| 1-2-TRE AS | Construction | 1985 |
| 2PLAN Bygg AS | Construction | 2012 |
| 365 Østfold AS | Information & communication | 2026 |
| 3G Eiendom AS | Real estate | 2008 |
| A&M Eiendom AS | Real estate | 1972 |
| A&M Maskin AS | Wholesale & retail | 2019 |
| A.V.S Invest AS | | 2021 |
| A1 Fredrikstad Eiendomstaksering AS | Real estate | 2008 |
| Abh Invest AS | Administrative & support | 2020 |
| Ac Rosenberg AS | Professional & scientific | 2013 |
| Acinor AS | Manufacturing | 2002 |
| Adamek Bygg AS | Construction | 2018 |
| Adaptiq AS | Information & communication | 2019 |
| Adesso Bioproducts AS | Manufacturing | 2015 |
| Afi Vann Og Varme AS | Construction | 2013 |
| Agmo Holding AS | Wholesale & retail | 2015 |
| Agrotech Production AS | Wholesale & retail | 2011 |
| Ah Capital AS | Construction | 2020 |
| Ak Bygg Og Eiendom AS | Real estate | 2007 |
| Ak Gruppen AS | Manufacturing | 2011 |
| Ak Kran Og Transport AS | Administrative & support | 2006 |
| Ak Mekaniske AS | Manufacturing | 2001 |
| Ak Totalbygg AS | Construction | 2026 |
| Akinom AS | Administrative & support | 1996 |
| Akreyi Vekst & Invest | | 2024 |
| Akreyi Vekst & Invest Holding | | 2024 |
| Aktiv Ressurs AS | Real estate | 1995 |
| Altitec.No AS | Wholesale & retail | 2021 |
| Aluglass Consulting AS | Professional & scientific | 2024 |
| Amok Equipment AS | Wholesale & retail | 2013 |
| Amp AS | Administrative & support | 2015 |
| Amundsen Eiendom AS | Real estate | 2001 |
| Anbesa Holding AS | | 2026 |
| Ande Holding AS | | 2024 |
| Andersen & Mørck AS | Transport & logistics | 2014 |
| Andersen & Mørck Holding AS | Transport & logistics | 1983 |
| Anestesi Support AS | Health & social care | 2016 |
| Anonsen Eiendom AS | Real estate | 2022 |
| Antennemaller AS | Agriculture & fishing | 2015 |
| Antonsen AS | Arts & recreation | 2021 |
| Anubis Holding AS | Real estate | 2015 |
| Aqua VVS AS | Construction | 2025 |
| Aqua VVS Invest AS | | 2025 |
| Arenasystemer AS | Construction | 2012 |
| Arildsborg AS | Real estate | 2011 |
| Arne Svendsensgate 4 AS | Real estate | 2018 |
| Arnes Eiendom AS | Transport & logistics | 2022 |
| Art Ranger AS | Wholesale & retail | 2024 |
| AS Batteriretur | Wholesale & retail | 1993 |
| AS Bjørnegården | Real estate | 1965 |
| AS Gudeberg Boligselskap 1 | Households | 1947 |
| AS In-A-Vision | Information & communication | 2019 |
| AS Resell Design | Professional & scientific | 1986 |
| Askheim AS | Professional & scientific | 2014 |
| Aurelia Wines AS | Wholesale & retail | 2026 |
| Autopleie AS | Wholesale & retail | 2026 |
| Avantiz AS | Wholesale & retail | 1996 |
| Averis AS | Professional & scientific | 2012 |
| Avitel Eiendom AS | | 2013 |
| Axora AS | Administrative & support | 2025 |
| Azur Investments AS | Real estate | 2025 |
| B-Ks AS | Professional & scientific | 2010 |
| B.S Bygg AS | Construction | 2024 |
| B17 Invest AS | Information & communication | 2024 |
| Backe Østfold AS | Construction | 1998 |
| Backstage Kommunikasjon AS | Professional & scientific | 2022 |
| Balaklava Eiendom AS | Real estate | 1993 |
| Balar Invest AS | Information & communication | 2005 |
| Bamse Produkter AS | Health & social care | 2008 |
| Barken AS | Professional & scientific | 2014 |
| Batteriretur Ev AS | Water & waste | 2014 |
| Battery Operations Norway AS | Water & waste | 2019 |
| Be Assets AS | Real estate | 2001 |
| Be Group AS | Real estate | 2021 |
| Beautiful Minds AS | Professional & scientific | 2000 |
| Beer Sten AS | Wholesale & retail | 1989 |
| Begby Elektriske AS | Construction | 1998 |
| Begby Gatekjøkken AS | Hospitality | 2013 |
| Begby Gård AS | Real estate | 2020 |
| Begbyenga Barnehage AS | Education | 2022 |
| Berghelgesen AS | | 2025 |
| Bernt Magnussen Holding AS | Financial services | 2013 |
| Betto AS | Real estate | 2014 |
| Betto Invest AS | Real estate | 2019 |
| Bevi Holding AS | Professional & scientific | 2018 |
| Bevøfestivalen AS | Arts & recreation | 2025 |
| Bevøkiosken Ans | | 1994 |
| BHW Invest AS | Real estate | 2006 |
| Bikuben Design & Produksjon AS | Information & communication | 2024 |
| Bilet Invest AS | Real estate | 2007 |
| Bjarne Og Jon-Anders Larsen Eiendom Da | Real estate | 2001 |
| BK Hengeren AS | Manufacturing | 2016 |
| BK Logistics AS | Transport & logistics | 2014 |
| Bkvent AS | Construction | 2005 |
| Bliss Era Holding AS | Other services | 2026 |
| Bliss Era Studio Oslo AS | Other services | 2026 |
| Bloksberg Invest AS | Real estate | 1997 |
| Blåfjelldal IT AS | Information & communication | 2019 |
| BM Aquaculture AS | Professional & scientific | 2014 |
| Bodahl-Johansen Holding AS | Real estate | 2025 |