| Marias Velvære AS | Other services | 2012 |
| Marie Holding AS | Wholesale & retail | 2023 |
| Marikåpeveien 10 AS | Real estate | 2006 |
| Marin HMS AS | Professional & scientific | 2018 |
| Marin Nordic AS | Wholesale & retail | 2023 |
| Marine Formidling AS | Wholesale & retail | 2026 |
| Marineinvest AS | Wholesale & retail | 2021 |
| Marinix Ocean Tech AS | Professional & scientific | 2018 |
| Marinservice AS | Transport & logistics | 2017 |
| Marisberg AS | Real estate | 2016 |
| Maritech Sør Dampsteam Da | Wholesale & retail | 1997 |
| Maritim Ferie Katamaran.No AS | Wholesale & retail | 2021 |
| Maritim Kompetanse Sørlandet AS | Education | 2025 |
| Maritime Drilling Systems AS | Professional & scientific | 2015 |
| Maritime Konsulenter AS | Professional & scientific | 2018 |
| Maritime Protection AS | Manufacturing | 2009 |
| Maritronic & Kristiansand Båtservice AS | Manufacturing | 2007 |
| Marius Knudsen AS | Manufacturing | 2021 |
| Markens Gate 11-15 AS | Real estate | 2021 |
| Markens Gate 44 Da | Real estate | 1988 |
| Markens Gate 46 AS | Real estate | 1989 |
| Markens Gate 8 AS | Real estate | 2006 |
| Markens Grøde AS | Real estate | 1999 |
| Markens Magasin AS | Real estate | 1962 |
| Markensgate 2 AS | Real estate | 2005 |
| Markensgate 25 AS | Real estate | 2022 |
| Markensgate 35 AS | Real estate | 2019 |
| Markensgate 42 AS | Real estate | 2021 |
| Markensgate 46A AS | Real estate | 2009 |
| Markensgate 5 AS | Real estate | 2017 |
| Markensgate 9 AS | Real estate | 2008 |
| Markensgaten 17 Invest AS | Real estate | 2005 |
| Markensgaten 19 AS | Real estate | 2008 |
| Markensgaten 30 AS | Real estate | 2007 |
| Markensgt 22 AS | Real estate | 2003 |
| Markenssgt 30 Hjemmel Ans | Real estate | 1987 |
| Marketing & Comms AS | Professional & scientific | 2024 |
| Markus Kalsnes Invest AS | | 2024 |
| Marmelade Design AS | Professional & scientific | 2011 |
| Marmia AS | | 2021 |
| Marrneta AS | | 2023 |
| Marshall Trading AS | Wholesale & retail | 2008 |
| Marthe Strædet Babysvømming AS | Education | 2014 |
| Martin Bencher (Norway) AS | Transport & logistics | 2013 |
| Martin Hennig-Olsen AS | Financial services | 2004 |
| Martinsen Equity AS | | 2024 |
| Marum & Co AS | Professional & scientific | 2023 |
| Marum AS | Professional & scientific | 2000 |
| Marvika Holding AS | Real estate | 2011 |
| Marvika Orlogstasjon AS | Real estate | 2018 |
| Marvika Senter Bolig AS | | 2017 |
| Marvika Senter Butikk 1 AS | Real estate | 2017 |
| Marvika Senter Butikk 2 AS | Real estate | 2017 |
| Marvika Senter Butikk 3 AS | Real estate | 2017 |
| Marvika Senter Butikk 4 AS | Real estate | 2017 |
| Marvika Senter Butikk 5 AS | Real estate | 2010 |
| Marvika Senter Holding AS | Real estate | 2014 |
| Marvika Utvikling Holding AS | Real estate | 2013 |
| Marvikahjørnet AS | Real estate | 2020 |
| Marviksletta Eiendom AS | Real estate | 1955 |
| Marviksletta Utvikling AS | Real estate | 2016 |
| Marvisto AS | Professional & scientific | 2006 |
| Marvold & Christensen AS | Hospitality | 2024 |
| Marynett AS | Wholesale & retail | 2005 |
| Maskin & Auto Service Sør AS | Other services | 2007 |
| Maskin & Transport Da | Administrative & support | 1999 |
| Maskinentreprenør Flåt AS | Administrative & support | 2021 |
| Maskinentreprenør Monan AS | Construction | 2019 |
| Maskinpartner Sør AS | Wholesale & retail | 2025 |
| Maskinteknikk Sør AS | Manufacturing | 2020 |
| Maso Eiendom AS | Professional & scientific | 2014 |
| Masoro AS | Professional & scientific | 2026 |
| Massasje, Helse Og Skjønnhet AS | Other services | 2021 |
| Massive Universe AS | Information & communication | 2026 |
| Massivtre Holding AS | Real estate | 2022 |
| Massivtre Invest AS | Real estate | 2022 |
| Masto Wireservice AS | Wholesale & retail | 1981 |
| Mat & Mening AS | Hospitality | 2013 |
| Mat & Smak AS | Hospitality | 2026 |
| Mat Og Folk AS | Administrative & support | 2026 |
| Match Invest AS | | 2024 |
| Materialrommet AS | Wholesale & retail | 2017 |
| Mats Marken AS | Professional & scientific | 2023 |
| Matta AS | Real estate | 2014 |
| Mattehelten AS | Education | 2024 |
| Maurtua Barnehage SA | Education | 1993 |
| Mavat AS | Real estate | 2018 |
| Mawu AS | | 2023 |
| Max Hansen Invest AS | Financial services | 2014 |
| Max Holding AS | Real estate | 2016 |
| Maxi Catering AS | Hospitality | 2015 |
| Maxi Produksjon AS | Manufacturing | 2024 |
| Maxi Servering AS | Other services | 2010 |
| Maytek AS | Professional & scientific | 2017 |
| MB Shipbrokers Norway AS | Transport & logistics | 2022 |
| MB Systua AS | Manufacturing | 2021 |
| Mba Invest AS | Wholesale & retail | 1997 |
| Mbi AS | Wholesale & retail | 2019 |
| MBS Solutions AS | Information & communication | 2023 |
| MBV AS | Real estate | 2019 |