| A Til Å Eiendom AS | Real estate | 2014 |
| A Til Å Entreprenør AS | Construction | 1994 |
| A Til Å Holding AS | Real estate | 2006 |
| A Til Å Utvikling AS | Real estate | 2011 |
| Adm Bygg Og Eiendom AS | Construction | 2019 |
| Admini Ep AS | Hospitality | 2018 |
| Ads Eiendom AS | Real estate | 2007 |
| Ads Holding AS | Wholesale & retail | 2005 |
| Ads Invest AS | Real estate | 2021 |
| Ads Sentrum AS | Real estate | 2009 |
| Akzo Nobel Industrial Chemicals BV | Wholesale & retail | 2004 |
| Alfheim Trading AS | | 2023 |
| Alseth Maskin AS | Construction | 2023 |
| Andersm Holding AS | | 2019 |
| Angen Service AS | Construction | 2021 |
| Annemor Holding AS | | 2025 |
| Apo Holding AS | Financial services | 2009 |
| Arena Kompetanse AS | Health & social care | 1991 |
| Arnfinn Sauro AS | | 2005 |
| AS Rjukan Forretningsbygg | Real estate | 1969 |
| Assistco AS | Wholesale & retail | 1991 |
| Assistco Eiendom AS | Real estate | 1989 |
| Atb-Nett AS | Information & communication | 2009 |
| Auke AS | Manufacturing | 2025 |
| Auke Fertilizer AS | Water & waste | 2022 |
| Ausland Holding AS | | 2020 |
| Ballonghallen AS | Real estate | 2001 |
| Baut AS | Professional & scientific | 2018 |
| Bedriftsvakta AS | Professional & scientific | 2019 |
| Bhank! Studios AS | Information & communication | 2024 |
| Bibesto AS | Information & communication | 2019 |
| Bistro Bygget AS | Hospitality | 2023 |
| Bjarne Thorud Farvehandel AS | Wholesale & retail | 1979 |
| Bjørn Berge AS | Other services | 1993 |
| Bjørn Berge Bensinstasjon AS | Wholesale & retail | 1998 |
| Bjørtuft Eiendom AS | Real estate | 2023 |
| Bjørtuft Glasservice AS | Wholesale & retail | 2018 |
| Bli Holding AS | | 2006 |
| Blomsterbutikken Rjukan AS | Wholesale & retail | 2012 |
| Blomstergutta AS | Real estate | 2013 |
| Blått Til Lyst AS | Wholesale & retail | 1994 |
| Bolsbasic AS | Education | 2023 |
| Brdr Hansen Transport AS | Transport & logistics | 2022 |
| Brødrene Hansen AS | Transport & logistics | 1992 |
| Brødrene Øverland Holding AS | Real estate | 2016 |
| Buddy's Pub Da | Hospitality | 2011 |
| Buypropnorway AS | Professional & scientific | 2025 |
| Byggmester Brede W. Nørstebø AS | Construction | 2024 |
| Byggmesteren AS | Real estate | 2011 |
| Byhjørnet AS | Construction | 2010 |
| Chase Holding AS | Transport & logistics | 2023 |
| Christian Sør-Reime Holding AS | | 2023 |
| CMD Montage AS | Professional & scientific | 2019 |
| CO2PILOT AS | Information & communication | 2022 |
| Codesign AS | Professional & scientific | 2011 |
| Context Ochre AS | Professional & scientific | 2025 |
| Dong Fang Restaurant AS | Hospitality | 2012 |
| Elektro-Kjøl Spesialisten AS | Other services | 1990 |
| Elkjøp Tinn AS | Wholesale & retail | 1995 |
| Em Bygg- Tre- Mur- Betong Da | Construction | 2006 |
| Ep Eiendom AS | Real estate | 2005 |
| Eyde Kraft AS | Hospitality | 2020 |
| Fitnesspoint Rjukan Treningssenter AS | Arts & recreation | 2025 |
| Fjellab AS | Professional & scientific | 2024 |
| Fjellerud Eiendom AS | Real estate | 2015 |
| Fjellvåken AS | Transport & logistics | 1998 |
| Flaata Eiendom AS | Real estate | 2006 |
| Flaata Stable AS | Agriculture & fishing | 2014 |
| Flathegna AS | Real estate | 1993 |
| Frisør Benny Ofstad AS | Other services | 2005 |
| Fun Fuel AS | Wholesale & retail | 2020 |
| G-Mat Rjukan AS | Wholesale & retail | 1998 |
| Gausta Booking AS | Hospitality | 2026 |
| Gausta Destinasjonsutvikling AS | Administrative & support | 2025 |
| Gausta Forvaltning AS | Real estate | 2022 |
| Gausta Hytteutleie AS | Real estate | 2019 |
| Gausta Kvitåvatn Turistservice AS | Arts & recreation | 1990 |
| Gausta Ski & Resort AS | Hospitality | 2007 |
| Gausta View AS | Real estate | 2017 |
| Gausta View Hospitality AS | Hospitality | 2023 |
| Gaustabanen AS | Transport & logistics | 1992 |
| Gaustabanen Eiendom AS | Real estate | 2020 |
| Gaustablikk Eiendom AS | Real estate | 2007 |
| Gaustaekspressen AS | Transport & logistics | 2020 |
| Gaustafoten Eiendom AS | Real estate | 2022 |
| Gaustahytten AS | Real estate | 2022 |
| Gaustatoppen AS | Real estate | 2016 |
| Gaustatoppen Basecamp AS | Real estate | 2021 |
| Gaustatoppen Eiendomsutvikling AS | Real estate | 2006 |
| Gaustatoppen Fjellhytter AS | Real estate | 2015 |
| Gaustatoppen Hilltop AS | Real estate | 2017 |
| Gaustatoppen Holding AS | Real estate | 1995 |
| Gaustatoppen Hyttegrend AS | Real estate | 2006 |
| Gaustatoppen Slopestyle AS | Real estate | 2018 |
| Gear Tech Norway AS | Professional & scientific | 2024 |
| Gondolin Holding AS | | 2024 |
| Gosh AS | | 2014 |
| Graceland AS | Wholesale & retail | 1987 |
| Granlund Holding AS | Hospitality | 2005 |
| Grumheden Holding AS | Professional & scientific | 2008 |