| Akt Holding AS | Water & waste | 2016 |
| Akt Innvest AS | | 2026 |
| Akta Invest AS | Professional & scientific | 2022 |
| Aktiebolaget Brämhults Värmeteknik Nuf | Construction | 2023 |
| Aktieselskabet Kulspids | Real estate | 1910 |
| Aktieselskabet Maridalsveien 46 | Real estate | 1910 |
| Aktieselskapet Adamstuen Bygning 1 | Households | 1932 |
| Aktieselskapet Anton Schjøthsgt 13 | Households | 1916 |
| Aktieselskapet Bjerregaardsgate 24 | Real estate | 1919 |
| Aktieselskapet Frognerhuset | Households | 1924 |
| Aktieselskapet Gjende | Professional & scientific | 1991 |
| Aktieselskapet Gruegata 23 | Households | 1933 |
| Aktieselskapet Gyldenløvesgate 13 | Households | 1923 |
| Aktieselskapet Haakon Den Godes Vei 29 | Real estate | 1924 |
| Aktieselskapet Harbitzgate 20 | Real estate | 1910 |
| Aktieselskapet Neuberggaten 25 | Households | 1914 |
| Aktieselskapet Oaaa AS | Real estate | 2005 |
| Aktieselskapet Oslofjorden Eiendom | Real estate | 2002 |
| Aktieselskapet Pavels Gate 8 | Households | 1931 |
| Aktieselskapet Thomas Heftyesgate 60 | Households | 1915 |
| Aktieselskapet Ullevaal Stadion | Administrative & support | 1925 |
| Aktietrykkeriet Holding AS | | 2005 |
| Aktifys AS | Health & social care | 2002 |
| Aktimed Hauketo AS | Health & social care | 1988 |
| Aktion AS | Professional & scientific | 2020 |
| Aktiv Begeistring AS | Administrative & support | 2006 |
| Aktiv Bilservice Da | Other services | 1995 |
| Aktiv Boinvest AS | Real estate | 2007 |
| Aktiv Bolig AS | Real estate | 2013 |
| Aktiv Brannvern AS | Wholesale & retail | 1992 |
| Aktiv Bygg AS | Construction | 2000 |
| Aktiv Consulting AS | Professional & scientific | 2024 |
| Aktiv Containerutleie AS | Real estate | 2000 |
| Aktiv Eiendomsmegling AS | Real estate | 2001 |
| Aktiv Eiendomsoppgjør AS | Real estate | 2002 |
| Aktiv Form Da | Information & communication | 2002 |
| Aktiv Fritid Avlastning Da | Health & social care | 2010 |
| Aktiv Fysioterapi Romsås AS | Health & social care | 2014 |
| Aktiv I Oslo AS | Professional & scientific | 2012 |
| Aktiv Kompetanse AS | Real estate | 1998 |
| Aktiv Maler Entreprenør AS | Construction | 2025 |
| Aktiv Norgesdistribusjon AS | Transport & logistics | 2019 |
| Aktiv Og Ung AS | Arts & recreation | 1997 |
| Aktiv Portfolio AS | Real estate | 1988 |
| Aktiv Reklame Ans | Wholesale & retail | 1996 |
| Aktiv Reklame AS | Manufacturing | 2023 |
| Aktiv Reklame Holding AS | Manufacturing | 2007 |
| Aktiv Renhold Og Oppussing Da | Administrative & support | 2007 |
| Aktiv Service Utleie AS | Administrative & support | 2015 |
| Aktiv Tannklinikk AS | Health & social care | 2012 |
| Aktiv Terapi Kiropraktikk Og Idrettskonsulent AS | Health & social care | 2013 |
| Aktiv Trafikkskole AS | Education | 2011 |
| Aktiv Transport AS | Transport & logistics | 2016 |
| Aktiv Trening Romsås AS | Arts & recreation | 2019 |
| Aktiv Vaktmesterdrift AS | Administrative & support | 2022 |
| Aktiv Økonomi Ans | Professional & scientific | 1988 |
| Aktive-Renholdstjenester AS | Administrative & support | 2023 |
| Aktivia AS | Construction | 2025 |
| Aktivitet Norge AS | Administrative & support | 2019 |
| Aktivitetsbar AS | Hospitality | 2025 |
| Aktivt Eierskap AS | Professional & scientific | 2009 |
| Akto Eiendom AS | Real estate | 2018 |
| Akto Prosjekt AS | Professional & scientific | 2020 |
| Aktor AS | Administrative & support | 1985 |
| Aktuarverdi AS | Financial services | 2017 |
| Aktuell Bygg Service Ans | Construction | 1987 |
| Aktuelldata AB | Wholesale & retail | 1995 |
| Aku Invest AS | Financial services | 2011 |
| Akula AS | Wholesale & retail | 2004 |
| Akuleg AS | Health & social care | 1994 |
| Akurate AS | Professional & scientific | 2025 |
| Akustisk Bureau AS | Wholesale & retail | 2013 |
| Akustisk Puls AS | Arts & recreation | 2023 |
| Akutsu Holding AS | | 2026 |
| Akutt Diamantverktøy & Maskiner AS | Wholesale & retail | 2014 |
| Akutt Kiropraktikk Oslo AS | Health & social care | 2021 |
| Akutt Utleie AS | Administrative & support | 2001 |
| Akuttkompetanse AS | Education | 2023 |
| Akuttundervisning AS | Education | 2023 |
| Akv 7 AS | Real estate | 2023 |
| Akv AS | | 2026 |
| Akv Utvikling AS | Real estate | 2018 |
| Akva AS | | 2022 |
| Akvarieservice AS | Wholesale & retail | 2008 |
| Akvarium Mester AS | Wholesale & retail | 2023 |
| Akvasafe Invest AS | Agriculture & fishing | 2021 |
| Akvatech AS | Agriculture & fishing | 2011 |
| Akvatrust AS | Professional & scientific | 2022 |
| Akvedlikehold AS | Administrative & support | 2025 |
| Akvo Holding AS | | 2025 |
| Akz AS | Financial services | 2008 |
| Akzo Nobel Car Refinishes AB Nuf | Wholesale & retail | 2004 |
| Akzo Nobel Coatings AS | Wholesale & retail | 1987 |
| Al Basha AS | Wholesale & retail | 2024 |
| Al Basil Holding AS | Health & social care | 2021 |
| Al Bayt Hajj Services AS | Administrative & support | 2012 |
| Al Capital AS | | 2024 |
| Al Design AS | Professional & scientific | 2019 |
| Al Elektro AS | Construction | 2015 |
| Al Habib AS | Real estate | 1997 |