| 123VINDUSPUSS AS | Administrative & support | 2018 |
| 3M Butikkdrift AS | Wholesale & retail | 2017 |
| 3M Eiendom AS | Real estate | 2014 |
| 3M Holding AS | Real estate | 2012 |
| A Autopark AS | Wholesale & retail | 2017 |
| Aaaiar Vest AS | Hospitality | 2019 |
| Aamli Consulting AS | Administrative & support | 2026 |
| Aamli Holding AS | | 2025 |
| Aarholt-Tunet AS | Hospitality | 2015 |
| Abf Holding AS | Wholesale & retail | 2024 |
| Academy of Safety and Environmental Studies AS | Professional & scientific | 2022 |
| Acph AS | Real estate | 2017 |
| Advitech AS | Information & communication | 2021 |
| Agripa Norge AS | Wholesale & retail | 2004 |
| Agripa Prosjekt AS | Wholesale & retail | 2018 |
| Ags Group AS | Construction | 2024 |
| Aguilar AS | | 2005 |
| Aiwell AS | Manufacturing | 1997 |
| Aiwell Eiendom AS | Real estate | 2012 |
| Aiwell Holding AS | Manufacturing | 2005 |
| Aiwell Water AS | Professional & scientific | 2016 |
| Ajl Drift AS | Professional & scientific | 2026 |
| Ajl Invest AS | | 2022 |
| Ake Holding AS | Financial services | 2005 |
| Akersvannet Grunneierlag SA | Real estate | 1965 |
| Aksjespareklubben Vip Club AS | Financial services | 2017 |
| Alles Gruppen AS | Real estate | 1998 |
| Alles Miljø AS | Wholesale & retail | 2005 |
| Alles Utleie AS | Administrative & support | 2023 |
| Allteck AS | Administrative & support | 2023 |
| Almek Hydraulic Services AS | Manufacturing | 1999 |
| Almenning Bygg AS | Construction | 2015 |
| Alpha Studio AS | Other services | 2020 |
| Also | Wholesale & retail | 2007 |
| Also AS | Wholesale & retail | 1986 |
| Aluteknikk AS | Wholesale & retail | 2024 |
| Andebuveien 802 AS | Real estate | 2017 |
| Anders Lie Invest AS | Real estate | 2024 |
| Anders Standal Holding AS | | 2022 |
| Andersen & Knoph AS | Construction | 2015 |
| Anholttoppen Invest AS | Financial services | 2014 |
| Anmorts Verden AS | Wholesale & retail | 2010 |
| Antons Vedbu AS | Agriculture & fishing | 2011 |
| Antonsen Transportservice AS | Transport & logistics | 2015 |
| Arild Vedvik Kran & Transport AS | Transport & logistics | 1999 |
| Arnadal Anlegg AS | Construction | 2012 |
| Arnadal Holding AS | Construction | 2020 |
| Arnadal Utvikling AS | Real estate | 2008 |
| Arne Moe Invest AS | Real estate | 1994 |
| Arrow Holding AS | | 2021 |
| Arti Bygg AS | Construction | 2022 |
| AS Billie Holding | Construction | 2022 |
| AS Fellesbygg | Households | 1953 |
| AS Stall Ac | Real estate | 2015 |
| AS Vika Finans | Real estate | 1991 |
| Askerød Samdrift Da | Agriculture & fishing | 2021 |
| Askjem Bobilformidling AS | Wholesale & retail | 2024 |
| At Ease AS | Health & social care | 2023 |
| At-Bygg AS | Construction | 2018 |
| Auchet Holding AS | | 2026 |
| Audber Holding AS | Wholesale & retail | 2020 |
| Audex AS | Professional & scientific | 2024 |
| Audiopedagog Grønsund AS | Health & social care | 2019 |
| Auto X Global AS | Wholesale & retail | 2025 |
| Averion Sør Øst AS | Professional & scientific | 2012 |
| Avkt Holding AS | | 2025 |
| B. Gjein Invest AS | Mining & quarrying | 2005 |
| Bacas AS | Construction | 2002 |
| Bacas Holding AS | Construction | 2021 |
| Balder Eiendom AS | Construction | 2002 |
| Balder Holding AS | | 2018 |
| Baldevin Invest AS | Professional & scientific | 2015 |
| Bear AS | Professional & scientific | 2004 |
| Bedriftsutvikleren AS | Professional & scientific | 2014 |
| Bee My Honey AS | Agriculture & fishing | 2021 |
| Bekkro Holding AS | | 2026 |
| Belesta Holding AS | | 2020 |
| Bergans Mekanikk AS | Manufacturing | 2007 |
| Bergsholm Holding AS | | 2022 |
| Besstek AS | Manufacturing | 1947 |
| Betlehem Forlag AS | Information & communication | 2022 |
| Bettum Hagebruk AS | Agriculture & fishing | 2026 |
| Bilbane Holding AS | | 2013 |
| BILDRIFT1 AS | Other services | 2020 |
| Biltorget Fleet AS | Wholesale & retail | 2022 |
| Birk Holding AS | | 2020 |
| Birkelund & Sommerstad AS | | 1997 |
| Bjerckebo AS | Professional & scientific | 2024 |
| Bjerkely Drift AS | Construction | 2015 |
| Bjørgengen Logopedi AS | Health & social care | 2025 |
| Bjørn a Borgen AS | Financial services | 2005 |
| Bjørn Gustavsen Økonomi Og Regnskap AS | Professional & scientific | 2002 |
| Bjørnb Holding AS | Information & communication | 2005 |
| Blomstersenteret Vestfold AS | Real estate | 2000 |
| Bmbg Invest AS | Construction | 2019 |
| Boatsupply AS | Wholesale & retail | 2017 |
| Boatsupply Invest AS | Real estate | 2020 |
| Boblemost AS | Wholesale & retail | 2017 |
| Bodiva AS | Information & communication | 2021 |
| Bogen Båthavn SA | Arts & recreation | 1968 |