| Miss Pizza AS | Hospitality | 2020 |
| MJ Drift AS | | 2019 |
| MJ Transport AS | Transport & logistics | 2025 |
| Mo Holding Grimstad AS | Wholesale & retail | 2022 |
| Mobile Arendal AS | Wholesale & retail | 2016 |
| Mobile Autocar AS | Other services | 1975 |
| Modellteknikk Arendal AS | Manufacturing | 2016 |
| Moe Group AS | Wholesale & retail | 2023 |
| Moesec AS | Wholesale & retail | 2023 |
| Moland Andelslandbruk SA | Agriculture & fishing | 2017 |
| Moland Park AS | Real estate | 2018 |
| Moland Utvikling AS | Real estate | 2020 |
| Molandsveien 199 AS | Real estate | 2021 |
| Molandsveien 203 AS | Real estate | 2021 |
| Molandsveien 207 AS | Real estate | 2021 |
| Molandsveien 245 AS | Real estate | 2022 |
| Molandsveien 27A AS | Real estate | 2024 |
| Molandsveien 335-337 AS | Real estate | 2020 |
| Molldøra Eiendom AS | Real estate | 2010 |
| Moltemyrskogen Barnehage AS | Education | 2022 |
| Mona AS | Real estate | 1999 |
| Mona Hauglid Foto AS | Professional & scientific | 2016 |
| Monika Praljak Voigt AS | Health & social care | 2023 |
| Monk AS | Real estate | 2020 |
| Montasje-Team V/Dirk P. Trommer AS | Construction | 2023 |
| Moonde AS | Information & communication | 2020 |
| Morrow Batteries ASA | Manufacturing | 2014 |
| Morrow Industrialization Center AS | Manufacturing | 2014 |
| Morrow Technologies AS | Professional & scientific | 2012 |
| Morten Midtstøl AS | Transport & logistics | 2026 |
| Morten Venemyr AS | Professional & scientific | 2013 |
| Mosvald Marine Management AS | Professional & scientific | 2016 |
| Motehår AS | Other services | 2011 |
| Motor-Teknikk Sør AS | Real estate | 1985 |
| Motunet Birkeland AS | Real estate | 2026 |
| MPBN4 AS | Real estate | 2021 |
| MPBN5 AS | Real estate | 2021 |
| Mpolo AS | Hospitality | 2023 |
| Mpolo ST. Hanshaugen AS | Hospitality | 2021 |
| MR. Know How AS | Wholesale & retail | 2015 |
| MS Consulting AS | Professional & scientific | 2023 |
| MS Nidelv AS | Transport & logistics | 2013 |
| MSK Bil AS | Wholesale & retail | 2013 |
| MTB Byggservice AS | Construction | 2013 |
| Multi Montasje AS | Construction | 2012 |
| Multiflis AS | Construction | 2008 |
| Multiteam Sør AS | Construction | 2019 |
| Munnhulen Tannklinikk AS | Health & social care | 2025 |
| Murmester Jan Arild Johannesen AS | Construction | 2014 |
| Murmester Sekkenes AS | Construction | 2014 |
| MW Media AS | Information & communication | 2022 |
| Myhren Logistikk AS | Professional & scientific | 2003 |
| Myra Biovarme AS | Energy | 2011 |
| Myra Dagligvare AS | Wholesale & retail | 2004 |
| Myra Haircare AS | Other services | 2019 |
| Myrene Hjemmebakeri Arendal AS | Manufacturing | 2025 |
| Myrene Pizza AS | Hospitality | 2005 |
| Myrene Pizza Invest AS | Manufacturing | 2017 |
| Myrene Sushi AS | Hospitality | 1998 |
| Myreneveien 21 AS | Real estate | 2026 |
| Myreneveien 25 AS | Real estate | 2021 |
| Myreneveien 32 AS | Real estate | 2008 |
| Myreneveien AS | Real estate | 2020 |
| Myrseth Invest AS | Real estate | 2006 |
| Møbelringen Arendal AS | Wholesale & retail | 2002 |
| Møbeltapetsererverkstedet AS | Manufacturing | 2020 |
| Mørland Eiendom AS | | 2020 |
| Mørland Sko AS | Wholesale & retail | 1973 |
| Mørlandsmoen Bilopphogging AS | Wholesale & retail | 1995 |
| Nahla Invest AS | | 2023 |
| Naildress Studio AS | Other services | 2025 |
| Namsvatn Skogpleie AS | Agriculture & fishing | 2024 |
| Natalia Ivanivna AS | Health & social care | 2023 |
| Naturheller Og -Stein Nuf | Mining & quarrying | 2007 |
| Nautnes Panorama AS | Real estate | 2021 |
| Nedenes Invest AS | Manufacturing | 2024 |
| Nedenes Torg AS | Real estate | 2024 |
| Nedenes Vekst AS | Real estate | 2013 |
| Nedig AS | Construction | 1997 |
| Nedig Group AS | | 2026 |
| Nedig Group Invest AS | | 2026 |
| Nedig Invest AS | | 2026 |
| Nemko System Sikkerhet AS | Information & communication | 2016 |
| Nemus Arendal AS | Health & social care | 2012 |
| Nesheim Privatskole AS | Education | 2014 |
| Netlinq AS | Construction | 2025 |
| Nevro Arendal AS | Health & social care | 2017 |
| New Flavours of India AS | Hospitality | 2014 |
| Next Chapter AS | Professional & scientific | 2026 |
| Nexxtg Holding AS | Real estate | 2021 |
| Nilsen Tv-Service | Construction | 2013 |
| Nilsen Ventilasjon AS | Construction | 2010 |
| Nina Gjertsen Eiendom AS | Real estate | 1989 |
| NK Coaching AS | Education | 2026 |
| No Consulting AS | Professional & scientific | 2014 |
| Nokså Unge Lovende AS | Real estate | 2024 |
| Noraberg & Co AS | | 2025 |
| Norac AS | Wholesale & retail | 1997 |
| Norac Badekabiner AS | Wholesale & retail | 1998 |
| Norcash AS | Wholesale & retail | 2017 |