| Brørby Eiendomsmegling AS | Real estate | 2016 |
| BSG - Maskin AS | Administrative & support | 2018 |
| Btbil AS | Wholesale & retail | 2023 |
| BTK Holding AS | Construction | 2007 |
| Buind Eiendom AS | Real estate | 2006 |
| Buind Holding AS | Manufacturing | 1994 |
| Bukollen AS | Real estate | 2018 |
| Burger Buddies AS | Hospitality | 2024 |
| Busandvegen SA | Real estate | 1968 |
| Busebakk AS | Real estate | 2005 |
| Buskerud Bad & Rørservice AS | Construction | 2022 |
| Buskerud Bil AS | Wholesale & retail | 2024 |
| Buskerud Bygg Og Anlegg AS | Real estate | 2017 |
| Buskerud Fasadevask AS | Administrative & support | 2025 |
| Buskerud Golf AS | Arts & recreation | 2024 |
| Buskerud Holding AS | Wholesale & retail | 2024 |
| Buskerud Snekkerservice AS | Construction | 2018 |
| Buskerud Snekkerservice Holding AS | Real estate | 2012 |
| Buskerud Snekkerservice Utvikling AS | Real estate | 2018 |
| Buskerud Solfilm Ans | Wholesale & retail | 1991 |
| Buskerud Solskjerming AS | Construction | 2025 |
| Buskerud Transportsentral AS | Transport & logistics | 2015 |
| Buttentjern Jaktskytesenter SA | Arts & recreation | 2006 |
| Byberg Øst Holdingselskap AS | | 2021 |
| Byens Tannlege AS | Health & social care | 2025 |
| Bygdinvegen 59 AS | Real estate | 2021 |
| Bygg & Sveise Service AS | Construction | 2014 |
| Bygg Kesmin AS | Construction | 2022 |
| Bygg Og Anlegg Tekniske Consulent AS | Professional & scientific | 1997 |
| Bygg Solution & Service AS | Construction | 2015 |
| Bygg Style Holding AS | Construction | 2022 |
| Bygg- Og Tømrermester Nicolaj Vogter AS | Construction | 2016 |
| Bygghjelpen AS | Professional & scientific | 2019 |
| Byggmester Berger AS | Construction | 2013 |
| Byggmester Philip Meijers AS | Construction | 2011 |
| Byggmester Sundberg AS | Construction | 2016 |
| Byggmester Trond Myhre AS | Construction | 1998 |
| Byggmester Vikre AS | Construction | 2022 |
| Byggmesteren Hønefoss AS | Construction | 2002 |
| Byggrådgivning Hønefoss AS | | 2022 |
| Byggsolutions AS | Professional & scientific | 2024 |
| Bymatko AS | Wholesale & retail | 2020 |
| Byporten Hønefoss AS | Real estate | 1998 |
| Bård AS | Wholesale & retail | 2013 |
| Bærum Hageservice AS | Administrative & support | 2014 |
| Bøler Butikkeiendom AS | Real estate | 2016 |
| C.A.I. Holding AS | Real estate | 2014 |
| C2 Holding AS | | 2026 |
| Cablemec AS | Manufacturing | 2024 |
| Caldera AS | Professional & scientific | 2005 |
| Capelli Hårstudio AS | Other services | 2021 |
| Capitaniofsweden AS | Wholesale & retail | 2022 |
| CARAVAN1 Hønefoss AS | Wholesale & retail | 2022 |
| Care of Ringerike AS | Health & social care | 2024 |
| Carghi AS | Wholesale & retail | 2012 |
| Carghi Holding AS | | 2025 |
| Carmen Hårstudio AS | Other services | 2007 |
| Catch Hundetrening AS | Agriculture & fishing | 2015 |
| Catch Media AS | Professional & scientific | 2005 |
| Cavatoppen Holding AS | Real estate | 2000 |
| Cba 100 AS | Hospitality | 2009 |
| Cellulosevegen 2 AS | Real estate | 2007 |
| Cenergi AS | Wholesale & retail | 1993 |
| Certificat AS | Administrative & support | 2016 |
| Ceska Invest AS | | 2022 |
| Chicken Corner AS | Hospitality | 2018 |
| Christian a. Berg AS | Real estate | 2005 |
| Christiansen Bygg AS | Construction | 2011 |
| Chrono Urmaker & Foto AS | Wholesale & retail | 1989 |
| City Eiendom 1 AS | Real estate | 2006 |
| City-Gården AS | Real estate | 1986 |
| CKW Holding | | 2022 |
| CLH Eiendom AS | | 2023 |
| Clint AS | Hospitality | 2024 |
| CM Engros AS | Wholesale & retail | 2023 |
| Cma AS | | 2018 |
| Colic Button AS | Professional & scientific | 2021 |
| Colour Energy World AS | Professional & scientific | 1985 |
| Compute-It AS | Information & communication | 2017 |
| Containerservice Ringerike AS | Administrative & support | 2010 |
| Cosmeticnursejulie AS | Health & social care | 2022 |
| Cosmic Noise AS | Information & communication | 2012 |
| Costa AS | Wholesale & retail | 1992 |
| Costa Boes AS | Real estate | 2017 |
| Cosy Life AS | Education | 2020 |
| Couture AS | Wholesale & retail | 2022 |
| Currus AS | Wholesale & retail | 2020 |
| D-Agency AS | Wholesale & retail | 2020 |
| D-R Auto Invest AS | Wholesale & retail | 2023 |
| D. Hansen Holding AS | | 2024 |
| Dagligvare Askim Eiendom Ans | Real estate | 2002 |
| Dagligvare Hønefoss Eiendom Ans | Real estate | 2003 |
| Daisy AS | Wholesale & retail | 2012 |
| Dalensthi AS | Professional & scientific | 2024 |
| Dalsbråten Barnehage SA | Education | 1989 |
| Datacity AS | Information & communication | 1997 |
| Datasvar AS | Wholesale & retail | 2000 |
| Datasvar Holding AS | Financial services | 2018 |
| De Eiendom AS | Real estate | 2024 |
| De Vries Da | Transport & logistics | 2017 |