| Aunehaugen Invest AS | | 2025 |
| Aunes Multiservice AS | Construction | 2021 |
| Aunes Oversettelser AS | Professional & scientific | 2002 |
| Auqr AS | Professional & scientific | 2026 |
| Auralis AS | Information & communication | 2025 |
| Auratus Capital AS | Professional & scientific | 2016 |
| Aurelio Clothing AS | Wholesale & retail | 2026 |
| Aureus Invest AS | Real estate | 2012 |
| Aurora Baldershage Barnehage AS | Education | 2022 |
| Aurora Film AS | Information & communication | 2011 |
| Aurora Innovation AS | | 2024 |
| Aurora Nordic Holding AS | | 2025 |
| Aurora Regnbuen Barnehage AS | Education | 2022 |
| Aurora Sluppen Barnehage AS | Education | 2022 |
| Aurora Venture AS | Professional & scientific | 2020 |
| Aursand Holding AS | | 2018 |
| Austeen Invest AS | | 2022 |
| Austerbygda Eiendom AS | Real estate | 2016 |
| Austlund AS | | 2026 |
| Austmann Bryggeri AS | Manufacturing | 2012 |
| Austmo Holding AS | Wholesale & retail | 2024 |
| Austraatt AS | Professional & scientific | 2018 |
| Australian Trading Company AS | Professional & scientific | 2014 |
| Auticon AS | Education | 2008 |
| Auticon Holding AS | | 2015 |
| Auticon R&D AS | Professional & scientific | 2011 |
| Auto 8-8 Witro AS | Wholesale & retail | 1985 |
| Auto Biler 2 AS | Wholesale & retail | 2020 |
| Auto Bruno AS | Other services | 2022 |
| Auto Sportiva AS | Other services | 2008 |
| Auto Syd AS | Wholesale & retail | 2022 |
| Auto-Lia AS | Wholesale & retail | 2020 |
| Autobuddies AS | Wholesale & retail | 2020 |
| Autofisch AS | | 2026 |
| Autoimport Norway AS | Wholesale & retail | 2021 |
| Automatikk-Systemer Ans | Education | 1996 |
| Automatinvest.No AS | Administrative & support | 2012 |
| Autonettverk AS | Wholesale & retail | 2025 |
| Autopi AS | Information & communication | 2025 |
| Autoportal AS | Wholesale & retail | 2017 |
| Autoringen Trøndelag AS | Wholesale & retail | 2021 |
| Autosport AS | Wholesale & retail | 2011 |
| Autostil Da | Wholesale & retail | 2001 |
| Autronica Buyer Norway AS | Wholesale & retail | 2024 |
| Autronica Fire and Security AS | Manufacturing | 1998 |
| Availant AS | Information & communication | 2026 |
| Avance AS | | 2012 |
| Avant Management AS | Real estate | 2004 |
| Avantas Aktiv AS | Education | 2006 |
| Avantas AS | Professional & scientific | 2013 |
| Avantas Drift AS | Administrative & support | 2001 |
| Avantas Prisinnhenter AS | Professional & scientific | 2023 |
| Avenio AS | Professional & scientific | 2026 |
| Aventa AS | | 2021 |
| Avenue Holding AS | | 2022 |
| Avesta Holding AS | Wholesale & retail | 2024 |
| Avesta Tepper AS | Wholesale & retail | 2024 |
| Avfallpro AS | Information & communication | 2025 |
| Avh Invest AS | Information & communication | 2017 |
| Aviba AS | | 2024 |
| Avido Nuf | Professional & scientific | 2011 |
| Aviera Nordic AS | Transport & logistics | 2024 |
| Avitus AS | Real estate | 1993 |
| Avj AS | Real estate | 2020 |
| Avon Live Nidaros AS | Arts & recreation | 2016 |
| Avonlyd AS | Construction | 2007 |
| Avtaleplass AS | Information & communication | 2026 |
| Aware Ness AS | | 2025 |
| Awml Holding AS | Real estate | 2015 |
| Axcenta AS | Professional & scientific | 1996 |
| Axel Bruun Sport AS | Wholesale & retail | 1939 |
| Axel Kristoffersen AS | Professional & scientific | 2007 |
| Axel Kvale AS | Professional & scientific | 2007 |
| Axier AS | Financial services | 2017 |
| Axon Technology AS | Information & communication | 2025 |
| Aluman Trondheim A/S | Construction | 1987 |
| Aøs Finans AS | Construction | 2019 |
| B Bersvendsen AS | Construction | 1991 |
| B Boutique AS | | 2025 |
| B Buan AS | Financial services | 2005 |
| B Finans AS | Wholesale & retail | 1985 |
| B Iversen & Co AS | Transport & logistics | 1986 |
| B Oust AS | Administrative & support | 2013 |
| B&B Gruppen AS | Real estate | 2014 |
| B&M Tech AS | Professional & scientific | 2024 |
| B-Thermiq AS | Construction | 2023 |
| B. Våge Holding AS | | 2025 |
| B.Langen Eiendom AS | Real estate | 2021 |
| B.O.H. Invest AS | Real estate | 2014 |
| B2 Invest AS | | 2022 |
| Baam Holding AS | | 2019 |
| Baard Iversens Veg 4 Eiendom AS | Real estate | 2021 |
| Baasland-Klinikken AS | Health & social care | 2015 |
| Baba Byhaven AS | Hospitality | 2022 |
| Babs Invest AS | | 2020 |
| Backbone Holding AS | Arts & recreation | 2018 |
| Backlund Eiendom AS | Real estate | 2017 |
| Backlund Raschke Eiendom AS | Real estate | 2020 |
| Backyard Block Records AS | Information & communication | 2025 |
| Bad & Peis Expert AS | Construction | 2014 |