casa AS | Wholesale & retail | 2003 |
| Mias Klinikk AS | Health & social care | 2025 |
| Mice Invest AS | Real estate | 2018 |
| Mida Transport AS | Transport & logistics | 2023 |
| Midgard Games AS | Wholesale & retail | 2015 |
| Midje Invest AS | | 2000 |
| Mied Eiendom AS | Real estate | 2025 |
| Mikrochip AS | Other services | 2018 |
| Mikrofilm Og Dokumentsystemer Norge AS | Wholesale & retail | 1994 |