| Arendal Viltlag SA | Agriculture & fishing | 2003 |
| Arendal Yogastudio AS | Education | 2016 |
| Arendal Øyelegesenter AS | Health & social care | 2019 |
| Arendals Bryggeri AS | Manufacturing | 2009 |
| Arendals Farvehandel AS | Wholesale & retail | 1988 |
| Arendals Fysikalske Institutt Ans | Real estate | 2005 |
| Arendalsadvokatene Da | Professional & scientific | 2020 |
| Arentsen AS | Professional & scientific | 1994 |
| Arius AS | Wholesale & retail | 2005 |
| Arnt Holding AS | Wholesale & retail | 2019 |
| Arnt Hår & Parykker AS | Other services | 2008 |
| Arnt J Mørland | Transport & logistics | 1919 |
| Arte Et Labore AS | Education | 2024 |
| Arto Eiendom AS | Real estate | 2001 |
| AS Assuransegården | Real estate | 1939 |
| AS Auto-Trade Service | Wholesale & retail | 1990 |
| AS Brekkegården | Real estate | 1983 |
| AS Eskulap | Real estate | 1969 |
| AS Havnegaten 3 | Real estate | 1982 |
| AS Planbygg | Construction | 1965 |
| AS Rapp | Real estate | 1995 |
| AS Univa | Wholesale & retail | 1984 |
| Asapco Invest AS | Real estate | 1982 |
| Asia.Com AS | Wholesale & retail | 2015 |
| Asian Market Arendal AS | Wholesale & retail | 2024 |
| Asktech AS | Information & communication | 2024 |
| Asne AS | Real estate | 2019 |
| Assev Bygg AS | Construction | 1997 |
| Astrid Saxi AS | Health & social care | 2026 |
| Atac Reklame AS | Professional & scientific | 2019 |
| Atel Alarm Og Telecom AS | Construction | 2002 |
| Ati Elektro AS | Construction | 2021 |
| Ati VVS AS | Construction | 2021 |
| Atletica - Idrettens Treningssenter AS | Arts & recreation | 2012 |
| Ausland & Bratlid AS | Professional & scientific | 2007 |
| Ausland Invest AS | Financial services | 2007 |
| Aust Agder Anleggsservice AS | Construction | 2015 |
| Aust-Agder Revisjon Rådgivning AS | Professional & scientific | 2020 |
| Aust-Agder Spedisjon AS | Transport & logistics | 1976 |
| Auto Company AS | Wholesale & retail | 2019 |
| Auto Trade Holding AS | Real estate | 2016 |
| Auto Zone AS | Wholesale & retail | 2023 |
| Autokraft AS | Wholesale & retail | 2001 |
| Autolakk Karosseri AS | Other services | 2022 |
| Autonom AS | Professional & scientific | 1990 |
| Autopower Norge AS | Wholesale & retail | 1996 |
| Autoservice Arendal AS | Other services | 2026 |
| Autostrada Arendal AS | Wholesale & retail | 1989 |
| Autostyring AS | Professional & scientific | 2021 |
| Avicon AS | Professional & scientific | 2024 |
| Avinet AS | Information & communication | 2025 |
| Assuranceforeningen Gard - gjensidig - | Financial services | 1907 |
| B&Z Bygg AS | Construction | 2023 |
| Baasland AS | Construction | 2004 |
| Baasland Eiendom AS | Real estate | 1982 |
| Bae Landskap AS | Professional & scientific | 2025 |
| Baker Jørgensen AS | Manufacturing | 2011 |
| Bakerovner.No AS | Wholesale & retail | 2022 |
| Ballistic Sportboats AS | Wholesale & retail | 2018 |
| Bambosa AS | Manufacturing | 2019 |
| Bane Sør AS | Administrative & support | 2011 |
| Bankgården Eiendom AS | Real estate | 2022 |
| Barbu Dybvands Bureau AS | Administrative & support | 2019 |
| Barbu Næringssenter AS | Real estate | 2007 |
| Barbu Telehus AS | Real estate | 2022 |
| Bare Pluss AS | Real estate | 2021 |
| Bareb AS | Professional & scientific | 2019 |
| Barebcoms AS | Professional & scientific | 2021 |
| Barnas Klippotek AS | Other services | 2017 |
| Barnelege Oliver Scheck AS | Health & social care | 2024 |
| Barrikk AS | Hospitality | 2020 |
| Batteri Elektro AS | Other services | 2014 |
| Batteri Elektro Eiendom AS | Real estate | 2010 |
| Batteri Elektro Holding AS | Other services | 2014 |
| BBC Eiendom AS | Real estate | 2004 |
| Bea Eiendom AS | Real estate | 1990 |
| Beauty Bar Arendal AS | Other services | 2024 |
| Beauty Studio Camilla AS | Other services | 2020 |
| Bedriftsveien 17 AS | Real estate | 2007 |
| Bedriftsveien 22 Arendal AS | Real estate | 2014 |
| Bedriftsveien 24 Arendal AS | Real estate | 2020 |
| Beinset Energy AS | Professional & scientific | 2012 |
| Bella Italia AS | Wholesale & retail | 2024 |
| Belland Consult AS | Professional & scientific | 2022 |
| Bemar Invest AS | | 2026 |
| Berge-Westgaard AS | | 2021 |
| Bergotter Eiendom AS | Real estate | 1998 |
| Beslagfabrikken AS | Manufacturing | 2011 |
| Bevar AS | Real estate | 2025 |
| BF Auto Helle & Pedersen Ans | Other services | 1994 |
| BG Trading AS | Wholesale & retail | 2012 |
| Biestø Båt Badstue AS | Administrative & support | 2025 |
| Biestø Båthavn AS | Real estate | 2012 |
| Bil for Deg AS | Wholesale & retail | 2023 |
| Bilagent AS | Wholesale & retail | 2024 |
| Bilbutikken Arendal AS | Wholesale & retail | 2010 |
| Bilredning Sør AS | Transport & logistics | 2006 |
| Bilreparatørene AS | Other services | 2008 |
| Bilutstyr Arendal AS | Wholesale & retail | 1991 |
| Bilvask.No Myrene AS | Other services | 2018 |