| Gundersens Holding AS | Real estate | 2021 |
| Gunnars Investeringer AS | Financial services | 2016 |
| Gustav S Eiendom AS | Real estate | 2015 |
| Gustavsen Invest AS | Financial services | 2013 |
| Gynekologen AS | Health & social care | 2012 |
| Gyro Inneklima Og Automasjon AS | Construction | 2024 |
| Gård & Fritid AS | Wholesale & retail | 2026 |
| H Og D Invest AS | Real estate | 2017 |
| H1 Communication AS | Administrative & support | 2017 |
| Haae Holding AS | | 2024 |
| Habo Leie Før Eie AS | Real estate | 2018 |
| Habo Niels Stubsgt. 1 AS | Real estate | 2021 |
| Haby AS | Real estate | 1996 |
| Haby Grønliveien 3 AS | Real estate | 2009 |
| Haby Norske Sjalusier AS | Manufacturing | 1995 |
| Haestr AS | Information & communication | 2020 |
| Hafsrød & Partners Eiendomsmegling AS | Real estate | 2007 |
| Halden Arbeid Og Vekst AS | Health & social care | 1965 |
| Halden Arbeid Og Vekst Holding AS | Health & social care | 2022 |
| Halden Arbeid Og Vekst Kommune AS | Health & social care | 2023 |
| Halden Arkitektkontor AS | Professional & scientific | 1996 |
| Halden Auto AS | Wholesale & retail | 1990 |
| Halden Autoservice AS | Other services | 2017 |
| Halden Betongtransport AS | Transport & logistics | 1987 |
| Halden Bilsenter AS | Wholesale & retail | 2015 |
| Halden Biochar Project AS | Manufacturing | 2023 |
| Halden Boligbyggelag Prosjekt AS | Real estate | 2000 |
| Halden Boligsenter AS | Real estate | 2006 |
| Halden Boligutvikling AS | Real estate | 2006 |
| Halden Brygge AS | Real estate | 2010 |
| Halden Bryggeri AS | Manufacturing | 2012 |
| Halden Bud Og Varetransport AS | Transport & logistics | 2005 |
| Halden Bygdeservice SA | Administrative & support | 2009 |
| Halden Bygg AS | Real estate | 1976 |
| Halden Byutvikling AS | Professional & scientific | 1999 |
| Halden Båt AS | Transport & logistics | 2011 |
| Halden Danselokale AS | Real estate | 2021 |
| Halden Dekk AS | Wholesale & retail | 1988 |
| Halden Dental AS | Manufacturing | 2010 |
| Halden Dental Da | Manufacturing | 1994 |
| Halden Drift AS | Wholesale & retail | 2006 |
| Halden Eiendom AS | Real estate | 1990 |
| Halden Eiendomsmegling AS | Real estate | 2026 |
| Halden Entreprenør AS | Construction | 2019 |
| Halden Farvehandel AS | Wholesale & retail | 2011 |
| Halden Flyttebyrå & Varexpress AS | Transport & logistics | 2003 |
| Halden Fysikalske Institutt Da | Health & social care | 2013 |
| Halden Fysioterapi- Og Kiropraktorklinikk Da | Health & social care | 2006 |
| Halden Gjenvinning AS | Wholesale & retail | 2014 |
| Halden Golf SA | Arts & recreation | 1990 |
| Halden Graving & Transport AS | Construction | 2023 |
| Halden Grunn Og Anlegg AS | Construction | 1996 |
| Halden Hud Og Laserklinikk AS | Other services | 2020 |
| Halden Håndverkstjenester AS | Construction | 2008 |
| Halden Invest AS | Real estate | 1968 |
| Halden Jeger- Og Villmarksklubb | Other services | 2013 |
| Halden Kjernekraft AS | Professional & scientific | 2023 |
| Halden Lastebilsentral AS | Transport & logistics | 1962 |
| Halden Lighthouse AS | Information & communication | 2021 |
| Halden Maskinservice AS | Wholesale & retail | 1995 |
| HALDEN MC OG OUTBOARD Leere & Pettersen DA | Wholesale & retail | 1989 |
| Halden Mikrobryggeri AS | Manufacturing | 2012 |
| Halden Montessoriskole AS | Education | 2012 |
| Halden Muskelterapeut AS | Education | 2024 |
| Halden Naprapatklinikk AS | Health & social care | 2013 |
| Halden Og Omegn Begravelsesbyrå AS | Other services | 1995 |
| Halden Padel AS | Arts & recreation | 2020 |
| Halden Palletransport AS | Transport & logistics | 2024 |
| Halden Papir, Henny Ann Eriksen, Kjell Eriksen Og Kjell Arne Eriksen Ans. | Manufacturing | 1986 |
| Halden Park Og Vaktmestertjenester AS | Administrative & support | 2016 |
| Halden Pizza AS | Hospitality | 2016 |
| Halden Prosjektutvikling AS | Real estate | 1986 |
| Halden Pubdrift Da | Hospitality | 1996 |
| Halden Rammemakeri AS | Manufacturing | 2023 |
| Halden Redning & Bilhjelp AS | Transport & logistics | 2024 |
| Halden Regnskap AS | Professional & scientific | 2018 |
| Halden Reklame Og Profilering AS | Professional & scientific | 2024 |
| Halden Renhold AS | Administrative & support | 2021 |
| Halden Revisjonsbyrå AS | Professional & scientific | 2008 |
| Halden Rørleggerservice AS | Construction | 2010 |
| Halden Sentrumsutvikling AS | | 2024 |
| Halden Servicestasjon AS | Wholesale & retail | 2011 |
| Halden Serviceutleie AS | Administrative & support | 2013 |
| Halden Skadesenter AS | Other services | 2021 |
| Halden Tannhelsesenter AS | Health & social care | 2017 |
| Halden Taxi AS | Transport & logistics | 1995 |
| Halden Taxibuss Ba | Transport & logistics | 1980 |
| Halden Torg AS | Real estate | 2010 |
| Halden Treningssenter AS | Arts & recreation | 2012 |
| Halden Ur Og Smykker AS | Wholesale & retail | 2004 |
| Halden Vaktmesterkompani AS | Administrative & support | 2014 |
| Halden Varmepumpeservice AS | Construction | 2025 |
| Halden VVS AS | Construction | 2026 |
| Halden Øre Nese Hals AS | Health & social care | 2025 |
| Haldencompagniet Da | Arts & recreation | 2020 |
| Haldentannlegene AS | Health & social care | 2016 |
| Hamilton-Gruppen AS | Real estate | 1965 |
| Han & Andersen Investment Company AS | | 2024 |
| Handymantjenesten AS | Construction | 2010 |
| Hanida Holdings AS | | 2025 |