| Akaasia Oy | Financial services | 1993 |
| Akalchaili oy | Professional & scientific | 2010 |
| Akalipa Oy | Financial services | 2025 |
| Akanatek Ky | Information & communication | 2018 |
| Akasia Palvelut Oy | Hospitality | 2025 |
| Akateeminen Kirjakauppa Oy | Wholesale & retail | 2015 |
| Akateeminen Kustannusliike Oy | Information & communication | 1959 |
| Akateeminen ennuste Oy - Akademisk prognos Ab | Professional & scientific | 2026 |
| Akdora Oy | Hospitality | 2012 |
| Akentech Oy | Information & communication | 2023 |
| Aket Oy | Professional & scientific | 2021 |
| Akhanda oy | Hospitality | 2023 |
| Aki Björklund oy ab | Information & communication | 2018 |
| Aki Heinonen Consulting Oy | Information & communication | 2014 |
| Aki Lahtinen Oy | Administrative & support | 2008 |
| Aki Pursiainen Oy | Professional & scientific | 2020 |
| Aki Rosén Oy | Administrative & support | 2023 |
| AkiMatiC Oy | Other services | 2024 |
| Akiha Oy | Professional & scientific | 2018 |
| Akil Automotive Oy | Wholesale & retail | 2024 |
| Akin Kyyti Oy | Transport & logistics | 2007 |
| Akin Sähkö Oy | Construction | 2003 |
| Akin Yhtiöt Oy | Professional & scientific | 2021 |
| Akino Oy | Hospitality | 2023 |
| Akion Oy | Wholesale & retail | 2017 |
| Akira puppy love Oy | Information & communication | 2022 |
| Akitre Oy | Financial services | 2021 |
| Akiva GP I Oy | Financial services | 2018 |
| Akiva Kiinteistöt I Feeder Ky | Real estate | 2022 |
| Akiva Oy | Financial services | 2017 |
| Akkeber Events Oy | Education | 2022 |
| Akkelimo Oy | Construction | 2022 |
| Akkep Oy | Professional & scientific | 1990 |
| Akklek Oy | Manufacturing | 2025 |
| Akku Capital Oy | Financial services | 2019 |
| Akku-Palvelu V. Häkkinen Oy | Wholesale & retail | 1979 |
| Akkukellari Oy/Ab | Wholesale & retail | 2007 |
| Akkukierrätys Pb Oy | Water & waste | 2008 |
| Akkunavarasto Oy | Construction | 1923 |
| Akkus & Karagöl Oy | Hospitality | 1999 |
| Akkutehdas Helsinki Oy | Manufacturing | 2018 |
| Akkutehdas Vuosaari Oy | Manufacturing | 2026 |
| Akkutien pesula Oy | Other services | 2023 |
| Akmakor Oy | Professional & scientific | 2022 |
| Akmal Holding Oy | Financial services | 2026 |
| Akmalito Ab | Professional & scientific | 2025 |
| Akniron Invest Oy | Financial services | 2024 |
| Akon Holdings Ltd Oy | Real estate | 2023 |
| Akona Oy | Professional & scientific | 2023 |
| Akordi Oy | Professional & scientific | 2013 |
| Akra-Numero Oy | Professional & scientific | 2016 |
| Akram Group Oy | Wholesale & retail | 2023 |
| Akrazzo Oy | Professional & scientific | 2025 |
| Akreative Consulting Oy | Professional & scientific | 2024 |
| Akrieer Oy | Professional & scientific | 1993 |
| Akritas Advisory Oy | Professional & scientific | 2018 |
| Akron Consulting Oy | Professional & scientific | 1995 |
| Akropolin Herkku Oy | Hospitality | 2013 |
| Akropolis Greek Grill Oy | Hospitality | 2020 |
| Akroz Oy | Financial services | 2003 |
| Akrén Oy | Health & social care | 2026 |
| Aksa Palvelut Oy | Construction | 2024 |
| Aksako Oy | Professional & scientific | 2019 |
| Aksavo Finance Oy | Financial services | 1989 |
| Aksel & Son Oy | Professional & scientific | 1992 |
| Aksel Närvänen & Co | Transport & logistics | 1962 |
| Akseli-Huolto Service Ky Knut Lindfors | Other services | 1989 |
| Akses Oy | Professional & scientific | 2018 |
| Akshar Food Oy | Hospitality | 2025 |
| Aksidenssi Oy | Manufacturing | 1989 |
| Aksion solutions Oy | Administrative & support | 2021 |
| Aktavit Oy | Financial services | 1988 |
| Aktek Oy | Construction | 2022 |
| Aktia Alexander Corporate Finance Oy | Financial services | 2005 |
| Aktia Asuntorahasto VIII Ky | Financial services | 2021 |
| Aktia Asuntorahasto VIII Omistajat Ky | Financial services | 2021 |
| Aktia Asuntorahasto VIII Rahoittajat Ky | Financial services | 2021 |
| Aktia Asuntorahasto VIII Sijoittajat 100 Ky | Financial services | 2021 |
| Aktia Asuntorahasto VIII Sijoittajat 500 Ky | Financial services | 2021 |
| Aktia Asuntorahasto Vlll GP Oy | Financial services | 2021 |
| Aktia Aurinkotuuli III GP Oy | Financial services | 2023 |
| Aktia Aurinkotuuli III Henkilökunta Ky | Financial services | 2023 |
| Aktia Aurinkotuuli III Ky | Financial services | 2023 |
| Aktia Aurinkotuuli III Omistajat Ky | Financial services | 2023 |
| Aktia Aurinkotuuli III Rahoittajat Ky | Financial services | 2023 |
| Aktia Aurinkotuuli III Sijoittajat 100 Ky | Financial services | 2023 |
| Aktia Aurinkotuuli III Sijoittajat 500 Ky | Financial services | 2023 |
| Aktia Bank Abp | Financial services | 2008 |
| Aktia Bioteollisuus I GP Oy | Financial services | 2021 |
| Aktia Bioteollisuus I Ky | Financial services | 2022 |
| Aktia Bioteollisuus I Omistajat Ky | Financial services | 2022 |
| Aktia Bioteollisuus I Rahoittajat Ky | Financial services | 2022 |
| Aktia Bioteollisuus I Sijoittajat 100 Ky | Financial services | 2022 |
| Aktia Bioteollisuus I Sijoittajat 500 Ky | Financial services | 2022 |
| Aktia Fondbolag Ab | Financial services | 2006 |
| Aktia Housing GP Oy | Financial services | 2020 |
| Aktia Housing Ky | Financial services | 2020 |
| Aktia Kiinteistönvälitys Oy | Real estate | 1994 |
| Aktia Private Equity I GP Oy | Financial services | 2022 |
| Aktia Velkarahastot II GP Oy | Financial services | 2022 |