| Casa Nostra AS | Real estate | 2021 |
| Cato Thorsen Utleie AS | Real estate | 2025 |
| Ceca SA | Construction | 2000 |
| Cehirdie Holding AS | | 2023 |
| Celeritas AS | Hospitality | 2018 |
| Cell Magic Limited Nuf | Information & communication | 2024 |
| Cem Bulk Management AS | Transport & logistics | 1995 |
| Chainbrium AS | Administrative & support | 2023 |
| Chambolle Invest AS | Wholesale & retail | 2020 |
| Chamin AS | Other services | 2024 |
| Chill Music AS | Arts & recreation | 2013 |
| China Palace Haugesund AS | Hospitality | 2015 |
| CHR Baardsen & Søn AS | Wholesale & retail | 2003 |
| Christina Eilertsen AS | Education | 2024 |
| Christina Modell AS | Wholesale & retail | 1963 |
| Cibo AS | Hospitality | 2021 |
| CIC Operations Haugesund AS | Hospitality | 2019 |
| CIC Operations Haugesund Park Pluss AS | Hospitality | 2023 |
| Cidster H AS | | 2026 |
| Circupolytech B.V. Nuf | Professional & scientific | 2025 |
| Cityboat AS | Transport & logistics | 2026 |
| CK Eiendom AS | Real estate | 2005 |
| CK Invest AS | Real estate | 2011 |
| Classic Garden Apartments AS | Real estate | 2020 |
| Cleantank AS | Professional & scientific | 2022 |
| Clinic 55 AS | Health & social care | 2025 |
| Clipper Group | Wholesale & retail | 2006 |
| Club Partner AS | Hospitality | 2004 |
| CMC Electric Aps | Administrative & support | 2001 |
| Cmi Forvaltning AS | Real estate | 1986 |
| CMM Cognition Matters Management AS | Real estate | 2007 |
| Cmo AS | Mining & quarrying | 2011 |
| CNS Invest II AS | Real estate | 2006 |
| Cojack AS | Professional & scientific | 2019 |
| Compass AS | Real estate | 2006 |
| Comvik AS | | 2020 |
| Con Invest AS | Real estate | 1998 |
| Concordia Capo AS | Transport & logistics | 1996 |
| Concordia Consulting AS | Professional & scientific | 2020 |
| Concordia Foss AS | Transport & logistics | 1996 |
| Concordia Star AS | Transport & logistics | 1996 |
| Condor Invest AS | Wholesale & retail | 2015 |
| Condor Sentrum AS | Wholesale & retail | 2020 |
| Connectit AS | Wholesale & retail | 2005 |
| Consus AS | | 2005 |
| Containercarrier I AS | Transport & logistics | 2005 |
| Continentel Tug Holding BV | | 1997 |
| Conturklinikken AS | Health & social care | 2015 |
| Coral Tankers GmbH Nuf | Transport & logistics | 2020 |
| Cornos AS | Wholesale & retail | 2008 |
| Costra AS | Real estate | 2005 |
| Countach Montasje AS | Construction | 2026 |
| Crossfit Verftet AS | Arts & recreation | 2021 |
| Crudecorp AS | Administrative & support | 2007 |
| Crush Concept AS | Wholesale & retail | 2010 |
| Crush II AS | Wholesale & retail | 2020 |
| CSB AS | Professional & scientific | 2023 |
| Cure Cosmetics AS | Wholesale & retail | 2023 |
| Cusso AS | Administrative & support | 2016 |
| Custom Bygg AS | Construction | 2026 |
| Cut'N Color AS | Other services | 2022 |
| Cut'N Go Haugesund AS | Other services | 2021 |
| Dagfinn Torstveit AS | Real estate | 2019 |
| Dagfinn Vee Holding AS | Health & social care | 2012 |
| Dahl Rammeservice AS | Manufacturing | 2008 |
| Dahlgren Eiendom AS | Real estate | 2025 |
| Dakar Bygg AS | Construction | 2024 |
| Dakki a AS | | 2018 |
| Dakki B AS | Real estate | 2018 |
| Dakki Drift AS | Real estate | 2016 |
| Dakki Verdi AS | Real estate | 2016 |
| Dalek AS | Information & communication | 2012 |
| Dalen Eiendom AS | Real estate | 1998 |
| Dallas Diving AS | | 2017 |
| Danica Foods AS | Manufacturing | 1993 |
| Daniel Karlsen Holding AS | Arts & recreation | 2020 |
| Danske'N AS | Hospitality | 2012 |
| Dari AS | Real estate | 2005 |
| DBB AS | Professional & scientific | 2022 |
| DC Nails and Beauty AS | Other services | 2022 |
| Dealmaker AS | Information & communication | 2011 |
| Deep Wind Offshore AS | Professional & scientific | 2020 |
| Deep Wind Offshore Employee Invest AS | Financial services | 2023 |
| Deep Wind Offshore Int AS | Professional & scientific | 2021 |
| Deep Wind Offshore Next AS | | 2023 |
| Deep Wind Offshore Norway AS | Professional & scientific | 2023 |
| Deep X AS | Professional & scientific | 2004 |
| Deepocean AS | Mining & quarrying | 1999 |
| Deepocean Maritime AS | Mining & quarrying | 1986 |
| Deepocean Shipping AS | Administrative & support | 1997 |
| Deepocean Shipping III AS | Transport & logistics | 1997 |
| Dekkstra Haugesund AS | Wholesale & retail | 2019 |
| Delantero Ltd Nuf | Financial services | 2005 |
| Demex AS | Wholesale & retail | 2018 |
| Den Norske Filmfestivalen AS | Arts & recreation | 1987 |
| Dental Eiendomsinvest AS | Real estate | 2025 |
| Depot Drift AS | Wholesale & retail | 1999 |
| Depotsjefen Da | Wholesale & retail | 2001 |
| Dermelie AS | Wholesale & retail | 2014 |
| Derro Invest AS | | 2009 |