| Armita Invest AS | Wholesale & retail | 2011 |
| Armonia AS | Professional & scientific | 2021 |
| Armor AS | Financial services | 2018 |
| Armstrong Sci AS | Real estate | 2006 |
| Army Shop AS | Wholesale & retail | 1995 |
| Arnar AS | Manufacturing | 2005 |
| Arnar Bjorøy AS | Arts & recreation | 2026 |
| Arne B Corneliussen AS | Wholesale & retail | 1987 |
| Arne Berg Consult AS | Professional & scientific | 2010 |
| Arne Blystad AS | Transport & logistics | 1993 |
| Arne Eidshagen AS | | 2024 |
| Arne Garborgs Plass 4 AS | Arts & recreation | 2019 |
| Arne Gulbrandsen AS | Other services | 1967 |
| Arne Haugli AS | Health & social care | 2013 |
| Arne Holsen Holding AS | | 2023 |
| Arne Ingier Bil AS | Wholesale & retail | 1991 |
| Arne J Eidal AS | Wholesale & retail | 1996 |
| Arne Karlsen Maler- Og Tapetservice AS | Construction | 2015 |
| Arne Martin Hoel AS | Real estate | 2011 |
| Arne Mjøs Invest AS | Real estate | 1997 |
| Arne Munz Holding AS | | 2025 |
| Arne Stang Invest AS | Mining & quarrying | 2014 |
| Arne Syversen Eiendom AS | Real estate | 1962 |
| Arnearch AS | | 2022 |
| Arneberg Consulting AS | Professional & scientific | 2006 |
| Arnebråtveien 137 AS | Real estate | 2022 |
| Arnebråtveien 20 AS | Real estate | 2026 |
| Arnebråtveien 22 AS | Real estate | 2019 |
| Arnebråtveien 23 AS | Real estate | 2022 |
| Arnebråtveien AS | Real estate | 2006 |
| Arnedal Invest AS | Wholesale & retail | 2019 |
| Arnegårdsveien 1 AS | Real estate | 2021 |
| Arneirica AS | | 2021 |
| Arnema Invest AS | | 2017 |
| Arnemannsveien 7 AS | Real estate | 1940 |
| Arnes Bilvask AS | Other services | 2012 |
| Arnesen Christensen & Co AS | Professional & scientific | 1933 |
| Arnesen Entertainment AS | Information & communication | 2023 |
| Arnestad Storkjøkken AS | Wholesale & retail | 1991 |
| Arnestadveien 1 AS | Real estate | 2008 |
| Arnestein Ans | Real estate | 2011 |
| Arnfinn Lindseth AS | | 2016 |
| Arngren Sky Commuter AS | Wholesale & retail | 1992 |
| Arnhest AS | Professional & scientific | 2026 |
| Arnjoh Holding AS | Real estate | 2015 |
| Arnkom AS | Professional & scientific | 2018 |
| Arnkværn Miljø Og Renovasjon Oslo AS | Water & waste | 2013 |
| Arnoldo AS | Real estate | 2011 |
| Arnor AS | Real estate | 2006 |
| Arnrock AS | | 2024 |
| Arnstad Holding AS | Financial services | 2018 |
| Arnstad Management AS | Professional & scientific | 2015 |
| Arnstein Arnebergs Vei 30 Næring AS | Real estate | 2025 |
| Arnt Myrvoll AS | Administrative & support | 1998 |
| Arntco AS | Information & communication | 1986 |
| Arntsen Remøy Invest Da | Real estate | 2010 |
| Arnulf Strøm Eiendom AS | Real estate | 1964 |
| Aro Asset Invest AS | | 2025 |
| Aro Holding AS | | 2022 |
| Aro Invest AS | | 2025 |
| Aro Investment AS | Real estate | 2006 |
| Aro Profilering AS | Manufacturing | 2020 |
| Arod Holding AS | Real estate | 2017 |
| Arom Invest AS | Financial services | 2007 |
| Aron Capital AS | Financial services | 2007 |
| Aron Da | Information & communication | 1997 |
| Arona Trehus AS | Wholesale & retail | 2015 |
| Arons Vei 5 Eiendom AS | Real estate | 2022 |
| Aros Holding AS | Information & communication | 2022 |
| Aros IT Consulting AS | Information & communication | 2022 |
| Around AS | Information & communication | 2025 |
| Arowya AS | Energy | 2016 |
| Arox Tunnel AS | Construction | 2020 |
| Arpol AS | Construction | 2017 |
| Arpu Holding AS | Financial services | 2017 |
| Arqon Group AS | | 2026 |
| Arr AS | Real estate | 2006 |
| Arrangementsikring Da | Administrative & support | 1998 |
| Arrat AS | Manufacturing | 2005 |
| Arret AS | Financial services | 2010 |
| Arribatec Group ASA | Professional & scientific | 1998 |
| Arribatec Norge AS | Information & communication | 2017 |
| Arrivals AS | Professional & scientific | 2019 |
| Arrive AS | | 2017 |
| Arrl Invest AS | Financial services | 2016 |
| Arrow Chemicals | Administrative & support | 1995 |
| Arrow Ecs Norway AS | Wholesale & retail | 1998 |
| Arrowforge AS | Information & communication | 2012 |
| Ars Group AS | Transport & logistics | 2021 |
| Ars Support AS | Information & communication | 2025 |
| Arsgentarii AS | Wholesale & retail | 1996 |
| Arshad Advokater AS | Professional & scientific | 2026 |
| Arslan Holding AS | Professional & scientific | 2018 |
| Arstone AS | Real estate | 2006 |
| Art & Hus AS | Construction | 2024 |
| Art & Mat AS | Hospitality | 1996 |
| Art & Soul Tattoo AS | Other services | 2018 |
| Art Attack AS | Wholesale & retail | 2021 |
| Art Beauty Center AS | Other services | 1989 |
| Art Boligstyling AS | Professional & scientific | 2019 |