| Bark Bazar AS | Professional & scientific | 2012 |
| Barofe AS | Information & communication | 2018 |
| Be Visible AS | Arts & recreation | 2017 |
| Bear Capital AS | | 2022 |
| Beba Eiendom AS | Real estate | 2001 |
| Bedriftskraft AS | Education | 2012 |
| Bedynamic AS | Professional & scientific | 2017 |
| BEE612 AS | Information & communication | 2016 |
| Bego AS | Construction | 2010 |
| Bei AS | | 2018 |
| Bekkesstua Bygg AS | Construction | 2026 |
| Bekkestua 1 Wok & Sushi AS | Hospitality | 2025 |
| Bekkestua Advokatkontor AS | Professional & scientific | 2020 |
| Bekkestua Beautycenter Ma Belle AS | Other services | 2017 |
| Bekkestua Fastlegekontor Da | Health & social care | 2010 |
| Bekkestua Fysioterapi Og Manuellterapi Da | Health & social care | 2004 |
| Bekkestua Hagesenter AS | Wholesale & retail | 2009 |
| Bekkestua Holding AS | | 2024 |
| Bekkestua Kiropraktikk Og Helse AS | Health & social care | 2001 |
| Bekkestua Kjøkkenstudio AS | Wholesale & retail | 2013 |
| Bekkestua Optikk AS | Wholesale & retail | 2008 |
| Bekkestua Pizza AS | Hospitality | 1994 |
| Bekkestua Skredderi & Renseri AS | Other services | 2012 |
| Bekkestua Specsavers AS | Wholesale & retail | 2020 |
| Bekkestua Tannlegesenter AS | Health & social care | 2018 |
| Bekkestua Tannmedisin AS | Health & social care | 2016 |
| Bekkestua Torg Ans | Real estate | 2002 |
| Bekkestua Trafikkskole AS | Education | 2022 |
| Bekkestua Wok & Sushi AS | Wholesale & retail | 2021 |
| Bekkestualegene Da | Health & social care | 2010 |
| Bekkestuapsykologen AS | Health & social care | 2022 |
| Benzen AS | Professional & scientific | 2007 |
| Bergwitz Holding AS | | 2026 |
| Bernhoft Holding AS | | 2018 |
| Bertelsen Invest AS | | 2024 |
| Besse&Bessa Invest AS | | 2026 |
| Big Enough Global AS | Education | 2020 |
| Bijou AS | | 2020 |
| Bio Plastic AS | Professional & scientific | 2018 |
| Birch Holding AS | | 2022 |
| Birhai Holding AS | Wholesale & retail | 2021 |
| Birkelundsveien 73 AS | Real estate | 1946 |
| Bittelille AS | Professional & scientific | 2017 |
| Bjerkelund Eiendom AS | Real estate | 2001 |
| Bjerkåsholmen Marina AS | Wholesale & retail | 2003 |
| Bjoast AS | Information & communication | 2024 |
| Bjugstad-Hårsaker AS | | 2023 |
| Bjørn Hallmo AS | Real estate | 2005 |
| BKM Consultant AS | Professional & scientific | 2004 |
| Blaa Pubdrift AS | Hospitality | 2013 |
| Blaafjell Holding AS | | 2024 |
| Blakset Consulting AS | Professional & scientific | 2021 |
| Blakstad Hageby Garasjelag AS | Real estate | 1965 |
| Blue Chip Invest AS | Financial services | 2018 |
| Blue Dream AS | Professional & scientific | 2007 |
| Blue Horseshoe AS | Transport & logistics | 2021 |
| Blue Tulip AS | Real estate | 2001 |
| Blue Wave Therapeutics AS | Professional & scientific | 2021 |
| Bluelat AS | | 2009 |
| Blumenlied Holding AS | | 2025 |
| Blåkampen Holding AS | Real estate | 2021 |
| BMF Invest AS | Real estate | 2020 |
| Bocca Bekkestua AS | Hospitality | 2023 |
| Bocca Mosetertoppen AS | Hospitality | 2021 |
| Bojarv Holding AS | | 2026 |
| Bols Prosjekt AS | Professional & scientific | 1995 |
| Bon AS | Real estate | 2014 |
| Bonatt AS | Administrative & support | 2026 |
| Bonavista AS | Health & social care | 2000 |
| Bony AS | Real estate | 2025 |
| Borg AS | Real estate | 1988 |
| Boss Invest AS | Professional & scientific | 2013 |
| Bowoso AS | Real estate | 2011 |
| Bp-Bygg AS | Construction | 2012 |
| Brainstorm AS | Professional & scientific | 2011 |
| Brath Invest AS | | 2025 |
| Breirem Invest AS | | 2024 |
| Brevik Risk Management AS | Professional & scientific | 2007 |
| Brune & Co AS | Professional & scientific | 2003 |
| Brunmo Invest AS | Real estate | 2022 |
| Bryn Forvaltning AS | Financial services | 2005 |
| Btech Invest AS | Construction | 2000 |
| Bugten Holding AS | Real estate | 2014 |
| Bumath Holding AS | | 2025 |
| Burum AS | Real estate | 1998 |
| Buttonwood AS | Real estate | 2011 |
| Buvang AS | Information & communication | 2023 |
| BVS Bra Holding AS | | 2008 |
| Bygg- Og Energisystemer AS | Manufacturing | 1985 |
| Byggvindu AS | Construction | 2009 |
| Bærum Barnelegeklinikk AS | Health & social care | 2010 |
| Bærum Bygg Og Bad Grupen AS | Construction | 2026 |
| Bærum Maling Og Restaurering AS | Construction | 2021 |
| Bærum Ombruk AS | Wholesale & retail | 2023 |
| Bærum Pizza & Grill Bekkestua AS | Hospitality | 2013 |
| Bærum Rørleggervakt AS | Construction | 2025 |
| Bærum Tannregulering AS | Health & social care | 2012 |
| Bærumsmarka Fus Barnehage AS | Education | 2019 |
| C&M Aesthetics Bekkestua AS | Other services | 2025 |
| C.O.B. Group AS | Real estate | 2010 |