| Aniv Invest AS | | 2026 |
| Anku Holding AS | Administrative & support | 2019 |
| Anlegg 24 AS | Construction | 2020 |
| Anlegg Og Graveservice AS | Construction | 2017 |
| Anleggservice Ålesund AS | Construction | 2015 |
| Annette Florvaag AS | | 2021 |
| Ans Adb Systems | | 1987 |
| Ans Borg Ålesund | Real estate | 1990 |
| Ans Gecco Import | Wholesale & retail | 1989 |
| Ans Gjerdegata 4 Ålesund | Real estate | 1990 |
| Ans Kristensens Eiendomsselskap | Real estate | 1986 |
| Ans Reidun Og Terje Skytterholm | Wholesale & retail | 1988 |
| Apex Academy AS | Education | 2023 |
| Apiri AS | Professional & scientific | 2017 |
| Aplysia Invest AS | | 2020 |
| Apoio Holding AS | Professional & scientific | 2016 |
| Apotekergaden 9 a + 9 B AS | Real estate | 2008 |
| Apotekergaden 9 a + B KS | Real estate | 2008 |
| Apotekergt 2 Ans | Real estate | 1989 |
| Appgres AS | Information & communication | 2019 |
| Application Consulting AS | Professional & scientific | 2025 |
| Apply IT AS | Information & communication | 1990 |
| Apricot Holding AS | | 2025 |
| Aqma AS | Professional & scientific | 2020 |
| Aqma Subsea AS | Professional & scientific | 2023 |
| Aqon AS | Agriculture & fishing | 2022 |
| Aqsolve AS | Professional & scientific | 2025 |
| Aqualytics AS | Manufacturing | 2025 |
| Aquarius Invest AS | Agriculture & fishing | 2005 |
| Aquatics AS | Professional & scientific | 2019 |
| Ar Service AS | Construction | 2012 |
| Arcaden Kiosk Og Video Da | Information & communication | 1994 |
| Arcadia AS | Professional & scientific | 1979 |
| Arcal Invest AS | Real estate | 2008 |
| Arctic Eagle AS | Agriculture & fishing | 2003 |
| Arctic Hydrogen AS | Manufacturing | 2022 |
| Arctic Innovative Solutions AS | Information & communication | 2016 |
| Arctos Consulting AS | Professional & scientific | 2019 |
| Are Steinsvåg AS | Construction | 2016 |
| Arealbygg 1 AS | Real estate | 2008 |
| Arella AS | | 2007 |
| Arenanorway AS | Arts & recreation | 2016 |
| Argma 790 Holding AS | | 2023 |
| Arguello AS | Real estate | 2019 |
| Aria Holding AS | | 2020 |
| Ariel SA | Real estate | 1955 |
| Arild Mork Instrumentering AS | Wholesale & retail | 1994 |
| Arild Rødal AS | Financial services | 2007 |
| Aritma Holding AS | | 2021 |
| Arkitekt John Stavseng AS | Professional & scientific | 1987 |
| Arkwiz AS | Information & communication | 2021 |
| Armis AS | Wholesale & retail | 2015 |
| Arne Lerstad AS | Real estate | 2014 |
| Art Arkitekter Og Ingeniører AS | Professional & scientific | 1985 |
| Artec Aqua Vaq AS | Wholesale & retail | 2002 |
| Artec Holding AS | | 2011 |
| Arteco AS | Administrative & support | 1989 |
| Artemis Angler AS | Professional & scientific | 2011 |
| Artemis Athene AS | Professional & scientific | 2012 |
| Artemis Shipping AS | Professional & scientific | 2007 |
| Artemis-Invest AS | | 2015 |
| Arthur Rønnestad Eftf. AS | Construction | 2002 |
| Artifex AS | Wholesale & retail | 2003 |
| Artifex Eiendom AS | Real estate | 2016 |
| AS Aalesundfisk | Wholesale & retail | 1974 |
| AS Aalesunds Margarinfabrik | Real estate | 1916 |
| AS Autogården | Real estate | 1938 |
| AS Byggetilfang | Professional & scientific | 1976 |
| AS Giskegt 28 | Households | 1916 |
| AS Havstrand | Agriculture & fishing | 1978 |
| AS Keiser Wilhelmsgate 25 | Real estate | 1964 |
| AS Kirkegaten 1 B | Real estate | 1953 |
| AS Nedre Strandgate 18 | Real estate | 1977 |
| AS Seaway Management | Transport & logistics | 1986 |
| Asander Holding AS | | 2026 |
| Asbjørn Berg & Co AS | Other services | 2022 |
| Asbjørnsen & Co AS. | Wholesale & retail | 2015 |
| Aservice AS | Administrative & support | 2011 |
| Asfaltservice AS | Construction | 1997 |
| Ask AS | Transport & logistics | 2012 |
| Ask Eiendommer AS | Real estate | 2013 |
| Ask Elearning AS | Information & communication | 2012 |
| Ask Safety AS | Education | 2014 |
| Ask Safety Holding AS | Education | 1995 |
| Askepott Barnehage AS | Education | 2022 |
| Askinvest AS | | 2021 |
| Askinvest Novus AS | | 2024 |
| Aspehaug AS | Information & communication | 2021 |
| Aspehaug Consulting AS | Professional & scientific | 2021 |
| Aspehaug Holding AS | Professional & scientific | 2013 |
| Aspevågen Marina AS | Manufacturing | 1988 |
| Aspøy AS | Transport & logistics | 1994 |
| Assist Ålesund AS | Wholesale & retail | 1998 |
| Assist Ålesund Holding AS | | 2025 |
| Assistit AS | Information & communication | 2023 |
| Asterix Bidco AS | Transport & logistics | 2017 |
| Asterix Holdco AS | Transport & logistics | 2017 |
| Asterix Topco 1 AS | Transport & logistics | 2018 |
| Asterix Topco 2 AS | Transport & logistics | 2018 |
| Astra Invest AS | Real estate | 1998 |