| 4 Poter AS | Wholesale & retail | 2013 |
| A C Landgraff AS | Wholesale & retail | 1984 |
| A Og B AS | Construction | 2024 |
| Abarillo AS | Wholesale & retail | 2002 |
| Abe AS | | 2024 |
| Ability AS | Professional & scientific | 2002 |
| Aborr AS | Professional & scientific | 2019 |
| Accurate Too Invest Ltd Nuf | Professional & scientific | 2009 |
| Adaptio AS | Information & communication | 2015 |
| Adev Consult AS | Information & communication | 2022 |
| Adev Invest AS | Information & communication | 2022 |
| Admel Holding AS | Information & communication | 2025 |
| Ael Invest AS | Financial services | 2008 |
| Aemilio AS | | 2023 |
| Aethos AS | Professional & scientific | 2023 |
| Agpt AS | Arts & recreation | 2026 |
| Aguamenti Invest AS | | 2022 |
| Aic Holding AS | Financial services | 1986 |
| Akershus Miljøentreprenør AS | Administrative & support | 1993 |
| Akn Invest AS | | 2020 |
| Aksdal Finans AS | Financial services | 2018 |
| Aktivitets Utleie AS | Administrative & support | 2024 |
| Akvatechnic AS | Professional & scientific | 2025 |
| Albulus AS | Professional & scientific | 2014 |
| Alfafox Invest AS | Real estate | 2018 |
| Alha Holding AS | | 2019 |
| Alkap AS | Professional & scientific | 2015 |
| Alker Aviation AS | Professional & scientific | 2026 |
| Alpha Venturi AS | Administrative & support | 2016 |
| Ambrobygg AS | Construction | 2020 |
| Amstrat AS | Real estate | 2017 |
| Anakena AS | Real estate | 2005 |
| Anders Bolander AS | Professional & scientific | 2003 |
| Andreas Gaarder Holding AS | | 2020 |
| Anis AS | | 2024 |
| Anja Johansen Holding AS | | 2019 |
| Anne Halvorsen Holding AS | Professional & scientific | 2024 |
| Anto Gruppen AS | | 2015 |
| Aponia Holding AS | | 2022 |
| Arctic Advisory AS | Professional & scientific | 2026 |
| Arctic Landscape Hotels AS | Real estate | 2018 |
| Arctic Landscape Hotels Atlanterhavsveien AS | Real estate | 2019 |
| Arctic Landscape Hotels Finnmark Alps AS | Real estate | 2018 |
| Arctic Landscape Hotels Lofoten AS | Real estate | 2019 |
| Arctic Landscape Hotels Vardø AS | Real estate | 2018 |
| Arctic Light AS | Professional & scientific | 2003 |
| Arctic Seeds Invest AS | Construction | 2008 |
| Ardello AS | Information & communication | 2022 |
| Argenti Fodinæ AS | | 2020 |
| Arth. Norderhaug's Eftf. AS | Construction | 2017 |
| Articulus Da | Information & communication | 2014 |
| AS Hind | Real estate | 1991 |
| Ascensio AS | | 2025 |
| Asker & Bærum Bilutleie AS | Administrative & support | 1984 |
| Asker Og Bærum Blåseisolering AS | Construction | 2025 |
| Ateko Invest AS | Real estate | 2012 |
| Atle Walgren AS | Real estate | 2005 |
| Aulix AS | Information & communication | 1998 |
| Aurora Verksted SA | Health & social care | 2000 |
| Awe Invest AS | Financial services | 2015 |
| Baia IV AS | Financial services | 2007 |
| Balta Gruppen AS | Wholesale & retail | 2009 |
| Bare Ben AS | Financial services | 2016 |
| Bedre Kommunikasjon AS | Professional & scientific | 2011 |
| Bedrehjem AS | Real estate | 2018 |
| Bege AS | Financial services | 2014 |
| Bekkestua Rørleggerbedrift AS | Construction | 2025 |
| Bekkestua Transport Og Flytting AS | Transport & logistics | 2024 |
| Bekkestua Venture AS | | 2001 |
| Bekkestua VVS AS | Construction | 2025 |
| Bela Forlag AS | Information & communication | 2023 |
| Bela Invest AS | Professional & scientific | 2006 |
| Bjerkelundsveien 96 Utvikling AS | Real estate | 2019 |
| Board AS | Professional & scientific | 1994 |
| Bofineli AS | Arts & recreation | 2012 |
| Bolivar AS | Real estate | 2004 |
| Breakline AS | Information & communication | 2025 |
| Bright Invest AS | | 2021 |
| Brno AS | Professional & scientific | 2015 |
| Brova Holding AS | Information & communication | 2018 |
| Brova Master AS | Professional & scientific | 2004 |
| Brødrene Nesje AS | Financial services | 2021 |
| Brøtan Invest AS | Financial services | 2016 |
| Bsat Holding AS | Water & waste | 2005 |
| Buck AS | | 1998 |
| Building Supply Consult AS | Construction | 2003 |
| Building Supply Consult Holding AS | Construction | 2003 |
| Buildr AS | Information & communication | 2025 |
| Byggpleie AS | Administrative & support | 2026 |
| Bærum Bad Og Boligrenovering AS | Construction | 2025 |
| Bærum Bilutleie AS | Administrative & support | 1980 |
| Bærum Elektro Team AS | Construction | 2017 |
| Bærum Kranservice AS | Transport & logistics | 2004 |
| Bærum Psykomotoriske Fysioterapi Da | Health & social care | 2019 |
| Bærum Septik Og Transportforretning AS | Water & waste | 1965 |
| Børgefjell Holding AS | | 2024 |
| Campv AS | | 2021 |
| Cape May AS | | 2021 |
| Cardiomyocyte AS | Health & social care | 2021 |
| Carl Holding AS | Administrative & support | 2023 |