| H-S Service & Vedlikehold AS | Administrative & support | 2025 |
| Haavaldsen Asfalt AS | Construction | 2022 |
| Haavaldsen Holding AS | Real estate | 2021 |
| Haganes AS | Real estate | 2016 |
| Hakein AS | Construction | 2012 |
| Hall Forvaltning AS | Real estate | 2007 |
| Hammer Agency AS | Wholesale & retail | 2026 |
| Hammeriet AS | Construction | 2023 |
| Hansen & Sønn Entreprenør AS | Professional & scientific | 2026 |
| Harper AS | Financial services | 2015 |
| Haukaas Rådgivning AS | Professional & scientific | 2022 |
| Headmaster AS | Other services | 2025 |
| Hedera Consulting AS | Professional & scientific | 2024 |
| Heia Vita AS | Health & social care | 2008 |
| Heia Vita Kommunale Tjenester AS | Health & social care | 2022 |
| Heiasvingen 37 AS | Wholesale & retail | 1991 |
| Heiasvingen 80 AS | Real estate | 2018 |
| Helse Og Utvikling AS | Health & social care | 2005 |
| Hendig AS | Administrative & support | 1990 |
| Hestnes AS | Wholesale & retail | 2014 |
| Historiske Fly AS | Administrative & support | 2022 |
| Hobbyco AS | Wholesale & retail | 2014 |
| Hobbykongen AS | Wholesale & retail | 2025 |
| Holdeko AS | | 2020 |
| Holding SYV8SEKS AS | Health & social care | 2024 |
| Homecheff AS | Hospitality | 2024 |
| Hope Elektro AS | Construction | 1997 |
| Hovedkvarter AS | Professional & scientific | 2020 |
| Hovin Holding AS | Financial services | 2008 |
| Hovinstrand AS | Real estate | 1967 |
| Hubroller AS | Wholesale & retail | 2025 |
| Høyden Holding AS | | 2025 |
| Ilkan AS | | 1990 |
| Impact Equity Holding AS | Information & communication | 2024 |
| Impact Insights AS | Professional & scientific | 2024 |
| Impact IT AS | Information & communication | 2024 |
| Impact Marketing AS | Professional & scientific | 2025 |
| Impera Holding Invest AS | Transport & logistics | 2022 |
| Indian Bygg AS | Construction | 1998 |
| Industriveien AS | Real estate | 1999 |
| Info-Eiendom AS | Real estate | 2022 |
| Info-Team AS | Real estate | 1990 |
| Innovam AS | Wholesale & retail | 2023 |
| Innregulerer Eriksson AS | Professional & scientific | 2017 |
| Insourcing Services AS | Professional & scientific | 2008 |
| Intx AS | Information & communication | 2010 |
| Isotex AS | Manufacturing | 2022 |
| Isvet AS | Professional & scientific | 2024 |
| IT Management & Consulting AS | Information & communication | 2018 |
| Ivyn AS | Wholesale & retail | 2016 |
| J-M Holding AS | Financial services | 2010 |
| Jacotron Marine AS | Wholesale & retail | 1998 |
| Jaksa Tømrer & Bad AS | Construction | 2021 |
| Jarn Eiendom AS | Real estate | 2019 |
| Jaws Holding AS | | 2021 |
| JMK Byggservice AS | Construction | 2022 |
| JTG Invest AS | | 2025 |
| Kadi Studio AS | Education | 2022 |
| Kald & Varm Installasjon AS | Construction | 2016 |
| Karma Foods AS | Hospitality | 2022 |
| Karte Holding AS | | 2022 |
| Kay Falla Transport AS | Transport & logistics | 1994 |
| KBL Holding AS | | 2021 |
| Kbrustad Holding AS | | 2025 |
| Kentaur AS | Wholesale & retail | 1999 |
| Ket-Os AS | Education | 2008 |
| KG Snekkeri AS | Construction | 2023 |
| Kikali AS | | 2021 |
| Kitchen Consulting AS | Professional & scientific | 2018 |
| KJ Elementdesign AS | Professional & scientific | 2012 |
| Kjell Volberg AS | Financial services | 2011 |
| Kjohnsen AS | | 2022 |
| Kjølberg Gruppen AS | Information & communication | 2021 |
| Kmk-Entreprenør AS | Construction | 2021 |
| Kob AS | Real estate | 2010 |
| Kolog AS | Professional & scientific | 2007 |
| Konglelia Holding AS | Financial services | 2015 |
| Konturer AS | Financial services | 2018 |
| Kraft Allianse AS | | 2016 |
| Krankonsulenten AS | Professional & scientific | 2024 |
| Krisanto AS | Transport & logistics | 2025 |
| Krohn Nettjenester AS | Information & communication | 2013 |
| Krown Fredrikstad AS | Transport & logistics | 2017 |
| Kursdama AS | Education | 2022 |
| Kvalitet Spesialisten AS | Other services | 2021 |
| L36 Invest AS | Financial services | 2009 |
| Larsens Takst Service AS | Real estate | 2013 |
| Lege MFK AS | Health & social care | 2025 |
| Leikvin Golfpark AS | Arts & recreation | 2001 |
| Lermo Transport AS | Transport & logistics | 2025 |
| LGK Tannklinikk AS | Health & social care | 2026 |
| Lie Veisten AS | Real estate | 2015 |
| Lillehagen Holding AS | | 2024 |
| Lillestrøm Boligventilasjon AS | Construction | 2022 |
| Lillestrøm Rør AS | Construction | 2020 |
| Lillestrøm Trafikkskole AS | Education | 2018 |
| Lindcon AS | | 2026 |
| Linealis AS | Professional & scientific | 2002 |
| Lire AS | Real estate | 2003 |
| Lm&T Clothing AS | Professional & scientific | 2021 |