| Larsen Blikkenslagerverksted AS | Construction | 2008 |
| Larsen Bygg Og Anlegg AS | Construction | 2018 |
| Larssen Capital AS | Financial services | 2005 |
| Lashes by Mea AS | Other services | 2024 |
| Lba Eiendom AS | Real estate | 2013 |
| Lba Holding AS | Construction | 2018 |
| LBL Eiendom Invest AS | Real estate | 2017 |
| LBT Nord AS | Construction | 2024 |
| LC Utleie AS | Administrative & support | 2023 |
| Lcbn Invest AS | | 2025 |
| LDB Holding AS | Wholesale & retail | 2016 |
| Ledsystems AS | Wholesale & retail | 2005 |
| Leieco AS | Administrative & support | 2023 |
| Leon Sport AS | Wholesale & retail | 2014 |
| Lerdahl Consult AS | Professional & scientific | 2015 |
| Lettare Liv AS | Administrative & support | 2019 |
| Liane Holding AS | Health & social care | 2020 |
| Lihan AS | | 2015 |
| Liholt AS | Financial services | 2005 |
| Lileng AS | Wholesale & retail | 2003 |
| Liljen AS | Health & social care | 2006 |
| Limo-Med AS | Health & social care | 1988 |
| Lind Eiendom AS | Real estate | 1997 |
| Linds Agenturer AS | Hospitality | 1995 |
| Lindøy Holding AS | Administrative & support | 2025 |
| Lisa Skarsem AS | Other services | 2019 |
| Live IT AS | Education | 2015 |
| Liøybygg AS | Construction | 2013 |
| LL Eiendom Harstad AS | Real estate | 2015 |
| LL Holding Harstad AS | Real estate | 2019 |
| Lofoten AS | Real estate | 2005 |
| Lofotporten Holding AS | Real estate | 2005 |
| Lorry Scene & Event AS | Hospitality | 2023 |
| LRL Property AS | Real estate | 2024 |
| LRS Bygg Og Eiendom AS | Real estate | 2008 |
| LSG Holding AS | Agriculture & fishing | 2023 |
| LTN Eiendom Harstad AS | Real estate | 2026 |
| LTN Holding AS | | 2026 |
| Lukas Gjertsen Dagligvare AS | Wholesale & retail | 2026 |
| Lundecon Bygg AS | Construction | 2023 |
| Lundecon Oü | Construction | 2021 |
| Lyngvær Invest AS | Hospitality | 2022 |
| Lys I Nord AS | Wholesale & retail | 2013 |
| Lysplan AS | Professional & scientific | 2017 |
| Låsemannen AS | Financial services | 2017 |
| Løtveit Fysioterapi AS | Health & social care | 2006 |
| M Johnsen Tjenester AS | Agriculture & fishing | 2014 |
| M.Hind Holding AS | | 2026 |
| M.T.S. Invest AS | Real estate | 2016 |
| M2-UTLEIE AS | Real estate | 2022 |
| Ma-Jo AS | Wholesale & retail | 2012 |
| Macer Eiendom AS | Real estate | 2024 |
| Macer Holding AS | Wholesale & retail | 2024 |
| Magnira AS | Wholesale & retail | 2025 |
| Magnusgate Eiendom AS | Real estate | 2007 |
| Mak Invest AS | | 2024 |
| Makap AS | | 2021 |
| Malermester Kjernåsen AS | Construction | 2021 |
| Malersentralen AS | Construction | 2006 |
| Malersentralen Eiendom AS | Real estate | 2020 |
| Malersentralen Holding AS | Real estate | 2020 |
| Mama Rosa Pizzeria Ans | Hospitality | 2004 |
| Manoda AS | Manufacturing | 2000 |
| Margrethe Jørgensens Vei 2 AS | Real estate | 1990 |
| Marianker AS | Health & social care | 2010 |
| Marianker Eiendom AS | Health & social care | 2012 |
| Marios Musikk AS | Wholesale & retail | 1990 |
| Maritha Jensa AS | | 2022 |
| Markussen Holding AS | Real estate | 2010 |
| Martin Hokland AS | Real estate | 2017 |
| Martin Tollefsen AS | | 2026 |
| Maryann Risbøl AS | Other services | 2022 |
| Marylou Holding AS | Financial services | 2013 |
| Maskin I Nord AS | Construction | 2017 |
| Massasjeterapeut Jani Pyykkö AS | Other services | 2015 |
| Massasjeterapeut Siv Eilertsen AS | Other services | 2019 |
| Mataks Holding AS | Administrative & support | 2024 |
| Mathiassen Bil AS | Real estate | 2013 |
| Mathiassen Eiendom Andøy AS | Real estate | 2012 |
| Mathiassen Invest AS | Real estate | 2010 |
| Mathiassen Invest Holding AS | Real estate | 2020 |
| Matvaretrygghet AS | Professional & scientific | 2022 |
| Maws Holding AS | Real estate | 2026 |
| Mdreyer Holding AS | | 2023 |
| Mea Investeringer AS | | 2023 |
| Medibrix Ansatt Invest AS | Wholesale & retail | 2023 |
| Medibrix AS | Information & communication | 2013 |
| Medibrix Holding AS | Wholesale & retail | 2023 |
| Medkila Boligpark AS | Real estate | 2022 |
| Medkila Eiendom AS | Real estate | 2013 |
| Medkila Fotballpark AS | Real estate | 2007 |
| Medkila Nord AS | Real estate | 2012 |
| Medkila Tomteselskap AS | Real estate | 2022 |
| Medkila Utvikling AS | Real estate | 2024 |
| Meike & Kent AS | Professional & scientific | 2014 |
| Mejland Invest AS | | 2025 |
| Melvik Industrieiendom AS | Real estate | 2022 |
| Mercurveien 31 AS | Real estate | 2025 |
| Merkantil Service Harstad AS | Professional & scientific | 1990 |
| Mevako Management AS | | 2019 |