| A Hamstad AS | Wholesale & retail | 1987 |
| A Tvete AS | Health & social care | 2018 |
| Aasen Alarm AS | Construction | 2014 |
| AB Maskin Bernt Lande Og Arnstein Aune Ans | Construction | 1993 |
| Abc Stormarked AS | Wholesale & retail | 1982 |
| Abel Meyers Gate 30 AS | Real estate | 2019 |
| Abel Meyers Gate 8 AS | Real estate | 2022 |
| Abel Meyersgate 2 AS | Real estate | 2007 |
| Abel Meyersgate 3 AS | Real estate | 2007 |
| Abel Meyersgate AS | Real estate | 2017 |
| Abel Namsos AS | Other services | 2002 |
| Abygger AS | Construction | 2024 |
| Advokat Ivar Hustad AS | Real estate | 2005 |
| Advokatfirmaet Lysø AS | Professional & scientific | 1997 |
| Aelektriker AS | Construction | 2019 |
| Agnema Invest AS | | 2023 |
| Akvacrew AS | Agriculture & fishing | 2025 |
| Akvacrew Holding AS | | 2025 |
| Alcaden AS | Real estate | 2005 |
| Alcaden Eiendom AS | | 2026 |
| Alekan AS | Wholesale & retail | 2023 |
| Alex Investment AS | Wholesale & retail | 2007 |
| Amor AS | Real estate | 2016 |
| Anella AS | Financial services | 2016 |
| Anm Invest AS | Professional & scientific | 2017 |
| Anna J AS | Wholesale & retail | 2006 |
| Apportunity AS | Information & communication | 2025 |
| Aqua Staff AS | Administrative & support | 2024 |
| Aquapartners AS | Administrative & support | 2024 |
| Arcon Group AS | Wholesale & retail | 2026 |
| Arcon Prosjekt AS | Professional & scientific | 1991 |
| Arcreare AS | Professional & scientific | 1998 |
| Areal Invest AS | Real estate | 2015 |
| Argona Invest AS | Professional & scientific | 2012 |
| Arholmen AS | Real estate | 2012 |
| Arka Eiendommer AS | Real estate | 2018 |
| Arkaia AS | Professional & scientific | 2025 |
| Arkplan AS | Professional & scientific | 1999 |
| AS Hans Ofstad Efterfølger | Wholesale & retail | 1968 |
| AS John Nesser | Agriculture & fishing | 2015 |
| AS Per Aursand | Real estate | 1967 |
| AS Sunnanbruket | Real estate | 1916 |
| Asbjørn Olsen Og Sønner AS | Real estate | 1975 |
| Atle Brobakken Invest AS | Real estate | 2005 |
| Atoma Nordic AS | Information & communication | 2026 |
| Aupefi AS | Financial services | 2015 |
| Autoforum Eiendom AS | Real estate | 1996 |
| Autokontroll Kenneth Rognerud AS | Professional & scientific | 2015 |
| B Røthe AS | Wholesale & retail | 1975 |
| B Tre AS | Real estate | 2007 |
| Bankgården Grong AS | Real estate | 2020 |
| Barstad Trelast AS | Wholesale & retail | 2011 |
| Bartlet Holding AS | Financial services | 2008 |
| Bawa Handel AS | Wholesale & retail | 2008 |
| BBX Ledang AS | Real estate | 2021 |
| Beauty of Fame AS | Wholesale & retail | 2013 |
| Beem AS | Professional & scientific | 1986 |
| Beem Eiendom AS | Real estate | 2025 |
| Bege Eiendom AS | Real estate | 2003 |
| Bendix Konsulting AS | Wholesale & retail | 2023 |
| Beta Eiendom AS | Real estate | 2002 |
| Beta Invest AS | Financial services | 1998 |
| Betu AS | Wholesale & retail | 1988 |
| Bilsenteret Eiendom Hestmarka AS | Real estate | 2006 |
| Bilsenteret Eiendom Spillum AS | Real estate | 2006 |
| Birger Pedersen AS | Construction | 1988 |
| Bjørgan Eiendom AS | Real estate | 2021 |
| Bjørgan Fritid AS | Real estate | 2011 |
| Bjørn Hågensen AS | Professional & scientific | 1970 |
| Bjørnar Nilsen AS | Wholesale & retail | 2018 |
| Bjørum Barnehage AS | Education | 2015 |
| Bjørum Holding AS | Real estate | 2014 |
| Bjørum Invest AS | | 2016 |
| Blekk Magic AS | Other services | 2023 |
| Blom Arkitekter AS | Professional & scientific | 2021 |
| Blomsterhjørnet Olsvik AS | Wholesale & retail | 2017 |
| Bobil Og Caravan Lager AS | Real estate | 2025 |
| Bobil Spillum AS | Wholesale & retail | 2018 |
| Bobyn Kjøpesenter AS | Real estate | 2020 |
| Bolkan Invest AS | Administrative & support | 2005 |
| Borkmo AS | Wholesale & retail | 2024 |
| Borkmo Holding AS | Wholesale & retail | 2005 |
| Bpas Invest AS | Construction | 2018 |
| Braa AS | Hospitality | 2022 |
| Braa Bar Og Barmat AS | Hospitality | 2022 |
| Brakka AS | Real estate | 2024 |
| Brandtzæg AS | | 2026 |
| Breidablikkvegen 4 AS | Real estate | 2017 |
| Breivika Consulting AS | Professional & scientific | 2023 |
| Brikseli Gård Og Opplevelser Ans | Hospitality | 2017 |
| Brillehuset Gifstad Og Ledang AS | Wholesale & retail | 2001 |
| Brillehuset Namsos AS | Wholesale & retail | 1998 |
| Brimm Holding AS | | 2022 |
| Brinc AS | Financial services | 2016 |
| Brobakken Holding AS | Hospitality | 2020 |
| Brygga Dental Eiendom AS | Real estate | 2018 |
| Brygga Regnskap AS | Professional & scientific | 2000 |
| Bryggekompaniet AS | Hospitality | 2002 |
| Bråholmen Boligutleie AS | Real estate | 2013 |
| Bråholmen Eiendom AS | Real estate | 2006 |