| Båthuslag 3 SA | Other services | 1967 |
| Båthuslag II Smalsund SA | Real estate | 1958 |
| Båtservice Contracting AS | Manufacturing | 2022 |
| Båtservice Holding AS | Manufacturing | 2005 |
| Båtservice Mandal Verft AS | Manufacturing | 1989 |
| Børufsen Holding AS | | 2020 |
| C&C Holding AS | | 2021 |
| Ca Po AS | Administrative & support | 2005 |
| Caddyshack AS | Wholesale & retail | 2014 |
| Candide AS | | 2020 |
| Cape Cod AS | Wholesale & retail | 2024 |
| Carinas-Salong AS | Other services | 2012 |
| Carl a Leschbrandt AS | Wholesale & retail | 1976 |
| Cayenne Holding AS | Wholesale & retail | 2005 |
| CB Prosjekt AS | Construction | 2020 |
| CC Invest AS | Real estate | 2007 |
| Cea Mekanisk AS | Manufacturing | 2013 |
| Cecilie H AS | Wholesale & retail | 2018 |
| Celvic AS | Professional & scientific | 2018 |
| Cento AS | Manufacturing | 2025 |
| Cewave AS | Professional & scientific | 2017 |
| Check Point AS | Wholesale & retail | 1990 |
| Circuit Capital AS | | 2022 |
| CKJ AS | Financial services | 2005 |
| Come Ohm AS | Professional & scientific | 2026 |
| Compositeur AS | Real estate | 2008 |
| Concon AS | Construction | 1991 |
| Concord Frisør AS | Other services | 2014 |
| Corporate Cup AS | Administrative & support | 2018 |
| Cretec AS | Professional & scientific | 2006 |
| Crypto AS | Wholesale & retail | 2017 |
| CV Eiendom Og Utleie AS | Real estate | 2019 |
| Daasvatn Prosjekt AS | Professional & scientific | 2017 |
| Dalbo Eiendom AS | Real estate | 2007 |
| Dalen Elektro AS | Construction | 2021 |
| Daleveien 107 AS | Real estate | 2014 |
| Dandug AS | Hospitality | 2012 |
| Danseglede AS | Education | 2024 |
| Dansig AS | Hospitality | 2024 |
| Data Partner Mandal Ans | Other services | 2000 |
| DD Gaarden Drift AS | Hospitality | 2024 |
| Deepend AS | Real estate | 2017 |
| Dental Sør AS | Wholesale & retail | 1988 |
| Designhager AS | Professional & scientific | 2009 |
| Det Hvite Hus Ved Havet AS | Real estate | 1994 |
| Diesel Service AS | Manufacturing | 2009 |
| Difai AS | Information & communication | 2023 |
| Digifish AS | Information & communication | 2011 |
| Digiserv AS | Wholesale & retail | 2018 |
| Digitek AS | Information & communication | 2019 |
| Digre Prosjekt Da | Wholesale & retail | 2009 |
| Ditt Minilager AS | Real estate | 2023 |
| DK Inox Norge AS | Manufacturing | 2025 |
| DK Offshore AS | Mining & quarrying | 2025 |
| Doneheia 114A AS | Real estate | 2012 |
| Doneheia Bygg & Utleie AS | Real estate | 2022 |
| Doneheia Eiendom AS | Real estate | 2004 |
| Dueteigen Holding AS | Real estate | 2012 |
| Dynamitten AS | Hospitality | 2023 |
| Dypheimr AS | Information & communication | 2025 |
| Dyrstad Bygg Og Maskin AS | Construction | 2014 |
| Dyrstad-Invest AS | Financial services | 2012 |
| Dyvika Nord Renseanlegg SA | Water & waste | 2022 |
| E Solaas Holding AS | Construction | 2019 |
| E&G Noddeland Holding AS | | 2025 |
| E.J Holding AS | Financial services | 2005 |
| E.L.K. Larsen Invest AS | Financial services | 2018 |
| E.P. Holding AS | Real estate | 2005 |
| Eal AS | | 2026 |
| Ebitu AS | | 2020 |
| Ebtechnology AS | Information & communication | 2016 |
| Edb Avdelingen Sør AS | Other services | 1994 |
| Edgars Bakeri AS | Manufacturing | 1998 |
| Egeland & Andersen Holding AS | Wholesale & retail | 2006 |
| Ehi Norge AS | Real estate | 2007 |
| Ehr Invest AS | | 2020 |
| Eiendomselskapet Sommerkroveien 32 AS | Real estate | 1999 |
| Eiendomshjelp AS | Real estate | 2015 |
| Eigebrekk Øst Kloakk AS | Water & waste | 2007 |
| Eikaas Drift AS | Wholesale & retail | 2011 |
| Eikaas Eiendom AS | Real estate | 2007 |
| Eiken Invest AS | Professional & scientific | 1983 |
| Eikon Allservice AS | Administrative & support | 2024 |
| Eikså Invest AS | Construction | 2005 |
| Eilas Kjøkken AS | Hospitality | 2024 |
| Eina AS | Financial services | 2006 |
| Eivind Eigebrekk AS | Construction | 2001 |
| Eja AS | | 2016 |
| Ekconsult AS | Professional & scientific | 2024 |
| El-Pec AS | Construction | 1997 |
| Elektro Sør AS | Construction | 1999 |
| Elektro Sør Eiendom AS | Real estate | 1980 |
| Elektro Sør Holding AS | Construction | 1997 |
| En Invest AS | Real estate | 2005 |
| Endling AS | Professional & scientific | 2025 |
| Energihuset Eiendom Mandal AS | Real estate | 2023 |
| Energihuset Holding AS | Professional & scientific | 2019 |
| Energy Manager AS | Information & communication | 2013 |
| Enøk Total AS | Professional & scientific | 2013 |
| Enøk Total Elektro AS | Construction | 2000 |