| Buskerud Ventilasjon AS | Professional & scientific | 2015 |
| Bussedalen 7 AS | Real estate | 2014 |
| BWH Hotel Group AS | Administrative & support | 2014 |
| Byggfornyelse AS | Construction | 2007 |
| Byggmester Birkelund AS | Construction | 2012 |
| Byggspiten AS | Construction | 2019 |
| Byob Eiendom AS | Real estate | 2020 |
| Bytesize AS | Information & communication | 2006 |
| Bård Holtan Invest AS | | 2022 |
| Båsen AS | Professional & scientific | 2023 |
| Bøe Johnsen Eiendom AS | Real estate | 2011 |
| Bøhmer Eiendom AS | Real estate | 1986 |
| Bøhmer Finans AS | Financial services | 2008 |
| Bøhmer Haugen Eiendom AS | Real estate | 2004 |
| Bøhmer Holding AS | | 1988 |
| Bøhmer Invest AS | Financial services | 2008 |
| C Optikk AS | Wholesale & retail | 2005 |
| C12 Eiendom AS | Real estate | 2021 |
| Caravan Shop AS | Wholesale & retail | 1985 |
| Caro & Cris AS | Wholesale & retail | 2014 |
| Casa Andres Consulting AS | Real estate | 2023 |
| Caveman. AS | Wholesale & retail | 2019 |
| Cbris Holding AS | | 2026 |
| Central Utleie Da | Real estate | 2007 |
| Centrum Auto AS | Wholesale & retail | 1997 |
| CG Eiendom AS | Other services | 2000 |
| CG Eiendom Kongsberg AS | Real estate | 2026 |
| Challenger Invest AS | Real estate | 2014 |
| Challenger Property AS | Real estate | 2025 |
| Christians Kongsberg AS | Real estate | 2012 |
| Clarion Collection Hotel Kongsberg AS | Hospitality | 2019 |
| Classica Forlag AS | Information & communication | 1991 |
| Claussen AS | Wholesale & retail | 1971 |
| Cleangrip AS | Professional & scientific | 2019 |
| Cleanside AS | Administrative & support | 2021 |
| Cloudburst AS | Information & communication | 2025 |
| Collectin AS | Administrative & support | 2022 |
| Colship AS | Health & social care | 1988 |
| COM2GETHER AS | Wholesale & retail | 2000 |
| Constant Bygg AS | Construction | 2018 |
| Constant Invest AS | Real estate | 2012 |
| Constant Utvikling AS | Real estate | 2016 |
| Conthag AS | Professional & scientific | 2023 |
| Continental Motor AS | Wholesale & retail | 2026 |
| Conven Produkter Da | Wholesale & retail | 2001 |
| Costa Blanca Solhus Norge AS | Real estate | 2005 |
| Coys AS | Real estate | 2006 |
| Creating Waves AS | Information & communication | 2013 |
| Crenova AS | Professional & scientific | 1996 |
| Crossfit Kongsberg AS | Education | 2023 |
| Cårejånni AS | Arts & recreation | 2017 |
| Dag Arne Nilsen Avd. Kongsberg AS | Construction | 2010 |
| Dahlskås Plate Og Sveiseverksted AS | Manufacturing | 2003 |
| Dammen Bygg AS | Construction | 1996 |
| Dampsaga Barnehage AS | Education | 2005 |
| Damåsen Stein AS | Construction | 2006 |
| Dandelion Media AS | | 2025 |
| Darrud Eiendomsdrift AS | Real estate | 2021 |
| Daxaro Eiendom AS | Real estate | 2023 |
| Daxaro Prahms AS | Real estate | 2026 |
| De Fire Små Da | Real estate | 2004 |
| Deltasoft AS | Information & communication | 2001 |
| Depot Moane AS | Wholesale & retail | 1994 |
| Det Norske Myntverket AS | Manufacturing | 2000 |
| Devitech Da | Information & communication | 2011 |
| Devomi Holding AS | | 2026 |
| Didakta Norsk Forlag AS | Information & communication | 1967 |
| Digger AS | Construction | 2018 |
| Digital Capture AS | Administrative & support | 2025 |
| Digital Mediacomm AS | Wholesale & retail | 1998 |
| Din Bilbutikk AS | Wholesale & retail | 2026 |
| Din Taksering AS | Real estate | 2014 |
| Discgolferen Da | Professional & scientific | 2024 |
| Discovery Invest AS | Financial services | 2014 |
| Divcon AS | Construction | 2022 |
| Dokken Takst AS | Real estate | 2023 |
| Douro AS | | 2022 |
| Dow Holding AS | Real estate | 2005 |
| DR Placerville Da | Health & social care | 2002 |
| Draki AS | Professional & scientific | 2025 |
| Dramdal Holding AS | Health & social care | 2005 |
| Drammen Syd Næringseiendom AS | Real estate | 2021 |
| Drammensveien 199 AS | Real estate | 2019 |
| Dreamco Capital AS | | 2025 |
| Dresser-Rand SA | Manufacturing | 2005 |
| Due Gruppen AS | Health & social care | 2003 |
| Duo Elektro AS | Construction | 2024 |
| Duolis AS | Arts & recreation | 2018 |
| Dur & Mold AS | Professional & scientific | 2019 |
| Dyrmyrgata 27 AS | Real estate | 1974 |
| Dyrmyrkroken Eiendom AS | Real estate | 2016 |
| E.T. Skog & Energi AS | Real estate | 2017 |
| Ebitec Invest AS | Manufacturing | 2005 |
| Edelgar AS | Real estate | 2005 |
| Edentri AS | Information & communication | 2019 |
| Edentri Holding AS | | 2025 |
| Eduardox AS | Information & communication | 2020 |
| Eea AS | Wholesale & retail | 2017 |
| Ego Holding AS | | 2005 |
| Ego Tibi AS | | 2020 |