| Bergmanns AS | Hospitality | 2018 |
| Bessie AS | Financial services | 2011 |
| Bestefars Isbar AS | Hospitality | 2023 |
| Betteks AS | Professional & scientific | 1989 |
| Betterworks AS | Information & communication | 2026 |
| Bevo Invest AS | Real estate | 1997 |
| Bevø Vann & Avløpslag SA | Water & waste | 2016 |
| Big Brother and the Holding Company AS | | 2022 |
| Bil & Eiendom Invest AS | Wholesale & retail | 2025 |
| Bilagenturet AS | Real estate | 2006 |
| Bilartikler AS | Wholesale & retail | 2018 |
| Bilbutikken Frederikstad AS | Wholesale & retail | 2016 |
| BILHANDEL24 AS | Wholesale & retail | 2023 |
| Bilistic AS | Wholesale & retail | 2021 |
| Bilora Bilpleie AS | Other services | 2026 |
| Bilpleie Center AS | Other services | 2015 |
| Bilsalg Norge AS | Wholesale & retail | 2023 |
| Bilverksted Råbekken AS | Information & communication | 2020 |
| Bingo Aarumgården AS | Arts & recreation | 2009 |
| Bit Engineering AS | Professional & scientific | 1995 |
| Bizraise AS | Professional & scientific | 1981 |
| Bjarne Fredriksen AS Tannteknisk Laboratorium | Manufacturing | 1988 |
| Bjsh Holding AS | | 2012 |
| Bjølstad Klinikken AS | Health & social care | 1994 |
| Bjørk Innovation AS | Professional & scientific | 2022 |
| Bjørke-Hill Invest AS | | 2021 |
| Bjørn Andre Moen AS | Wholesale & retail | 2004 |
| Bjørn Andre Moen Drift AS | Wholesale & retail | 2017 |
| Bjørn Gustavsen Eiendom AS | Real estate | 2011 |
| Bjørn Høili Holding AS | Information & communication | 2024 |
| Bjørnar & Morten Reklame Ans | | 1994 |
| Bjørnar Aas AS | Wholesale & retail | 2005 |
| Bjørndalen Eiendom AS | Real estate | 2015 |
| Bjørndalssvingen Eiendom AS | Real estate | 2016 |
| Bjørnen Frisør & Barbershop AS | Other services | 2012 |
| Bjørnstad Utvikling AS | Information & communication | 2011 |
| Bjørnulf Eiendom AS | Real estate | 2005 |
| Blackhawk AS | Real estate | 2021 |
| Blackhawkholding AS | Real estate | 2022 |
| Blastmaster AS | Construction | 2018 |
| Blekkverket AS | Other services | 2016 |
| Bli Synlig AS | Information & communication | 2014 |
| Blikkco AS | Construction | 2018 |
| Bliss Era Studio AS | Other services | 2018 |
| Blisto AS | Real estate | 2001 |
| Blue Haven AS | Real estate | 2025 |
| Blue Haven Eiendom AS | Real estate | 2025 |
| Blue Sea Group AS | Professional & scientific | 2019 |
| BM Byggmester AS | Construction | 2022 |
| BM Forvaltning AS | | 2023 |
| BMD Prosjekt AS | Wholesale & retail | 2023 |
| Bobu Holding AS | Financial services | 2018 |
| Bodahl-Johansen AS | Wholesale & retail | 1992 |
| Bojo Eiendom AS | Real estate | 1976 |
| Boligbygg Utvikling AS | Real estate | 2023 |
| Boligsameiet Gamle Kirkevei 70 BCD | Households | 2012 |
| Boligspar Øst AS | Real estate | 2020 |
| Booking by Hola AS | Arts & recreation | 2026 |
| Boom AS | Information & communication | 2022 |
| Boomboom Invest AS | Financial services | 2008 |
| Boomerang AS | Wholesale & retail | 1993 |
| Borg Utleieservice AS | Administrative & support | 2015 |
| Borg Ventilasjon AS | Manufacturing | 1978 |
| Bosco Holding AS | Financial services | 2013 |
| Boulevard AS | Hospitality | 2026 |
| Boxly AS | Construction | 2010 |
| BP Safety Da | Education | 2009 |
| Brandstorp Holding AS | Real estate | 2007 |
| Brannverntjenesten AS | Administrative & support | 2015 |
| Brattskott 2 AS | Real estate | 2008 |
| Brattskott AS | Real estate | 2006 |
| Brattvang Bygg AS | Construction | 2024 |
| Brennes Auto Fredrikstad AS | Wholesale & retail | 2015 |
| Brestrup Eiendom AS | Real estate | 2005 |
| Bretts Consulting & Production Services AS | Professional & scientific | 2023 |
| Brick & Crunch AS | Hospitality | 2026 |
| Bridgestone Norge | Wholesale & retail | 2015 |
| Brien Holding AS | | 2026 |
| Bright Consulting AS | Professional & scientific | 2025 |
| Bright Performance AS | Professional & scientific | 1987 |
| Brogaten Fysioterapi AS | Health & social care | 1979 |
| Bruktbil Partner AS | Wholesale & retail | 2017 |
| Brygga Eiendom AS | Real estate | 2002 |
| Bryggeriveien 8 AS | Real estate | 2005 |
| Brynild AS | Manufacturing | 2006 |
| Brynild Norge AS | Manufacturing | 2007 |
| Brødrene Helgesen Eiendom AS | Real estate | 2019 |
| Brønnerødlia Eiendom AS | Real estate | 2018 |
| BSB Bolig AS | Real estate | 2017 |
| BSR AS | Wholesale & retail | 2011 |
| Budsjettbil AS | Wholesale & retail | 2025 |
| Bukken Holding AS | Real estate | 2015 |
| Bulktrade AS | Wholesale & retail | 1975 |
| Bure AS | | 2025 |
| Bureaugeist AS | Professional & scientific | 2016 |
| Bureskjær Eiendom AS | Real estate | 2008 |
| Burnback Holding AS | | 2018 |
| Butikk- Og Forretningsutvikling AS | Professional & scientific | 2019 |
| Butikkdrift Martinsen AS | Wholesale & retail | 2026 |
| BVD Bygg AS | Construction | 2026 |