| Blueprint Classics AS | Other services | 2024 |
| Bluesun AS | Information & communication | 2013 |
| Bluesynergi AS | Administrative & support | 2023 |
| Blynk AS | Information & communication | 2024 |
| Blå Kors Eiendom Drammen AS | Real estate | 2005 |
| Blå Magi AS | Arts & recreation | 2020 |
| Blåbærtoppen Barnehage SA | Education | 2001 |
| Blåfjell Utvikling AS | Real estate | 2021 |
| Blåis AS | Information & communication | 2015 |
| Blåveispiken Blomster AS | Wholesale & retail | 2010 |
| BM Energy AS | Energy | 2026 |
| BM Hodling AS | Real estate | 2020 |
| BMS Norge AS | Construction | 2010 |
| Boards and Wine AS | Education | 2023 |
| Boassistanse AS | Real estate | 2013 |
| Bodyfly Helsesenter AS | Health & social care | 2013 |
| Bofamo Eiendom AS | Real estate | 2018 |
| Bois AS | Real estate | 2014 |
| Bokføring Og Service Ans | Professional & scientific | 1995 |
| Bokholdern AS | Professional & scientific | 2025 |
| Bokhylle-Spesialisten AS | Manufacturing | 2013 |
| Boklar AS | Construction | 2026 |
| Bokstav Og Bilde AS | Information & communication | 2005 |
| Bolc AS | Real estate | 2017 |
| Bold Flag AS | Information & communication | 1996 |
| Bolig Forvaltning Og IT AS | Information & communication | 2019 |
| Bolig Holding AS | | 2025 |
| Boligfaktura AS | Professional & scientific | 2020 |
| Boliginkasso AS | Administrative & support | 2017 |
| Boligtekst AS | Professional & scientific | 2011 |
| Bolstad Wam Ans | Real estate | 1988 |
| Bomege AS | Professional & scientific | 2018 |
| Bondens Marked Drammen SA | Wholesale & retail | 2013 |
| Bonzai AS | Manufacturing | 2012 |
| Bonzanigo AS | Arts & recreation | 2010 |
| Boreala AS | | 2023 |
| Boredgames AS | Information & communication | 2024 |
| Borgan Kjøkken Og Bad AS | Wholesale & retail | 2010 |
| Borge Holdings AS | Financial services | 2017 |
| Borge Maskin Entreprenør AS | Construction | 2021 |
| Borge Revisjon AS | Professional & scientific | 2009 |
| Borge Rørservice AS | Construction | 2015 |
| Borgeskogen Eiendom 51 AS | Real estate | 2010 |
| Borthwick Invest AS | | 2019 |
| Bosgen AS | Health & social care | 2022 |
| Botanisk Hjem AS | Wholesale & retail | 2020 |
| Botex Engros AS | Wholesale & retail | 1975 |
| Bovg Bygg Og Våtrom AS | Construction | 2002 |
| Bovg Eiendom AS | Real estate | 2025 |
| Bovg Elektro AS | Construction | 2019 |
| Bovg Group AS | Construction | 2023 |
| Bovg Malertjenester AS | Construction | 2019 |
| Bovg Takst AS | Real estate | 2025 |
| Bowling 1 Drammen AS | Arts & recreation | 2000 |
| Boxon AS | Wholesale & retail | 2008 |
| Bozzar AS | Wholesale & retail | 2003 |
| Bozzar Drift AS | Wholesale & retail | 2017 |
| Bozzar Nett AS | Wholesale & retail | 2025 |
| Bpe Bygg Invest AS | Construction | 2016 |
| Bpi Norway AS | Wholesale & retail | 2022 |
| BR Eiendom AS | Real estate | 2023 |
| BR Vekst AS | Real estate | 2024 |
| Braak Records Da | Information & communication | 2022 |
| Braandahl AS | Information & communication | 2016 |
| Braathen AS | Real estate | 1992 |
| Brabo AS | Real estate | 1995 |
| Bradypus Invest AS | Real estate | 2021 |
| Brage Eiendomservice AS | Administrative & support | 2025 |
| Brage Regnskap AS | Professional & scientific | 2003 |
| Brager Eiendom AS | Real estate | 1986 |
| Brager Invest AS | Professional & scientific | 2024 |
| Bragerhagen 32 AS | Real estate | 1989 |
| Bragernes Atrium AS | Real estate | 2013 |
| Bragernes Atrium Holding AS | Real estate | 2014 |
| Bragernes Eiendomsmegling AS | Real estate | 2024 |
| Bragernes Endospesialist AS | Health & social care | 2011 |
| Bragernes Konsert AS | Professional & scientific | 2005 |
| Bragernes Legesenter AS | Health & social care | 2019 |
| Bragernes Servicesenter AS | Wholesale & retail | 2021 |
| Bragernes Øyeklinikk AS | Health & social care | 2025 |
| Brageteatret - Regionteater for Buskerud AS | Arts & recreation | 2000 |
| Brainmed AS | Wholesale & retail | 2004 |
| Brakar AS | Public administration | 2009 |
| Brakerøya Næringspark AS | Real estate | 2012 |
| Brakohus AS | Real estate | 1995 |
| Bram AS | Professional & scientific | 2001 |
| Branas Hytteutvikling AS | Real estate | 2018 |
| Branas Utvikling AS | Real estate | 2019 |
| Brandsuite AS | Health & social care | 2024 |
| Brandt & Meland Da | Professional & scientific | 1994 |
| Bransjereiser AS | Administrative & support | 2005 |
| Bratrade Engros AS | Wholesale & retail | 2015 |
| BRB Invest AS | Real estate | 2017 |
| Brdr Andersen & Krussand Værktøimaskinfabrik AS | Real estate | 2023 |
| Breathe AS | Education | 2026 |
| Breisass Invest AS | | 2021 |
| Breivollveien AS | Real estate | 2013 |
| Brekmojølsen Da | Real estate | 2022 |
| Bremer Konow Rettshjelp AS | Professional & scientific | 2023 |
| Brencel AS | Professional & scientific | 2022 |