| 360 Consult AS | Professional & scientific | 2024 |
| 59'NORD Omsorg Og Service AS | Construction | 2017 |
| A Venture AS | Professional & scientific | 2014 |
| A&E Company AS | Wholesale & retail | 2022 |
| Abm Holding AS | Real estate | 2015 |
| Abs Fredrikstad AS | Construction | 2012 |
| Afzali Consulting AS | Information & communication | 2024 |
| Agenta Group AS | Wholesale & retail | 2006 |
| Agt Holding AS | Financial services | 2005 |
| Aifin Holding AS | | 2021 |
| Andersen Engseth Eiendom AS | Real estate | 2016 |
| Andersen Og Dalstrøm Transport AS | Transport & logistics | 2002 |
| Anvema AS | Wholesale & retail | 2009 |
| Arken AS | Real estate | 1997 |
| Art and Second-Hand Shop AS | Wholesale & retail | 2022 |
| AS Elektro Bilxtraverksted | Other services | 1979 |
| AS Kafra | Construction | 2018 |
| Ask Helse AS | Health & social care | 2024 |
| Autoleie Østfold AS | Administrative & support | 2009 |
| Bad AS | Construction | 2025 |
| Bakkal Østfoldhallene AS | Wholesale & retail | 2025 |
| Ballongshow AS | Hospitality | 2016 |
| Bare Bolig Og Eiendom AS | Real estate | 2013 |
| Barnehagevikarene AS | Administrative & support | 2021 |
| Battenfeld Sverige AB Norsk Avd Av Utenlandsk Foretak Nuf | Wholesale & retail | 1995 |
| Bazar Matvare AS | Wholesale & retail | 2024 |
| BB Bygg AS | Construction | 2024 |
| Beha Group AS | Wholesale & retail | 2019 |
| Beha Target AS | Wholesale & retail | 2000 |
| Benny Fransen Holding AS | | 2026 |
| Bertel O Steen Østfold AS | Other services | 1978 |
| Bifrost Forvaltning AS | | 2024 |
| Bilhagen Fredrikstad AS | Wholesale & retail | 2021 |
| Bilsalong 1 AS | Wholesale & retail | 2017 |
| Bio-San Ans | | 1990 |
| Biopharma AS | Manufacturing | 2000 |
| Biosan AS | Manufacturing | 1995 |
| Bjørn Hansen Holding AS | Wholesale & retail | 2006 |
| Bjørn Inge Og Arnulf Rostad Da | Agriculture & fishing | 1999 |
| Bjørnengveien 11 AS | Real estate | 2023 |
| Bjørnengveien 15 AS | Real estate | 2023 |
| Bjørnengveien 16 AS | Real estate | 2016 |
| Bjørnengveien 6 AS | Real estate | 2025 |
| Blakkestad Andersen Group AS | Construction | 2012 |
| Blakkestad Andersen Invest AS | Real estate | 2020 |
| Blakkestad Holding AS | Construction | 2012 |
| Blekkspruten Ans | Arts & recreation | 1994 |
| Blekkspruten Østfold AS | Arts & recreation | 2013 |
| Blikkenslager Fahlstrøm AS | Construction | 2023 |
| Blockchain Academy AS | Education | 2022 |
| BLOMQVIST IMPORT ANS Kjersti Engseth Blomqvist og Øivind Blomqvist | | 1987 |
| BM Auto AS | Wholesale & retail | 2024 |
| Borg Consulting AS | Professional & scientific | 2012 |
| BOSS1 AS | Construction | 2011 |
| Bottega Nord AS | Wholesale & retail | 2025 |
| Bredmyra Eiendom AS | Wholesale & retail | 2008 |
| BRH Eiendom AS | Real estate | 2011 |
| Bråthen Mur Og Flis AS | Construction | 2005 |
| Brødr Iversby AS | Construction | 1987 |
| Byggerkån AS | Construction | 2021 |
| Byggerkån Group Holding AS | | 2022 |
| Byggkompaniet Østfold AS | Construction | 1994 |
| Byhaven Invest AS | | 2023 |
| Båtpartner Holding AS | Manufacturing | 2020 |
| Cantona Holding AS | | 2020 |
| Chess AS | Professional & scientific | 2015 |
| Citrox Da | Information & communication | 2005 |
| Comito AS | Professional & scientific | 2013 |
| Cook Norge AS | Wholesale & retail | 2010 |
| Crown Norge AS | Wholesale & retail | 2005 |
| Cafe Royal AS | Hospitality | 1990 |
| D.A Hodl AS | | 2022 |
| Dammensvika Prosjekt AS | Real estate | 2020 |
| Datatrees AS | Information & communication | 2020 |
| Descartes Systems (Norway) AS | Information & communication | 1989 |
| Designverksted AS | Professional & scientific | 2021 |
| Di Team AS | Transport & logistics | 2022 |
| Digimek Da | Professional & scientific | 2001 |
| Dikeveien 20 AS | Real estate | 2026 |
| Dikeveien 38 AS | Real estate | 2012 |
| Dikeveien 44 AS | Real estate | 2016 |
| Dikeveien 52 Eiendom AS | Real estate | 2011 |
| Dikeveien 55 AS | Real estate | 2021 |
| Din Thaimat AS | Hospitality | 2021 |
| Ditt Eiendomsprosjekt AS | Real estate | 2024 |
| Ditt Hårstudio AS | Other services | 2013 |
| DMR AS | Real estate | 2012 |
| Drive Time Trafikkskole AS | Education | 2015 |
| Dør & Vindu AS | Wholesale & retail | 2018 |
| Dør & Vindu Gruppen AS | Wholesale & retail | 2005 |
| E-Dart Norway AS | Arts & recreation | 2026 |
| E.F Holding AS | Real estate | 1979 |
| Eco Scandinavia AS | Wholesale & retail | 2012 |
| Edelmetallstøperiet AS | Manufacturing | 2001 |
| Eiendom 88 AS | Real estate | 2024 |
| Einar Nilsen Og Sønn Transport AS | Transport & logistics | 2014 |
| Eivind Engseth AS | | 1977 |
| Eivind Engseth Entreprenør AS | Construction | 2016 |
| Ekte Tre AS | Wholesale & retail | 2019 |
| Elem Invest AS | Real estate | 2017 |