| Buro Ops AS | Information & communication | 2023 |
| Butikkdrift Altarshan AS | Wholesale & retail | 2026 |
| Butler Trading Da | Wholesale & retail | 2000 |
| Buus Jensen & Co Ans | | 1986 |
| BVS Gruppen AS | Information & communication | 2026 |
| BVS Takst AS | Real estate | 2026 |
| By Hvesser AS | Professional & scientific | 2018 |
| Bygg & Håndverkstjenester AS | Construction | 2022 |
| Bygg Brøderne Sørensson AB | Construction | 2000 |
| Bygg Entreprenør Norge AS | Construction | 2012 |
| Bygg Hjem Og Hobby AS | Real estate | 1990 |
| Bygg Litt AS | Real estate | 2022 |
| Bygg Og Hjem AS | Construction | 2024 |
| Bygg Og Land AS | Construction | 2019 |
| Bygg Spar AS | Wholesale & retail | 1985 |
| Byggmester Aasgaard AS | Construction | 2023 |
| Byggmester Bjørn Einar Hanssen AS | Construction | 2003 |
| Byggmester Rune Pettersen AS | Construction | 2004 |
| Byggmester Svenberg AS | Construction | 2021 |
| Byggmester Ulf Johannessen AS | Construction | 2005 |
| Byggmester Vik AS | Construction | 2021 |
| Byggmestrene Knudsen Og Askautrud AS | Construction | 2018 |
| Byggpartner Moss AS | Construction | 2026 |
| Bylegene Moss AS | Health & social care | 2017 |
| Byma Holding AS | | 2024 |
| Bragernæs Skotøimagazin J A Magnussen AS | Wholesale & retail | 1976 |
| Bädd & Bad AB | Wholesale & retail | 2005 |
| Båndtech AS | Manufacturing | 2016 |
| Båtkalesje Og Tekstil AS | Manufacturing | 2024 |
| Båtutstyr AS | Wholesale & retail | 1982 |
| Bøhm Eiendom AS | Real estate | 2008 |
| Bølgen 808 AS | Real estate | 2011 |
| Bør Invest AS | Real estate | 2007 |
| Børges Fotofabrikk AS | Professional & scientific | 2026 |
| Børnich Holding AS | Real estate | 2023 |
| Børslett AS | Health & social care | 2013 |
| Bøtteblikk AS | | 2023 |
| C Marine Holding AS | | 2021 |
| C. Hauge Holding AS | Construction | 2021 |
| C.J.Viken Holding AS | | 2023 |
| Cab Holding AS | Financial services | 2005 |
| Caet Holding AS | Wholesale & retail | 2008 |
| Cafe Violet AS | Hospitality | 2020 |
| Calder Design Studio AS | Arts & recreation | 2023 |
| Caligula Holding AS | Health & social care | 2012 |
| Camblift AS | Wholesale & retail | 2024 |
| Campino Kebab House AS | Hospitality | 2012 |
| Cap Invest & Forvaltning AS | | 2024 |
| Caravelle Tours AS | Administrative & support | 2007 |
| Carbon - G AS | Wholesale & retail | 2026 |
| Carelp AS | Information & communication | 2022 |
| Carlberghome Styling AS | Professional & scientific | 2019 |
| Carlbergveien 7 AS | Real estate | 2006 |
| Carona AS | Real estate | 2005 |
| Casa Puente AS | | 2023 |
| Casey Holding AS | | 2026 |
| Casino AS | Real estate | 1979 |
| Casino Drift AS | Real estate | 1993 |
| Catering Service AS | Hospitality | 1984 |
| Cato-Eiendom AS | Hospitality | 2011 |
| CB VVS AS | Construction | 2025 |
| CCL Property AS | Real estate | 2017 |
| Cefyr AS | Information & communication | 2022 |
| Celest AS | Wholesale & retail | 2025 |
| Cemka AS | Information & communication | 2012 |
| Central Lounge AS | Professional & scientific | 2025 |
| Centrio AS | Information & communication | 2025 |
| Centrum Eiendom AS | Real estate | 1993 |
| Centrum Eiendom Østfold AS | Real estate | 2011 |
| Cetero AS | | 2016 |
| Cevent AS | Arts & recreation | 2020 |
| CH Hersleth Holding AS | | 2017 |
| Charter-Tur AS | Administrative & support | 2002 |
| Chickens Only Group AS | Hospitality | 2023 |
| Childrens International School Moss AS | Education | 2014 |
| Chili Networks AS | Information & communication | 2012 |
| Chilimobil AS | Information & communication | 2011 |
| Chiller Norge AS | Construction | 2010 |
| Christerinho Holding AS | Information & communication | 2018 |
| Christins Fotterapi AS | Health & social care | 2016 |
| Circular Ways AS | Professional & scientific | 2018 |
| Circular Ways Design AS | Professional & scientific | 2022 |
| Circular Ways Holding AS | | 2022 |
| City Forest AS | | 2020 |
| City Frisør & Barber AS | Other services | 2017 |
| City Møbler Moss AS | Wholesale & retail | 2025 |
| City Syd Klinikken AS | Health & social care | 2016 |
| Citypark AS | Real estate | 2018 |
| Claussen Investering AS | | 2023 |
| Cleanosol AS | Real estate | 2018 |
| Clever Holding AS | Information & communication | 2024 |
| Clever IT AS | Information & communication | 2023 |
| Clips AS | Other services | 2022 |
| Cloudahead AS | Information & communication | 2025 |
| Clovera Ans | Information & communication | 2023 |
| CLP Eiendom AS | Real estate | 2022 |
| Club House AS | Information & communication | 2018 |
| Cnc-Protek AS | Manufacturing | 2018 |
| Co-Creator AS | Professional & scientific | 2015 |
| Coach Link Da | Transport & logistics | 2013 |