| 2 Ponder El AS | Construction | 2017 |
| 3 N Eiendom AS | Real estate | 2011 |
| 3 N Equity AS | Real estate | 2021 |
| 3 N Logistics AS | Wholesale & retail | 2016 |
| 3 N Support AS | Wholesale & retail | 2016 |
| 3 Norske AS | Real estate | 2009 |
| 3 Norske Design Group AS | Professional & scientific | 2013 |
| 3 Norske Handel Og Industri AS | Real estate | 2007 |
| 360 Worldwide Limited Nuf | Administrative & support | 2010 |
| 3D Analyse AS | Information & communication | 2019 |
| 3DFRACTAL AS | Information & communication | 2022 |
| 3M Group Holding AS | | 2025 |
| 3S Salg AS | Wholesale & retail | 2024 |
| A Falkenberg Eftf AS | Wholesale & retail | 1976 |
| A.Joakimsen AS | Professional & scientific | 2026 |
| Aastad Impulssenter AS | Health & social care | 2003 |
| Abb Equity Limited | Administrative & support | 2006 |
| Abc Vidsyn AS | | 2020 |
| Abera AS | Information & communication | 2007 |
| Abico AS | Transport & logistics | 2014 |
| Ac Design AS | Arts & recreation | 2013 |
| Accept Elektro Og Automasjon AS | Construction | 2000 |
| Aco Nordic AS | Wholesale & retail | 2011 |
| Active Profile AS | Wholesale & retail | 2015 |
| Activo Holding AS | Financial services | 2012 |
| Advokat Nadheim AS | Professional & scientific | 1990 |
| Advokatfirmaet Normann & Bjørnsen AS | Professional & scientific | 2013 |
| Advokatfirmaet Torgersen AS | Professional & scientific | 2017 |
| Advokatfirmaet Weiss-Andersen AS | Professional & scientific | 2018 |
| Aed Lease NV | Administrative & support | 2017 |
| Aed Rent NV | Administrative & support | 2017 |
| Aeronaut AS | Real estate | 1987 |
| Af Hæhre & Contur Ans | Construction | 2022 |
| Af Hæhre & Isachsen Ans | Construction | 2020 |
| Af Hæhre Isachsen Contur Ans | Construction | 2023 |
| Ak Holding AS | Education | 2016 |
| Akky AS | Real estate | 2008 |
| Aksjeservice AS | Professional & scientific | 2024 |
| Alexir AS | Information & communication | 2025 |
| Alfa Laval Copenhagen Nuf | Wholesale & retail | 2006 |
| Alfa Laval Nordic AS | Wholesale & retail | 1987 |
| Alfanor 20070 AS | Hospitality | 2020 |
| Alfawiz AS | Information & communication | 2024 |
| Alfimed AS | Wholesale & retail | 2008 |
| Amber PMS AS | Professional & scientific | 1996 |
| Amiata Holding AS | | 2023 |
| Amo AS | Professional & scientific | 1989 |
| Analog Vinter AS | Real estate | 2015 |
| Anders CHR. Bergene AS | | 2000 |
| Anderssen VFP AS | Professional & scientific | 2015 |
| Annshi Holding AS | | 2021 |
| Apecs AS | Wholesale & retail | 2019 |
| Appel Invest AS | Health & social care | 2017 |
| Apprendly AS | Information & communication | 2019 |
| Aprimo Rådgivning Roar Buskoven AS | Professional & scientific | 2021 |
| Aquagain Norge Nuf | Water & waste | 2015 |
| Ariabod AS | Professional & scientific | 2013 |
| Arico AS | Real estate | 2007 |
| Ark AS | Professional & scientific | 2021 |
| Ark Management AS | Professional & scientific | 2022 |
| Artistina Studio AS | Other services | 2004 |
| AS Christiania Glasmagasin | Wholesale & retail | 1986 |
| AS Elje | Manufacturing | 1970 |
| AS Linolim | Real estate | 1934 |
| AS Mime | | 1988 |
| AS Norco-Oslo | Wholesale & retail | 1976 |
| Asker Autospa AS | Other services | 2020 |
| Asker Kvinnehelse AS | Health & social care | 2022 |
| Asp Bygg AS | Construction | 2020 |
| Astracore AS | Real estate | 2026 |
| Ataris Holding AS | Wholesale & retail | 2024 |
| Atent Eiendom AS | Real estate | 2021 |
| Automobil Holding AS | Other services | 2005 |
| Aveng Holding AS | | 2021 |
| Avenue Slependen AS | Other services | 2024 |
| B19 Kontorfellesskap AS | Real estate | 2019 |
| Bache-Gabrielsen Holding AS | Financial services | 2007 |
| Baobab Investments AS | | 2024 |
| Barnematbyen AS | Professional & scientific | 2019 |
| BAUS1 Invest AS | | 2017 |
| BBS Bygg AS | Construction | 2021 |
| Bekkan Capital AS | | 2020 |
| Bell Consulting AS | Professional & scientific | 2015 |
| BELLA90 AS | Financial services | 2005 |
| Beneventum AS | Professional & scientific | 1990 |
| Bepe-Holding AS | Professional & scientific | 1994 |
| Berga Invest AS | | 2020 |
| Bergamini Holding AS | Real estate | 2017 |
| Bergerløkka Parkering AS | Real estate | 2022 |
| Bergerløkka Torg BE11 AS | Real estate | 2025 |
| Bergerløkka Torg BE5 AS | Real estate | 2025 |
| Bergerløkka Torg BE7 AS | Real estate | 2025 |
| Bergmynter Invest AS | | 2021 |
| Bertoia AS | | 2025 |
| Between AS | Information & communication | 2020 |
| BFH AS | Health & social care | 2026 |
| BFM Invest AS | | 2021 |
| Bi Produkter AS Ingeberg | Wholesale & retail | 1983 |
| Bifas AS | Real estate | 1936 |
| Bik Bok AS | Wholesale & retail | 1999 |