| Maren Kommuneservice AS | Water & waste | 2001 |
| Maren Miljøservice AS | Water & waste | 2001 |
| Maritime Elektrisk | Manufacturing | 1985 |
| Maritime Equipment Norway AS | Wholesale & retail | 2020 |
| Marna Engineering AS | Professional & scientific | 2011 |
| Marna Motor AS | Manufacturing | 1989 |
| Marnar Brygge AS | Real estate | 2004 |
| Marnar Bygg AS | Construction | 1987 |
| Marnar Eiendom AS | Real estate | 1991 |
| Marnar Elektro AS | Construction | 2021 |
| Marnar Maskinservice AS | Manufacturing | 2024 |
| Marnar Trafikkskole AS | Education | 2020 |
| Marnargården Da | Real estate | 1994 |
| Marnarveien 19/21 AS | Real estate | 2017 |
| Marnaveien 24 Ans | Real estate | 2009 |
| Martin Utvikling AS | Manufacturing | 2005 |
| Matkli Invest AS | Real estate | 2019 |
| Mav Eiendom AS | Real estate | 2006 |
| Max Minilager AS | Real estate | 2024 |
| Maxi AS | Construction | 2024 |
| MB Marine SA | Wholesale & retail | 2021 |
| Mb-Invest AS | Construction | 2005 |
| MBT Vigeland AS | Transport & logistics | 1998 |
| Megimove AS | Education | 2023 |
| Meister Norge AS | Wholesale & retail | 2017 |
| Merlett Nor AS | Wholesale & retail | 1996 |
| Meron Holding AS | Wholesale & retail | 2016 |
| Mestiva AS | Professional & scientific | 2017 |
| MFC Holding AS | | 2009 |
| MG Investments AS | | 2026 |
| Midtmarka AS | Real estate | 2017 |
| Miira Konsult Da | Education | 2025 |
| Mikkelsmyrveien 6 AS | | 2025 |
| Mikkelsmyrveien AS | Real estate | 2005 |
| Mikki AS | | 2024 |
| Milano Mandal AS | | 2024 |
| Milla & Luna's Hundesalong AS | Other services | 2024 |
| Minde Terrasse AS | Real estate | 2005 |
| Mint Branding AS | Wholesale & retail | 2012 |
| Mittertal Invest AS | Real estate | 2021 |
| Mix Mandal AS | Wholesale & retail | 1998 |
| Mjåvann Bolig AS | Real estate | 2017 |
| Mjåvannssvingen 43 AS | | 2026 |
| Mk-Ultra Holding AS | Professional & scientific | 2024 |
| Mkjellby AS | Professional & scientific | 2019 |
| MLK Eiendom AS | Wholesale & retail | 2006 |
| Mones Centeret AS | Wholesale & retail | 1982 |
| Mones Wok & Cafe AS | Hospitality | 2016 |
| Morten Hønneland AS | Administrative & support | 2013 |
| Move on AS | Health & social care | 2017 |
| MR & MRS Johnsen AS | | 2026 |
| MS Ternen Ans | Agriculture & fishing | 1998 |
| MT Mandal AS | | 2020 |
| Mtom AS | Administrative & support | 2013 |
| Muha Holding AS | Real estate | 1984 |
| Muren Holding AS | Professional & scientific | 2018 |
| MVB AS | Administrative & support | 2014 |
| Myntheia Invest AS | | 2023 |
| Myrkraft AS | Financial services | 2005 |
| Marnar Bygg II AS | Real estate | 1988 |
| Mågesteinen AS | Financial services | 2005 |
| Møll Takst AS | Real estate | 2025 |
| Møll Vårdal Invest AS | | 2007 |
| Møller Moulins Vei 9 AS | Real estate | 2022 |
| Mønsås Manuellterapi AS | Health & social care | 2013 |
| Mørch Fysikalske AS | Health & social care | 2015 |
| N.Gormly Services AS | Construction | 2022 |
| Natur-Ligvis AS | Wholesale & retail | 2015 |
| Nautic Eiendom Da | Real estate | 1996 |
| Nautic Holding AS | Wholesale & retail | 2005 |
| Nautic Marine AS | Wholesale & retail | 1996 |
| Neseveien Invest AS | Health & social care | 2019 |
| Nextevent AS | Wholesale & retail | 2018 |
| Nextevent Holding AS | | 2024 |
| NH Invest AS | Real estate | 2005 |
| Nha Holding AS | Arts & recreation | 2019 |
| NHL Invest AS | | 2026 |
| Noddeland & Co AS | Manufacturing | 1997 |
| Noddeland Eiendom AS | Real estate | 2021 |
| Noddeland Maskinering & Prototyp AS | Manufacturing | 2021 |
| Noddeland Modell Og Innredning AS | Manufacturing | 2013 |
| Nodeheia AS | Real estate | 2007 |
| Nomedal Design AS | Professional & scientific | 2012 |
| Nordholmen Eiendom AS | Real estate | 2012 |
| Nordic Polymers AS | Professional & scientific | 1997 |
| Nordic.Venture AS | | 2025 |
| Nordikka AS | Professional & scientific | 2025 |
| Nordskog Skogsvei SA | Real estate | 2010 |
| Nordstranda Marina Da | Wholesale & retail | 1996 |
| Norgesbygg Sør AS | Construction | 2011 |
| Norrøn-Fabrikkutsalg Avd Mandal AS | Wholesale & retail | 1998 |
| Nua AS | Professional & scientific | 1997 |
| Nua Brygghus AS | Manufacturing | 2013 |
| Nunatak Development AS | Professional & scientific | 2013 |
| Nur Arkitekter AS | Professional & scientific | 2026 |
| Nybolig AS | Real estate | 2016 |
| Nye Cactus AS | Wholesale & retail | 1991 |
| Nyera Consulting AS | Professional & scientific | 2025 |
| Nymalt Holding AS | Construction | 2023 |
| Nymalt Mandal AS | Construction | 2023 |