| Bodal Eiendomsutvikling AS | Real estate | 2012 |
| Bokforrådet Ans | Wholesale & retail | 1988 |
| Bolstad Handel AS | Wholesale & retail | 2012 |
| Bona-Holding AS | Other services | 2024 |
| Boo - AS | Construction | 2003 |
| Borg Bygg Og Takst AS | Construction | 2015 |
| Borg CO2 AS | Professional & scientific | 2019 |
| Borg CO2 Terminal AS | Water & waste | 2022 |
| Borg Havn Eiendom AS | Real estate | 2018 |
| Borgar Øst AS | Real estate | 1997 |
| Borgarveien 13 AS | Real estate | 1996 |
| Borge Eiendom AS | Real estate | 1996 |
| Borge Miljøpark AS | Construction | 2019 |
| Borge Trykkluftsenter AS | Manufacturing | 1999 |
| Bos Holding AS | | 2026 |
| Bovio AS | Information & communication | 1995 |
| Bphr AS | Professional & scientific | 2025 |
| BPT Holding AS | Transport & logistics | 2009 |
| Brak AS | Professional & scientific | 2025 |
| Brandr AS | Professional & scientific | 2021 |
| Bricks Beverages AS | Wholesale & retail | 2014 |
| Bristol AS | Wholesale & retail | 2012 |
| Brohuset AS | Real estate | 1987 |
| Brostein Eiendom AS | Real estate | 2020 |
| Brunsbykollen Utvikling AS | Real estate | 2017 |
| Brygger & Skjærgård AS | Other services | 2024 |
| Bryggeriveien 6 AS | Real estate | 1984 |
| Brødr. Bøckmann AS | Real estate | 2013 |
| Brødrene Ødegård Holding AS | Real estate | 2020 |
| Brødrene Ødegård Maskindrift AS | Construction | 2020 |
| Budbilene AS | Transport & logistics | 2022 |
| Budbilene Transportservice AS | Transport & logistics | 2023 |
| Bygg Og Hage Fredrikstad AS | Wholesale & retail | 2024 |
| Byggmester Hans Petter Hovelsen AS | Real estate | 1986 |
| Byggmester Lasse Rasmussen AS | Real estate | 2024 |
| Byggmester Tangen Takst AS | Real estate | 2023 |
| Byggmester Theodorsen AS | Construction | 2015 |
| Båtmannservice AS | Transport & logistics | 1997 |
| Bøckmann Glassindustri AS | Manufacturing | 2020 |
| Børsen Bil Invest AS | Wholesale & retail | 2024 |
| Børsen Holding AS | Real estate | 2000 |
| Calix AS | Professional & scientific | 2025 |
| Camino Forlag AS | Information & communication | 2020 |
| Carbo Invest AS | Real estate | 2013 |
| Carbon Value Technologies AS | Information & communication | 2024 |
| CATCH22 AS | Financial services | 2017 |
| Cemani AS | Real estate | 2020 |
| Childrens International School Fredrikstad AS | Education | 2011 |
| Christianslund Holding AS | Real estate | 2007 |
| Citrinconsult AS | Real estate | 2017 |
| Citykvartalet AS | Real estate | 2024 |
| Classica AS | Professional & scientific | 2024 |
| Clean Skin AS | Health & social care | 2025 |
| Cloke AS | Real estate | 1994 |
| Compodeal AS | Information & communication | 2002 |
| Constellation Cold Logistics Norway AS | Transport & logistics | 2003 |
| Constellation Holding Norway AS | Transport & logistics | 2019 |
| Constellation Transport Norway AS | Transport & logistics | 1991 |
| Copyland AS | Professional & scientific | 2019 |
| Core Utleie AS | Administrative & support | 2022 |
| Costal AS | Financial services | 2012 |
| Crimson Skyfall AS | Information & communication | 2023 |
| Cryonix Data Systems Da | Information & communication | 1999 |
| Culasse AS | Real estate | 2021 |
| Customaid AS | Professional & scientific | 2014 |
| D9 Group AS | | 2025 |
| Dalsegg Invest AS | Real estate | 2015 |
| Daniels Gaards-Service AS | Professional & scientific | 2023 |
| Den Lille Keramikkfabrikken AS | Wholesale & retail | 2026 |
| Denofa Agri AS | Agriculture & fishing | 2021 |
| Denofa Arbeidernes Byggelag AS | Real estate | 1954 |
| Denofa AS | Manufacturing | 2004 |
| Denofa Energi AS | Energy | 2014 |
| Denofa Havn AS | Transport & logistics | 2019 |
| Denofa Industri AS | Manufacturing | 2015 |
| Det Gode Selskab Anita Fon Mathisen Sidsel Lundin Ans | Wholesale & retail | 1999 |
| Developr AS | Information & communication | 2021 |
| Diatech Norway AS | Professional & scientific | 2025 |
| Doozy AS | Professional & scientific | 2022 |
| Dressing Fabrikken AS | Manufacturing | 2012 |
| Drift-Partner AS | Professional & scientific | 2021 |
| Dronningensgate 39 AS | Real estate | 2019 |
| Dronningensgate 45 Sarpsborg AS | Real estate | 2020 |
| Dynamic Integrations AS | Information & communication | 2016 |
| E Bøckmann AS | Financial services | 2013 |
| E&G Bygg Renhold AS | Administrative & support | 2019 |
| E&K Holding AS | | 2001 |
| Eb Hjelp AS | Professional & scientific | 2021 |
| Eccellenza AS | Education | 1995 |
| Edhl Holding AS | | 2018 |
| Eed Invest AS | Real estate | 2020 |
| Egil Syversen Transport AS | Transport & logistics | 2000 |
| Eiendomsutvikler Kjærsund AS | Real estate | 2025 |
| Eikelunden Eiendom AS | Real estate | 2010 |
| Eirik Olsen Holding AS | Financial services | 2007 |
| Eivind Bangors Design Og Tømmerservice AS | Construction | 2016 |
| Ek-Kapital AS | Information & communication | 2019 |
| Eker Defence AS | Wholesale & retail | 2026 |
| Eker Design AS | Professional & scientific | 2001 |
| Eker Estate AS | Real estate | 2023 |