| 654 M.O.H AS | Wholesale & retail | 2005 |
| Ace of Hearts AS | Administrative & support | 2026 |
| Adm Mobile AS | Wholesale & retail | 2022 |
| Advokathuset Røros AS | Professional & scientific | 2022 |
| Aircraft Solutions AS | Construction | 2013 |
| Aj Sandnes Bygg AS | Construction | 2006 |
| Aktiviteten Treningssenter AS | Arts & recreation | 1999 |
| Al Røros Slakteri | Manufacturing | 1968 |
| Amlin AS | | 2026 |
| Amneus Boghandel AS | Wholesale & retail | 1996 |
| Annmeste AS | | 2019 |
| Ans Røros Vaktselskap | | 1990 |
| Ans Skotts Maskin | Construction | 1990 |
| Arbeidets Rett AS | Information & communication | 1983 |
| Arbeidsbiler AS | Wholesale & retail | 2017 |
| Aren Holding AS | Real estate | 2005 |
| Arena Røros AS | Hospitality | 2017 |
| Arnt Langen Holding AS | | 2019 |
| Arnte Holding AS | Financial services | 2017 |
| Artisans of Røros AS | Professional & scientific | 2014 |
| AS Fæmund | Transport & logistics | 1886 |
| Atelier Fjellpryd Blomster Og Begravelsesbyrå AS | Wholesale & retail | 1996 |
| Aventus Green Technology AS | Energy | 2019 |
| BA20 Invest AS | | 2022 |
| Bakke Consulting AS | Professional & scientific | 2000 |
| Bari Restaurant & Pizzeria AS | Hospitality | 2021 |
| Bergan Bruk AS | Other services | 2023 |
| Bergh-Bendixvold Holding AS | | 2026 |
| Bergmannsgata 11 AS | Real estate | 2021 |
| Bergmannsgata 3 AS | Real estate | 2013 |
| Bergmannsgata 34 AS | Real estate | 2024 |
| Bergmannsgata 6 AS | Real estate | 2003 |
| Bergstaden Elektro Holding AS | Construction | 2020 |
| Bergstaden Rengjøring AS | Administrative & support | 2021 |
| Bergstaden Servicesenter AS | Wholesale & retail | 2019 |
| Bergstaden Taxi Og Turvogn AS | Transport & logistics | 2020 |
| Bergstadens Hotel AS | Hospitality | 2011 |
| Bergstadens Hotel Eiendom AS | Real estate | 1933 |
| Bergstadens Regnskapskontor AS | Professional & scientific | 1970 |
| Betong Røros Holding AS | | 2025 |
| Bevegelsen Forlag AS | Information & communication | 2022 |
| Biotop AS | Professional & scientific | 2025 |
| Bjuda På AS | Arts & recreation | 2017 |
| BKG Utvikling AS | Professional & scientific | 2018 |
| Blikkenslager Tønset AS | Construction | 2013 |
| Bokero Holding AS | Real estate | 2000 |
| Booknorway AS | Information & communication | 2004 |
| Borgos Holding AS | Construction | 2020 |
| Broen Verksted AS | Other services | 2013 |
| Butikk 236 Erik Og Rolf Magnus's Ans | Wholesale & retail | 2006 |
| Byehjørnet AS | Real estate | 1990 |
| Byggtek Røros AS | Professional & scientific | 2025 |
| Bensin- og Servicesentret A/S | Wholesale & retail | 1982 |
| CH Eiendom AS | Real estate | 2019 |
| Chanel Design AS | Manufacturing | 2023 |
| Compenso Eiendom AS | Real estate | 2010 |
| Compenso Holding AS | Wholesale & retail | 2010 |
| Condestra Norge AS | | 2005 |
| Da-Tec Ans | Wholesale & retail | 2001 |
| Ditt Kreative Rom AS | Professional & scientific | 2026 |
| Doktortjønna Eiendom AS | Real estate | 2005 |
| Eiendomsmegleren I Fjellregionen AS | Real estate | 2005 |
| Eki Eiendom AS | Real estate | 2026 |
| Elektropunkt AS | Construction | 2023 |
| Elektropunkt Holding AS | Construction | 2023 |
| Elven Invest AS | Administrative & support | 2005 |
| Engveien 2 Tynset AS | Wholesale & retail | 2008 |
| Ericson Holding AS | Real estate | 2000 |
| Erzscheidergården AS | Real estate | 2000 |
| Esø Holding AS | Financial services | 2010 |
| Etate Holding AS | Real estate | 2021 |
| Euforia AS | Other services | 2007 |
| Evavolds Maskin AS | Construction | 1976 |
| Experience Lyd Da | Arts & recreation | 2007 |
| Explore Røros AS | Administrative & support | 2016 |
| Eystein Hindklev AS | Wholesale & retail | 2024 |
| Femundløpet AS | Arts & recreation | 2010 |
| Feragen Holding AS | Construction | 2024 |
| Feragen Maskin AS | Construction | 2009 |
| Feragen Vannverk AS | Water & waste | 2019 |
| Fidel Holding AS | | 2024 |
| Fjell-Ljom AS | Information & communication | 1987 |
| Fjellbjørk AS | Wholesale & retail | 1989 |
| Fjellheimen Forlag SA | Information & communication | 1994 |
| Fjellrosa Spa AS | Other services | 2024 |
| Fjellrypas Eiendom AS | Administrative & support | 2017 |
| Fjellrypas Holding AS | Administrative & support | 2017 |
| Fjellsten Holding AS | | 2026 |
| Folkemusikk Røros AS | Administrative & support | 2019 |
| Fondahuset AS | Arts & recreation | 2023 |
| Form Til Fjells AS | Professional & scientific | 2003 |
| Fotterapeut Kari Ryttervoll AS | Health & social care | 2022 |
| Frian AS | Professional & scientific | 1993 |
| Frode Sjøvold AS | Administrative & support | 2005 |
| Frost Lade AS | Wholesale & retail | 2021 |
| Fruvollen AS | Real estate | 2013 |
| G & H Eiendom AS | Real estate | 2009 |
| Galåen Naturbarnehage AS | Education | 2004 |
| Galåen Samdrift Da | Agriculture & fishing | 2005 |
| Galåen Transport AS | Transport & logistics | 1996 |