| C.H.Bygg Og Service AS | Construction | 2018 |
| C.M. Holding AS | Real estate | 2015 |
| Ca Eiendom AS | Real estate | 2026 |
| Caddy AS | Financial services | 2005 |
| Cafe 1910 AS | Hospitality | 2025 |
| Camah Eiendom AS | Real estate | 2025 |
| Camah Holding AS | Real estate | 1997 |
| Cancan AS | Professional & scientific | 2014 |
| Cancan Live AS | Professional & scientific | 2019 |
| Capricorn Invest AS | | 1997 |
| CARE1 AS | Other services | 2016 |
| Carrocar AS | Wholesale & retail | 2006 |
| Centrum Investment AS | Financial services | 2005 |
| Cerwonol Norge AS | Construction | 1990 |
| Chainsaw Cowboys Da | Arts & recreation | 2010 |
| Childrens International School Sarpsborg AS | Education | 2018 |
| City Hub AS | Real estate | 2023 |
| Clairon X AS | | 2025 |
| Class Holding AS | Real estate | 2008 |
| Clay & Taylor AS | Real estate | 2019 |
| Clench AS | Information & communication | 2025 |
| Clipper Norge AS | Wholesale & retail | 1999 |
| Cltre Norge AS | Professional & scientific | 2008 |
| Cml`S Maritime Art Company Ans | Arts & recreation | 1996 |
| Coegi Invest AS | Wholesale & retail | 2020 |
| Commnet AS | Information & communication | 2000 |
| Concensus Eiendom AS | Real estate | 2009 |
| CONT1T AS | Wholesale & retail | 2008 |
| Corob Scandinavia AB Nuf | Wholesale & retail | 1997 |
| Cosmovita AS | Wholesale & retail | 2023 |
| Cottage AS | Real estate | 2020 |
| Cottage Eiendom AS | Real estate | 2020 |
| Creativ Company AS | Wholesale & retail | 2007 |
| Curasenteret AS | Health & social care | 2020 |
| Cut'N Go Sarpsborg AS | Other services | 2023 |
| Dahle Eiendom Drift AS | Real estate | 2016 |
| Dahle Eiendom Holding AS | Real estate | 1981 |
| Dahle Holding AS | Other services | 2016 |
| Dahle Holding Invest AS | Real estate | 2022 |
| Dahle Og Sørlie Eiendom AS | Real estate | 2017 |
| Dahles Auto AS | Other services | 2015 |
| Dahles Auto Sarpsborg AS | Other services | 1968 |
| Dahles Bilutleie AS | Administrative & support | 2003 |
| Daku Eiendom AS | Real estate | 2014 |
| DBK AS | Wholesale & retail | 2012 |
| De Heldige AS | Arts & recreation | 2016 |
| Degerdal Legetjenester AS | Health & social care | 2017 |
| Delebekk Holding AS | | 2022 |
| Deli Eiendom AS | Real estate | 2014 |
| Delta-Holding AS | | 2025 |
| Dermasykepleier AS | Health & social care | 2018 |
| Dermatologisk Poliklinikk Sarpsborg AS | Health & social care | 2018 |
| Design Av Elisabeth AS | Wholesale & retail | 2022 |
| Det Grønne Skiftet AS | Construction | 2018 |
| DG Utvikling AS | Real estate | 2026 |
| DG80 Invest AS | | 2025 |
| Dickens Sarpsborg AS | Hospitality | 2025 |
| Digirett AS | Professional & scientific | 2025 |
| Digital-Servicebook.Com AS | Information & communication | 2025 |
| Digleefy AS | Manufacturing | 2020 |
| Dikeveien 27-29 AS | Real estate | 2018 |
| Dikeveien 50 Eiendom AS | Real estate | 2013 |
| Din Klinikk Sarpsborg Da | Real estate | 2008 |
| Dino´S Brasserie AS | Hospitality | 2025 |
| Diomant Holding AS | | 2025 |
| Diversifisert AS | Professional & scientific | 2022 |
| Dof Erstatningssøksmålet AS | Professional & scientific | 2024 |
| Doffen Modulhus AS | Real estate | 2021 |
| Dolor AS | Education | 2011 |
| Dovreskogen Eiendom AS | Real estate | 2021 |
| Downtown Pizza & Kebab AS | Hospitality | 2025 |
| DP Solutio AS | Information & communication | 2019 |
| DPC Eiendom AS | Hospitality | 2008 |
| Dukan AS | Wholesale & retail | 2012 |
| Duloshop AS | Information & communication | 2026 |
| Dusen AS | | 2024 |
| Dynamic Relations AS | Professional & scientific | 2023 |
| Dyrendalsveien 13 AS | Real estate | 2010 |
| Dyrop Holding AS | | 2026 |
| Dør & Vindu Sarpsborg AS | Wholesale & retail | 2019 |
| E&K-M Holding AS | | 2018 |
| E. Messel Holding AS | | 2024 |
| Ebf Invest AS | | 2005 |
| Eco Systemvask AS | Administrative & support | 2025 |
| Edge Property AS | Real estate | 2017 |
| Eds Byggmontage | Construction | 2015 |
| Edvarts Pubdrift AS | Hospitality | 2019 |
| Ege Utvikling AS | Real estate | 2022 |
| Egil Pedersen AS | Construction | 1996 |
| Eighteen AS | Hospitality | 2019 |
| Eiklia Eiendom AS | Real estate | 2026 |
| Eine Eiendom AS | Real estate | 2021 |
| Eiton AS | | 2005 |
| Ekblad Og Olsen Eiendom Ans | Real estate | 2004 |
| El-Tech AS | Construction | 2020 |
| El-Tjenesten AS | Construction | 2012 |
| Eldgaard II AS | Hospitality | 1986 |
| Elektro 247 AS | Information & communication | 2022 |
| Elena Nikitenkova AS | Health & social care | 2024 |
| Elin Tvete Eiendom AS | Real estate | 2015 |