| 2A Stangnes AS | Real estate | 2007 |
| 360 Eiendom AS | Wholesale & retail | 2019 |
| 365 Utleie AS | Administrative & support | 2026 |
| 3D Bygg Og Tegning AS | Construction | 2022 |
| 68 Grader Arctic Service AS | Construction | 2022 |
| A-Bolig AS | Construction | 2022 |
| A. Jørgensen Invest AS | Health & social care | 2025 |
| A.Dahlberg Holding AS | | 2026 |
| A3 Eiendom AS | Real estate | 2013 |
| Aaf Consulting&Investing AS | Professional & scientific | 2022 |
| Aarvak Invest AS | | 2026 |
| Aboutme Productions AS | Information & communication | 2008 |
| Abrams AS | | 2024 |
| Ac Designtech AS | Professional & scientific | 2003 |
| Acuro AS | Health & social care | 2013 |
| Administrasjonen AS | Real estate | 2018 |
| Advokatfirma Ovesen Da | Professional & scientific | 2008 |
| Advokatfirmaet Finn AS | Professional & scientific | 2007 |
| Advokatfirmaet Jørstad AS | Professional & scientific | 2017 |
| Advokatfirmaet Stenstrøm AS | Professional & scientific | 2021 |
| Advokathuset Harstad AS | Professional & scientific | 2013 |
| Ae Elektro AS | Construction | 2010 |
| Aeh Bolig AS | Real estate | 2023 |
| Ag-Bygg AS | Construction | 2025 |
| Ag-Trapp AS | Construction | 2026 |
| Agalas Cable 1 AS | Transport & logistics | 2021 |
| Agalas Energy Holding III AS | Transport & logistics | 2025 |
| Agalas Energy II Holding AS | Transport & logistics | 2023 |
| Agalas Holding AS | Transport & logistics | 2021 |
| Agalas Management AS | Professional & scientific | 2023 |
| Aggregatservice AS | Construction | 2024 |
| Agropartner Pro AS | Transport & logistics | 2024 |
| Aiteall Holding AS | | 2020 |
| Aivos AS | Information & communication | 2026 |
| Aj Klima II AS | Construction | 2025 |
| Ajb Gruppen AS | Financial services | 2005 |
| Ajla Holding AS | Construction | 2019 |
| Ajm Holding AS | | 2005 |
| Ak Henriksen Eiendom AS | Real estate | 2022 |
| Akse Eiendom AS | Real estate | 2006 |
| Aksjeeieren AS | Professional & scientific | 2016 |
| Alf B Holding AS | | 2005 |
| Alfa Internsystemer AS | Professional & scientific | 1988 |
| Alfred Surgery AS | Professional & scientific | 2016 |
| Alkeveien 7 AS | Real estate | 1979 |
| Alltakst AS | Professional & scientific | 2012 |
| Altaelva AS | Real estate | 2015 |
| Altibygg AS | Construction | 1992 |
| Altipluss AS | Professional & scientific | 1991 |
| Altura Holding AS | Real estate | 2020 |
| Alv Ervik Transport AS | Transport & logistics | 2002 |
| Amedia Ressurs Harstad AS | Professional & scientific | 1996 |
| Ameno Net Da | Information & communication | 2000 |
| Amn AS | Real estate | 2022 |
| Amors Biler AS | Administrative & support | 2013 |
| Amundsen Transport AS | Transport & logistics | 2014 |
| An-Holding AS | Other services | 2013 |
| Andersen Rør AS | Construction | 1998 |
| Andrik AS | Real estate | 1980 |
| Andselv Næringstomt AS | Real estate | 2015 |
| Anew Branding AS | Professional & scientific | 2006 |
| Anleggsdrift Harstad AS | Construction | 2014 |
| Ans Strandgt 15 Harstad | Real estate | 1983 |
| Ans Te Og Trivsel | Wholesale & retail | 1987 |
| Ans Uni-Video | Administrative & support | 1988 |
| Ans Videoforum Harstad | Administrative & support | 1988 |
| Ans Wenche Og Eirin | Wholesale & retail | 1989 |
| Antonsens Radioservice AS | Wholesale & retail | 1998 |
| Ao Maling Og Vedlikehold AS | Administrative & support | 2011 |
| Apartof AS | Real estate | 2005 |
| Apotekergården Eiendom AS | Real estate | 2013 |
| Apro Harstad AS | Administrative & support | 2015 |
| Ar Æsthetic AS | Health & social care | 2023 |
| Arctic Base Holding AS | Information & communication | 2012 |
| Arctic Care AS | Manufacturing | 2011 |
| Arctic Eiendom Harstad AS | Real estate | 2015 |
| Arctic Grill & Bar AS | Hospitality | 2026 |
| Arctic Image AS | Professional & scientific | 1998 |
| Arctic Insights Tromsø AS | Administrative & support | 2024 |
| Arctic Living AS | Professional & scientific | 2002 |
| Arctic Lobster Farm AS | Agriculture & fishing | 2025 |
| Arctic Loot AS | Wholesale & retail | 2026 |
| Arctic Mobility AS | Transport & logistics | 2025 |
| Arctic Origins AS | Mining & quarrying | 2014 |
| Arctic R&B AS | Real estate | 2017 |
| Arctic Race of Norway AS | Arts & recreation | 2013 |
| Arctic Regnskap AS | Professional & scientific | 2008 |
| Arctic Seafood Center AS | | 2011 |
| Arctic Sport AS | Arts & recreation | 2009 |
| Arctic Stick on Stage AS | Professional & scientific | 2018 |
| Arctic Tide AS | Hospitality | 2025 |
| Arctic Well Invest AS | Professional & scientific | 2016 |
| Arena Larsneset AS | Real estate | 2021 |
| Arena Larsneset Drift AS | Real estate | 2022 |
| Argos Holding AS | | 2017 |
| Arh Holding AS | | 2008 |
| Arild Hansens Vaktmestertjeneste AS | Administrative & support | 2013 |
| Arktiske Hager AS | Real estate | 2013 |
| Arktix Dialog AS | Administrative & support | 2026 |
| Arne Isaksen Holding AS | | 2026 |