| Avløpsvakten AS | Construction | 2007 |
| AW34A AS | Real estate | 2019 |
| Aznex AS | Information & communication | 2026 |
| B & G Invest AS | Real estate | 2017 |
| B & S Invest AS | Professional & scientific | 2010 |
| B Og L Holding AS | Real estate | 2005 |
| B-O-T-Holding AS | | 2023 |
| Baker Østby AS | Wholesale & retail | 2014 |
| Balisbalis AS | | 2019 |
| Baltic Partners AS | Financial services | 1996 |
| Bamm Invest AS | | 2019 |
| Banco AS | Real estate | 1989 |
| Banco Management AS | Real estate | 1990 |
| Baraad AS | Professional & scientific | 2024 |
| Barretten AS | Wholesale & retail | 2022 |
| Barrica AS | Information & communication | 2020 |
| Barwa System AS | Professional & scientific | 2023 |
| Bass AS | Information & communication | 1967 |
| Bausa AS | Arts & recreation | 2024 |
| Bauta Omsorg AS | Health & social care | 2024 |
| Beauty Kraft AS | Health & social care | 2023 |
| Belgravia Holding AS | Financial services | 1973 |
| Bergerveien 5 AS | Real estate | 2017 |
| Best Practice Institute AS | Real estate | 1998 |
| Bethel Håndverker AS | Construction | 2025 |
| Betonmast Asker Og Bærum AS | Construction | 2000 |
| Better Performance AS | Health & social care | 2013 |
| Bexp AS | Administrative & support | 1999 |
| BHL Accounting AS | Professional & scientific | 2016 |
| BHL AS | Professional & scientific | 2025 |
| Bigbuy AS | Wholesale & retail | 2020 |
| Bilservice Sandvika AS | Other services | 2016 |
| Biomedic AS | Wholesale & retail | 2021 |
| Biomedicallab AS | Health & social care | 2025 |
| Biral AS | Real estate | 1990 |
| Biral Lubricants Norway AS | Manufacturing | 1971 |
| Birkheim Frukt Og Tobakk | Wholesale & retail | 1970 |
| Bjerkely Interiør AS | Professional & scientific | 2021 |
| Bjerkås Restauranthuset AS | Wholesale & retail | 2012 |
| Bjorbu Holdings AS | Professional & scientific | 2007 |
| Bjønnebu Holding AS | | 2026 |
| Bjørkildsen Holding AS | Real estate | 2016 |
| Bjørklund Sandvika AS | Wholesale & retail | 2009 |
| Bjørnsvikveien 28 AS | Real estate | 2013 |
| Bke Eie AS | Real estate | 2005 |
| Blow Eiendom AS | Real estate | 2016 |
| Blue Bay AS | Professional & scientific | 2015 |
| Blue Nau AS | Professional & scientific | 2022 |
| Bluenote AS | | 2025 |
| Blå Fugl AS | Wholesale & retail | 2002 |
| Bogsrud AS | | 2025 |
| Bogstadveien 46 B AS | Real estate | 2007 |
| Bokvalitet Arkitekter AS | Professional & scientific | 2018 |
| Bokvalitet Hus & Hytter AS | Real estate | 2018 |
| Bokvalitet Prosjekt AS | Real estate | 2024 |
| Bold Advice & Investment AS | Professional & scientific | 2023 |
| Borgen Antennelag SA | Information & communication | 1991 |
| Braathens IT AS | Information & communication | 2002 |
| Brainware Industrier AS | Real estate | 2009 |
| Brandmobil AS | Wholesale & retail | 2025 |
| Brataas Invest AS | Financial services | 2017 |
| Brif AS | Real estate | 2005 |
| Brimer Horizon AS | Wholesale & retail | 2006 |
| Bruenech AS | Wholesale & retail | 2002 |
| Bruusgaard International AS | Wholesale & retail | 2020 |
| BTB Bærum Transportbyrå AS | | 1987 |
| Bubble Gum AS | | 2021 |
| Bufab Norge AS | Wholesale & retail | 1996 |
| Bui Nails AS | Other services | 2019 |
| Burgas Enwia AS | Hospitality | 2014 |
| Busycom AS | | 1985 |
| Buviktind AS | Professional & scientific | 2021 |
| Bygdøynes Horisont AS | Real estate | 2019 |
| Byrom Utleiemegling AS | Real estate | 2025 |
| Byutvikling AS | Real estate | 1992 |
| Bærum Bil & MC Skole AS | Education | 2026 |
| Bærum Bilpleie AS | Other services | 2023 |
| Bærum Bilsenter AS | Wholesale & retail | 2025 |
| Bærum Blomsterdesign AS | Wholesale & retail | 1987 |
| Bærum Eiendomsmegler Selskap AS | Real estate | 2016 |
| Bærum Eiendomstaksering AS | Real estate | 2012 |
| Bærum Gulv AS | Construction | 2011 |
| Bærum Lungeklinikk AS | Health & social care | 2024 |
| Bærum Muskel Og Leddklinikk AS | Health & social care | 2015 |
| Bærum Optikk AS | Wholesale & retail | 1984 |
| Bærum Tungbilskole AS | Education | 2025 |
| Bærum Øyeklinikk AS | Health & social care | 2007 |
| Bærum-Sandvika Tannlegevakt AS | Health & social care | 2014 |
| Bærums Verk Tømrermesterfirma AS | Construction | 2020 |
| Bærumsklinikken AS | Health & social care | 2009 |
| Cadex Infotech AS | Professional & scientific | 2009 |
| Cambiare AS | Professional & scientific | 2021 |
| Cami AS | | 2026 |
| Camilla Cafe Ans | Hospitality | 2000 |
| Cappelens Gate 15 AS | Real estate | 2012 |
| Caraway A/S | Manufacturing | 2019 |
| Carbo Culture AS | Professional & scientific | 2024 |
| Carlsson Consult AS | Professional & scientific | 1986 |
| Carrus AS | Construction | 2023 |
| Catchlight Fotostudio AS | Professional & scientific | 2002 |