| Arne Matheussen Invest AS | Real estate | 1998 |
| Aro Consult AS | | 2025 |
| Arrangørfelleskapet Medkila Skilag Og If Kilkameratene AS | Arts & recreation | 2025 |
| Art Gymsal Holding AS | | 2025 |
| Articularis Invest AS | Health & social care | 2007 |
| AS Fribo | Real estate | 1972 |
| AS Hans Egedesgt 20 | Households | 1952 |
| AS Hvedings Gate 4 | Real estate | 1949 |
| AS Kaarbøgården | Real estate | 1954 |
| AS Kevitor | Real estate | 1985 |
| AS Lovest.No | Professional & scientific | 2005 |
| AS Norbil Eiendom | Real estate | 1992 |
| AS Tordenskjoldsgate 11 | Real estate | 1989 |
| Asbjørn Selsbanesgate 2 AS | Real estate | 2010 |
| Asiatisk Matsenter AS | Wholesale & retail | 2016 |
| Asiatisk Nettbutikk AS | Hospitality | 2020 |
| Askeladden Bruktbutikk AS | Wholesale & retail | 1993 |
| Aspaker Rør AS | Construction | 2014 |
| Aspen Holding AS | Professional & scientific | 2019 |
| Aspen Ventures AS | | 2026 |
| Aurora Klima AS | Construction | 2022 |
| Auto Nord Ans | Other services | 1992 |
| Auto Nord AS | Other services | 1993 |
| Auto Nord Rental AS | Administrative & support | 2020 |
| Ava Nor AS | Hospitality | 2016 |
| Ava Nor Eiendom AS | Real estate | 2023 |
| Avery Nexus AS | Information & communication | 2025 |
| Awt Opplæring AS | Education | 2017 |
| Ayman AS | Transport & logistics | 2020 |
| Azymeta AS | | 2026 |
| B & B Touring AS | Transport & logistics | 2006 |
| B&W Anlegg AS | Administrative & support | 2023 |
| B&W Dominium AS | Real estate | 2025 |
| B.T.M. Invest AS | Real estate | 2016 |
| Backstrøm Iversen Eiendom AS | Real estate | 1998 |
| Badaniels AS | Wholesale & retail | 2009 |
| Bakerinnen AS | Manufacturing | 2014 |
| Bakerinnen Vol. 1 AS | Manufacturing | 2023 |
| Bakerinnen Vol. 2 AS | Manufacturing | 2019 |
| Bakerringen Nord AS | Administrative & support | 1996 |
| Bakgården Harstad AS | Arts & recreation | 2018 |
| Bakkegaten 1 AS | Real estate | 2016 |
| Balanse Quantum Energisenter AS | Health & social care | 2024 |
| Balorentzen Holding AS | | 2025 |
| Balswick AS | Construction | 2008 |
| Balswick Holding AS | Real estate | 2022 |
| Baltzer AS | Real estate | 2018 |
| Baltzer Invest AS | | 2018 |
| Bareknips AS | Wholesale & retail | 2022 |
| Barents AS | Transport & logistics | 2012 |
| Barents Maritime AS | Transport & logistics | 2014 |
| Barents Ocean AS | Administrative & support | 2016 |
| Bark Spiseri Og Bar AS | Hospitality | 2013 |
| Be Consult AS | Education | 2014 |
| Beautb AS | Other services | 2022 |
| Becwic Hygiene AS | Wholesale & retail | 2011 |
| Befree Studios AS | Arts & recreation | 2025 |
| Bei Jing Restaurant AS | Hospitality | 2026 |
| Bemanning Nord-Norge Avd Hålogaland AS | Administrative & support | 2024 |
| Bendiktsen Maskin Og Transport AS | Construction | 2012 |
| Berad C AS | Information & communication | 2020 |
| Berg & Fagerli Ans | Construction | 1997 |
| Berg Eiendom Harstad AS | Transport & logistics | 2023 |
| Berg Terminaldrift AS | Wholesale & retail | 2025 |
| Berg Transport AS | Transport & logistics | 1998 |
| Berg-Hansen Nord-Norge AS | Administrative & support | 2011 |
| Bergersen Holding AS | | 2019 |
| Bergh Trading AS | Professional & scientific | 2007 |
| Berglundveien 1-3 AS | Real estate | 2020 |
| Bergsengveien 27 AS | Real estate | 2019 |
| Bergsengveien Familiebarnehage AS | Education | 2013 |
| Bergsvåg AS | Agriculture & fishing | 2020 |
| Bergsvågen Næringspark AS | Real estate | 2017 |
| Bergvoll Holding AS | | 2025 |
| Bergvoll Og Walberg Holding AS | | 2025 |
| Bergvoll on & Offshore AS | Professional & scientific | 2023 |
| Bertheus J Nilsen AS | Real estate | 1919 |
| Bertheusgården AS | Real estate | 2011 |
| Besikt AS | Professional & scientific | 2004 |
| Betelgeuse AS | | 2017 |
| BH Harstad AS | Hospitality | 2013 |
| Bilben Holding AS | Real estate | 2009 |
| Bilhuset Harstad AS | Wholesale & retail | 2000 |
| BILPLEI1 Harstad AS | Other services | 1999 |
| Biltrend Eiendom Harstad AS | Real estate | 2003 |
| Biltrend Harstad AS | Wholesale & retail | 2005 |
| Biltrend Stangnes AS | Real estate | 2022 |
| Bilutstyr Nor AS | Wholesale & retail | 2016 |
| Binv AS | | 2023 |
| Bivuakk AS | Wholesale & retail | 2021 |
| Bjarkøy AS | Real estate | 2018 |
| Bjørk-Holding AS | Real estate | 2015 |
| Bjørn Brøndbo Holding AS | | 1997 |
| Bjørnar Pedersen's Eiendoms-Takst AS | Real estate | 2025 |
| Bjørnebåsen Barnehage SA | Education | 1992 |
| Black & White Trades AS | Professional & scientific | 2026 |
| Blikkenslager T.M.Killi AS | Construction | 2024 |
| Blissful Twins Media AS | Professional & scientific | 2026 |
| Blokken Grunneierlag SA | Real estate | 1971 |
| Blomsø Bakeri & Konditori AS | Manufacturing | 1994 |