| André-Dekk AS | Wholesale & retail | 2001 |
| Anillaveien 25 AS | | 2020 |
| Aninin Holding AS | Real estate | 2014 |
| Anker Kompositt AS | Administrative & support | 2025 |
| Anl Holding AS | | 2024 |
| Anlegg-Og Miljøservice AS | Manufacturing | 2003 |
| Annen Etasje Legesenter Da | Health & social care | 2004 |
| Annik AS | Professional & scientific | 2026 |
| Anord Invest AS | Real estate | 2015 |
| Ans Pindsle Og Evensen Interiørservice | | 1988 |
| Ansa Investment AS | Real estate | 2019 |
| Ansatt VKV AS | | 2023 |
| Antfarm AS | Information & communication | 2022 |
| Aperia AS | Information & communication | 1994 |
| Apiro AS | Information & communication | 2023 |
| Apollo Hårsenter Sandefjord AS | Other services | 1998 |
| Apollon & Afrodite AS | Wholesale & retail | 1996 |
| Apotekergården AS | Real estate | 2006 |
| Aqwa AS | Professional & scientific | 2012 |
| Aralt Holding AS | Wholesale & retail | 2013 |
| Aralt Retail AS | Wholesale & retail | 2015 |
| Arander AS | Wholesale & retail | 2024 |
| Arbeidsvarsling AS | Construction | 2025 |
| Arc AS | Professional & scientific | 1993 |
| Arctic Approach Management AS | Arts & recreation | 2023 |
| Arctos AS | Real estate | 2022 |
| Are Austnes AS | Health & social care | 2005 |
| Arebo AS | Real estate | 1983 |
| Areka Kompetanse AS | Information & communication | 1998 |
| Arena Forlag AS | | 2005 |
| Arena Næring AS | Real estate | 2010 |
| Arena-Ikt Da | Information & communication | 2007 |
| Arezasto AS | Health & social care | 2014 |
| Arild Karlsen Eiendom AS | Real estate | 2017 |
| Aringberg AS | Information & communication | 2019 |
| Arkas AS | Administrative & support | 2006 |
| Arken Bygg AS | Construction | 2019 |
| Armando Bygg AS | Construction | 2021 |
| Arne Andresen AS | Wholesale & retail | 1993 |
| Arne Rød Holding AS | Construction | 2023 |
| Arnulf Andersen AS | Construction | 2021 |
| Arrow-Norway AS | Construction | 2023 |
| Arthur Strand AS | Real estate | 1976 |
| Artic Lines AS | Transport & logistics | 2026 |
| Artilogix AS | Information & communication | 2026 |
| Artyfy Event AS | Arts & recreation | 2020 |
| Arve Karlsen AS | Wholesale & retail | 1995 |
| Arvesen Eiendom AS | Real estate | 2000 |
| Arvid H Holding AS | | 2019 |
| AS Aagaarden | Other services | 1949 |
| AS Aviemore | Real estate | 1987 |
| AS Cleaningshop.No | Wholesale & retail | 1999 |
| AS Fjellveien 2 | Households | 1955 |
| AS Hegnabygg | Real estate | 1980 |
| AS Kilgaten 8 | Real estate | 1984 |
| AS Klavenessbygg | Real estate | 1981 |
| AS Ressursutvikling | Professional & scientific | 1991 |
| AS Thor Dahl | Real estate | 1920 |
| AS Trikker'N | Professional & scientific | 2017 |
| Asalo AS | | 2025 |
| Asas Sertifisering AS | Professional & scientific | 1997 |
| Asbjørn Magnus Bergtun AS | Real estate | 1981 |
| Ascabe AS | Information & communication | 2021 |
| Asciano Invest AS | Professional & scientific | 2007 |
| Asfaltfeiing AS | Administrative & support | 2026 |
| Ash Utleie & Invest AS | Administrative & support | 2026 |
| Asia Mat Sandefjord AS | Wholesale & retail | 2020 |
| Asiahallen Sandefjord AS | Wholesale & retail | 2025 |
| Asiamark Sandefjord AS | Wholesale & retail | 2026 |
| Asker Distribusjon Og Transport AS | Transport & logistics | 2025 |
| Asnes Holding AS | Education | 2021 |
| Aspire Nordic Holding AS | Real estate | 2025 |
| Assistly AS | Administrative & support | 2018 |
| Astria Systems AS | Information & communication | 2025 |
| Astrømøy Invest AS | | 2022 |
| At-Mur AS | Construction | 2018 |
| Atb Invest AS | Real estate | 2005 |
| Ath Eiendom AS | | 2006 |
| Athene Invest AS | Hospitality | 1999 |
| Athene Invest Holding AS | Hospitality | 2023 |
| Atlantic Selskapslokaler AS | Hospitality | 2009 |
| Atlas Laserklinikk AS | Health & social care | 2017 |
| Atle Larsen Holding AS | Construction | 2024 |
| Attitude Pole Studio AS | Education | 2024 |
| AU79 Group AS | Professional & scientific | 2005 |
| Audacious Eiendom AS | Real estate | 2021 |
| Audacious-Holding AS | Real estate | 2021 |
| Augere AS | Health & social care | 2025 |
| August Holding AS | Real estate | 2008 |
| Aulie Elektro AS | Construction | 2010 |
| Aune Holding AS | Financial services | 2005 |
| Aureum Invest AS | | 2025 |
| Aurora Montering AS | Construction | 2026 |
| Austsidevegen Holding AS | | 1996 |
| Auto Spa AS | Other services | 2021 |
| Automagisk AS | Information & communication | 2025 |
| Auxilio Venture AS | | 2017 |
| Averin AS | Information & communication | 2022 |
| Aviation Technic Norway AS | Manufacturing | 2024 |
| Avion Eiendom AS | Real estate | 2021 |