| Matglede Lørenskog AS | Wholesale & retail | 2023 |
| Mats Som Designer AS | Professional & scientific | 2022 |
| Max Auto AS | Wholesale & retail | 2014 |
| Max Byggservice AS | Construction | 2022 |
| MD Prime AS | Health & social care | 2026 |
| MDS Malerentreprenør AS | Construction | 2018 |
| Meatbox AS | Wholesale & retail | 2025 |
| Medcap AS | Health & social care | 2026 |
| Media Entertainment AS | Professional & scientific | 2009 |
| Mega Fun AS | Arts & recreation | 2014 |
| Megabyte Ans | | 1997 |
| Mehler Holding AS | | 2025 |
| Mekanikk Og Elektroservice AS | Manufacturing | 2012 |
| Mel Asker 5 AS | Real estate | 2024 |
| Mel Heia 17 AS | Real estate | 2022 |
| Mel Heia 33 AS | Real estate | 2022 |
| Mel Heia 40 AS | Real estate | 2022 |
| Melina Is AS | Wholesale & retail | 2020 |
| Mellebygg AS | Construction | 2005 |
| Mellem Og Martinsen AS | Construction | 1974 |
| Mellqvist Consulting AS | Information & communication | 2014 |
| Melsnes Assuranse AS | Financial services | 2012 |
| Memo Elektro AS | Construction | 2003 |
| Memo Elektro Kommunikasjon AS | Construction | 2010 |
| Memo Elservice AS | Construction | 2012 |
| Memo Holding AS | | 2005 |
| Meras Invest a AS | Financial services | 2021 |
| Meras Invest M AS | Financial services | 2021 |
| Meras Invest R AS | Financial services | 2021 |
| Meras Invest S AS | Financial services | 2021 |
| Merelektro AS | Construction | 2016 |
| Messeprodukter AS | Professional & scientific | 1995 |
| Mesterbygg AS | Construction | 1997 |
| Meta Jscf AS | Wholesale & retail | 2019 |
| Metro Flyttebyrå Avd Oslo AS | Transport & logistics | 2024 |
| Metro Helsoteket AS | Wholesale & retail | 2000 |
| Metro Skårer Specsavers AS | Wholesale & retail | 2013 |
| Metro Trafikkskole AS | Education | 1996 |
| Metro Ur Og Smykker AS | Wholesale & retail | 2007 |
| Mettes Engros AS | Wholesale & retail | 1994 |
| MG Cafehub AS | Hospitality | 2026 |
| MG Kapital AS | Education | 2023 |
| Mi Transport Da | Transport & logistics | 2010 |
| Mia Makeup AS | Wholesale & retail | 2025 |
| Micos Analyse Og Rådgivning AS | Professional & scientific | 2013 |
| Micro Drift AS | Administrative & support | 2012 |
| Micronet AS | Information & communication | 2006 |
| Mik Renhold Service AS | Administrative & support | 2016 |
| Mikel Holding AS | | 2026 |
| Min Verdivurdering AS | Education | 2024 |
| Miran Gruppen AS | | 2026 |
| Mirza Invest AS | Real estate | 2018 |
| Mission for Christ | Other services | 2004 |
| Miu Holding AS | | 2026 |
| MJN Holding AS | | 2022 |
| MJT Invest AS | Financial services | 2015 |
| Mjøspanorama Hytter AS | Hospitality | 2022 |
| MKM Capital AS | Construction | 2025 |
| MM Capital AS | | 2026 |
| MM Capital Invest AS | Professional & scientific | 2018 |
| Mma Invest AS | Financial services | 2010 |
| Molden Invest AS | Transport & logistics | 2017 |
| Moments Climbing Norway AS | Arts & recreation | 2019 |
| Monteiro Invest AS | | 2024 |
| Morgan Security Services Nuf | Professional & scientific | 2009 |
| Morten Pettersen AS | Health & social care | 2013 |
| Morten Stie AS | Real estate | 2005 |
| Morten Sørli Holding AS | Manufacturing | 2005 |
| Mortens Rør Og Vedlikehold AS | Construction | 2018 |
| Mostue Transport AS | Transport & logistics | 2026 |
| Move 24-7 Transport AS | Transport & logistics | 2018 |
| Move Kiropraktikk AS | Health & social care | 2013 |
| Mpe Holding AS | Financial services | 2013 |
| MRV Holding AS | | 2025 |
| MSF Invest AS | Real estate | 2021 |
| Mucha Dental AS | Health & social care | 2022 |
| Muskel Gruppen AS | Education | 2023 |
| Møbelringen Lørenskog AS | Wholesale & retail | 2009 |
| N Jacobsens Karosserifabrikk AS | Manufacturing | 2003 |
| Nane AS | Information & communication | 2022 |
| Naustrom Holding AS | | 2025 |
| Neatech AS | Wholesale & retail | 2014 |
| Nebrox AS | Health & social care | 2025 |
| Nedre Romerike Eiendom AS | Transport & logistics | 2001 |
| Nedre Romerike Invest 2 AS | | 2025 |
| Nedre Romerike Invest AS | Transport & logistics | 2005 |
| Nedre Romerike Minibuss AS | Transport & logistics | 1994 |
| Neebi AS | Hospitality | 2022 |
| Nek Kabel AS | Wholesale & retail | 1998 |
| Nero Entreprenør AS | Construction | 2020 |
| Nesåssetra Holding AS | Financial services | 2014 |
| Netthandelshuset AS | Wholesale & retail | 2025 |
| Neu AS | Construction | 2019 |
| Nexa AS | Professional & scientific | 2025 |
| Nicolaisen Holding AS | | 1993 |
| Nikra AS | Administrative & support | 2016 |
| Nils Hansensvei 9 - 11 AS | Real estate | 2018 |
| Nitor AS | Health & social care | 2003 |
| Nitor Novum AS | Health & social care | 2022 |
| Nitor Opus AS | Health & social care | 2017 |