| Mariannes Brodering AS | Råde | 2016 |
| Mariba AS | Tjøme | 2013 |
| Maribes AS | Oppegård | 2024 |
| Maridalsveien Smådyrklinikk AS | Oslo | 2001 |
| Marie & Co. AS | Oslo | 2024 |
| Marie AS | Naustdal | 2025 |
| Marie Nord AS | Oslo | 2023 |
| Marie Øverby Holding AS | Oslo | 2023 |
| Mariela Invest AS | Oslo | 2025 |
| Marihaug Regnskap AS | Oslo | 2014 |
| Mariko AS | Bergen | 2003 |
| Marin Aqua AS | Trondheim | 2016 |
| Marin Biotech AS | Deknepollen | 2025 |
| Marin Design AS | Kolvereid | 2006 |
| Marin Eiendom AS | Tjørvåg | 2009 |
| Marin Group AS | Gurskøy | 2009 |
| Marin HMS AS | Kristiansand S | 2018 |
| Marin Industri Offshore Engineering AS | Fevik | 2009 |
| Marin Konsulent AS | Flatanger | 2020 |
| Marin Teknikk AS | Gurskøy | 2006 |
| Marin-E AS | Stavanger | 2022 |
| Marin-Ingeniør Limited Nuf | Ølensvåg | 2007 |
| Marin-Innovasjon AS | Fana | 2005 |
| Marina Coast AS | Trondheim | 2004 |
| Marina Harbour Solutions AS | Ørsta | 2024 |
| Marinbiologen AS | Tysværvåg | 2021 |
| Marinbuddy AS | Hosle | 2023 |
| Marine & Cargo Independent Inspection Services AS | Arendal | 2024 |
| Marine & Industriteknikk AS | Breistein | 2017 |
| Marine & Offshore Services AS | Molde | 2010 |
| Marine 03 Consulting AS | Nesøya | 2019 |
| Marine Aqua Solutions AS | Ørsta | 2024 |
| Marine Cluster AS | Trondheim | 2020 |
| Marine Computation Services Kenny Limited | Galway Irland | 2011 |
| Marine Constructions AS | Os | 1992 |
| Marine Consulting AS | Stordal | 2010 |
| Marine Control Concepts Limited | Rg4 6Lu Reading, Berks | 2014 |
| Marine Control Services AS | Drammen | 2001 |
| Marine Design and Consulting AS | Knarrevik | 2014 |
| Marine Drilling AS | Asker | 1988 |
| Marine Electrical Services Ltd | Gb-Aberdeenshire Ab41 9Rf | 2014 |
| Marine Environment AS | Rygge | 2023 |
| Marine Environmental Services Ltd | South Woodford E18 1El England | 2007 |
| Marine Executive Partner AS | Husøysund | 2008 |
| Marine Fuel Services AS | Lysaker | 2017 |
| Marine Geological Assistance | 9820 Merelbeke | 2004 |
| Marine Group AS | Kongshavn | 1995 |
| Marine HPC AS | Hafrsfjord | 2023 |
| Marine Inspeksjon AS | Manger | 2015 |
| Marine Konstruksjoner AS | Kristiansund N | 1980 |
| Marine Lubechart Solutions AS | Kristiansund N | 2018 |
| Marine Manager AS | Torangsvåg | 2018 |
| Marine Multi Consult AS | Farsund | 2017 |
| Marine Norseman AS | Stathelle | 2018 |
| Marine Norway AS | Haugesund | 2011 |
| Marine Optimalisering AS | Rørvik | 2022 |
| Marine Power House AS | Tananger | 2026 |
| Marine Pro AS | Slemmestad | 2017 |
| Marine Project Consult | 5240 Odense Nø | 2012 |
| Marine Prospects AS | Oslo | 2018 |
| Marine Q Brasil Assessoria Comercial Ltda | Br-22.290-160 Botafogo Rio De Janei | 2022 |
| Marine Resources Advisory Team AS | Grimstad | 2014 |
| Marine Robotic Harvest AS | Bø I Vesterålen | 2024 |
| Marine Rådgivningstjenester AS | Ålesund | 1992 |
| Marine Solutions Norway AS | Ulsteinvik | 2023 |
| Marine Spark X AS | Tromsø | 2024 |
| Marine Stabilization Systems AS | Molde | 2021 |
| Marine Stewardship Council (MSC) | London Ec1A 2Dh England | 2021 |
| Marine Support AS | Storebø | 2002 |
| Marine Technology Consulting AS | Rykkinn | 1995 |
| Marine Thermal Energy Solutions AS | Tennfjord | 2026 |
| Marine Turn AS | Os | 2025 |
| Marine Ventures Ltd | Berkshire Rg1 6Ap | 2010 |
| Marine Water Production AS | Oslo | 2019 |
| Marineintegrator AS | Fiskarstrand | 2025 |
| Marinemec Engineering Services Limited | Wa7 3Eh Cheshire | 2016 |
| Marinesanering AS | Drøbak | 2019 |
| Marinescan AS | Paradis | 2013 |
| Marinescope AS | Vear | 2023 |
| Marinewide AS | Tromsø | 2019 |
| Marinex AS | Kragerø | 2011 |
| Marinhub AS | Elnesvågen | 2020 |
| Marinhub Consultants AS | Elnesvågen | 2026 |
| Marini Consulting AS | Lillestrøm | 2023 |
| Marini Invest AS | Fjerdingby | 2023 |
| Marinix Ocean Tech AS | Kristiansand S | 2018 |
| Marinkompetens | Fornebu | 2023 |
| Marint Ressurssenter AS | Ålesund | 2021 |
| Marinus Invest AS | Stavanger | 2020 |
| Marinutra AS | Ålesund | 2011 |
| Marinvernbruket AS | Rolvsøy | 2023 |
| Mario Gärtner | De-01239 Dresden | 2012 |
| Marisan AS | Oslo | 2022 |
| Marissa AS | Rissa | 2021 |
| Marit Bakkli AS | Ler | 2025 |
| Marit Sibbern AS | Revetal | 2006 |
| Maritech Engineering AS | Fredrikstad | 2012 |
| Maritim Kompetanse AS | Blomsterdalen | 2025 |
| Maritim Management AS | Ålesund | 2005 |
| Maritim Research I AS | Ålesund | 2006 |