| Ans Majo | | 1989 |
| Apac Holding AS | Wholesale & retail | 2018 |
| Apex Tind AS | | 2026 |
| Apici AS | | 2025 |
| Appn AS | Information & communication | 2021 |
| Apptree Consulting AS | Information & communication | 2017 |
| Apptree Shop AS | Wholesale & retail | 2022 |
| Aqil AS | Wholesale & retail | 2022 |
| Ar Partner Bygg AS | Construction | 2013 |
| Arbeidsliv & Ergoterapi AS | Health & social care | 2018 |
| Arbeidslivskriminalitet Mot Bemanning Og Rekruttering Krzysztof Szkardkiewicz | Administrative & support | 2005 |
| Arc E-Commerce AB | Wholesale & retail | 2023 |
| Arco Eiendom AS | | 2014 |
| Arconsult Ove Bøe AS | Professional & scientific | 1986 |
| Arctic Asfalt AS | Construction | 2013 |
| Arctic Gruppen Holding AS | Construction | 2019 |
| Aritme Software AS | Information & communication | 2020 |
| Arkikad AS | Professional & scientific | 2023 |
| Arktek Holding AS | Construction | 2023 |
| Art for Centuries AS | Professional & scientific | 2017 |
| Arv AS | Hospitality | 2026 |
| Arv Express AS | Transport & logistics | 2021 |
| AS Handelsstedet Lilleborg | Real estate | 1928 |
| AS Viktoriaklinikken | Health & social care | 2018 |
| Asfalt Og Vei Consulting AS | Professional & scientific | 2023 |
| Asime Development AS | Real estate | 2003 |
| Asor Drift AS | Professional & scientific | 2022 |
| Asor Invest AS | Professional & scientific | 2021 |
| At Import AS | Wholesale & retail | 2019 |
| Atahk AS | Wholesale & retail | 2025 |
| Atil Holding AS | | 2025 |
| Atlp Holding AS | | 2025 |
| Auto Aura AS | Wholesale & retail | 2024 |
| Auto Care Jessheim AS | Other services | 2024 |
| Auto Salongen AS | Wholesale & retail | 2013 |
| Auto Sportslige Biler AS | Wholesale & retail | 2023 |
| Autocheckd AS | Information & communication | 2026 |
| Autofilm AS | Other services | 2018 |
| Automera AS | Wholesale & retail | 2025 |
| Automotive Consulting Group AS | Professional & scientific | 2015 |
| Autotrim AS | Wholesale & retail | 2024 |
| Autozentrum Jessheim AS | Wholesale & retail | 2013 |
| Avevia Medical AS | | 2026 |
| Avidus AS | | 2000 |
| Avokado Resorts AS | Transport & logistics | 2008 |
| Avp AS | Wholesale & retail | 2024 |
| Avvr AS | Administrative & support | 2025 |
| Akershus Traktor A/S | Wholesale & retail | 1988 |
| B&J Renhold Service Da | Administrative & support | 2018 |
| B. G. Renhold Nuf | Administrative & support | 2009 |
| Babya Jessheim AS | Wholesale & retail | 2023 |
| Bach-Gansmo AS | Transport & logistics | 2017 |
| Back in Time AS | Arts & recreation | 2014 |
| Backswing Invest AS | Education | 2018 |
| Baex Krüger Ans | Professional & scientific | 2001 |
| Bakken Invest AS | Financial services | 2005 |
| Bakkes Sidequests AS | Wholesale & retail | 2026 |
| Baklava House & Konditori AS | Hospitality | 2023 |
| Bape AS | Real estate | 2023 |
| Barbers of Norway AS | Other services | 2023 |
| Barish AS | Hospitality | 2011 |
| Barnehage- Og Vaktmester- Tjenester AS | Education | 2000 |
| Barntjernmoen Holding AS | Construction | 2020 |
| Bayco MC AS | Wholesale & retail | 2015 |
| BB Jessheim AS | Hospitality | 2022 |
| Bca Holding AS | Professional & scientific | 2025 |
| Be & M AS | Professional & scientific | 2006 |
| Be Airborne AS | Professional & scientific | 2016 |
| Be Bygg AS | Construction | 2026 |
| Bedriftsystemer AS | Wholesale & retail | 2016 |
| Beha Bygg AS | Construction | 2022 |
| Bekkedal Utvikling AS | Real estate | 2017 |
| Bekken Property AS | Real estate | 2025 |
| Beli Eiendom AS | Real estate | 2001 |
| Bent's Dekksenter Holding AS | | 2005 |
| Berg-Hansen Reisebureau Jessheim AS | Administrative & support | 1980 |
| Bergland Holding AS | | 2024 |
| Bertel O. Steen Jessheim AS | Other services | 2002 |
| Best Auto AS | Wholesale & retail | 2019 |
| Best Staffing AS | Administrative & support | 2025 |
| Bet IT AS | Information & communication | 2017 |
| Betaworks AS | Information & communication | 2024 |
| Betka AS | Construction | 2024 |
| Bevisste Valg AS | Professional & scientific | 2024 |
| Bie Sprinkler AS | Professional & scientific | 2020 |
| Billakkering Jessheim AS | Other services | 2022 |
| Billy Eiendom AS | Real estate | 1998 |
| Biltema Norge AS | Wholesale & retail | 2000 |
| Biltema Real Estate Norway AS | Real estate | 1976 |
| Biltema Sortland AS | Real estate | 2015 |
| Bimbygg AS | Professional & scientific | 2022 |
| Birdie Technologies AS | Information & communication | 2022 |
| Birdieeyes AS | Real estate | 2017 |
| Birkedal Holding AS | | 2022 |
| Birkenåsen Driftsselskap AS | Administrative & support | 2024 |
| Bisymi Invest AS | Real estate | 2008 |
| Bjelken Bygg AS | Construction | 2021 |
| Bjerktun Home AS | Real estate | 2025 |
| Bjervig Consulting AS | Professional & scientific | 2024 |
| Björkudden AS | Real estate | 2023 |