| Hammaslaboratorio Ari Ahrikkala Ky | Manufacturing | 1990 |
| Hammaslääkäri Johanna Jauhola Oy | Health & social care | 2025 |
| Hanhirova Family Holding Oy | Financial services | 2007 |
| Hannukainen Mining Oy | Mining & quarrying | 2014 |
| Hannulanmäen Jäähalli Oy | Arts & recreation | 1999 |
| Harlabs Oy | Manufacturing | 2024 |
| Harri Mikkola Ky | Wholesale & retail | 1997 |
| Hartop Asennuspalvelu Oy | Manufacturing | 2021 |
| Hast Kiinteistöt Oy | Real estate | 1998 |
| Havutech Oy | Manufacturing | 2008 |
| Heavystone Oy | Mining & quarrying | 2019 |
| HeiPek Oy | Wholesale & retail | 2023 |
| Heimo Rautio Oy | Other services | 1990 |
| Helaus Oy | Real estate | 1995 |
| Heleiina Oy | Manufacturing | 2025 |
| Hello Asian Store Oy | Wholesale & retail | 2025 |
| Henkilöpalvelu TKJ Oy | Professional & scientific | 2020 |
| Henry Sunnari Oy | Manufacturing | 2024 |
| Herajärven Kuljetus Oy | Transport & logistics | 1982 |
| Heriq Capital Oy | Financial services | 2026 |
| HerkkuPeikko Oy | Hospitality | 2008 |
| Hesand Oy | Professional & scientific | 2009 |
| Hicut Oy | Manufacturing | 2014 |
| Hinaus Teppola Oy | Transport & logistics | 2021 |
| Hirvas Levi Oy | Real estate | 2000 |
| HoPa Asunnot Oy | Health & social care | 2012 |
| Hoitokeino Naasko Oy | Health & social care | 2026 |
| Holmantien Pizzeria & Pub Oy | Hospitality | 2021 |
| Holmberg Cases Oy | Wholesale & retail | 1989 |
| Hookanan Turkistarha Ky | | 1986 |
| Hopea Palvelut Oy | Health & social care | 2008 |
| Hotelli Kaamos Ky | | 1992 |
| Hovi Steel Oy | Manufacturing | 2021 |
| Hovilompolo avoin yhtiö | Hospitality | 2000 |
| Hulado Oy | Financial services | 2020 |
| Huoli Bois Oy | Financial services | 2019 |
| Huoltamo Jouko Kihlanki Ky | Wholesale & retail | 1989 |
| HuoltoTek Oy | Other services | 2026 |
| Husex Oy | Professional & scientific | 2018 |
| Hyvinvointi Virtaava Oy | Health & social care | 2023 |
| Hyvinvointikeskus Koppi Oy | Health & social care | 2023 |
| IHD Works Oy | Manufacturing | 2022 |
| IKA-Rakennus Ky | Construction | 2005 |
| ISRI Kiinteistöt Oy | Real estate | 2019 |
| IVMontage Oy | Manufacturing | 2024 |
| IikCapital Oy | Agriculture & fishing | 2021 |
| Iisikari Oy | Real estate | 2024 |
| Ilmolan Talopalvelu Ky | Real estate | 1983 |
| In Car Import Ky | Wholesale & retail | 2016 |
| Inatec Oy | Professional & scientific | 2018 |
| Industrial Partners Group Oy | Professional & scientific | 2023 |
| Innala Tours Oy | Administrative & support | 2021 |
| Insafety Oy | Administrative & support | 2023 |
| Insinööritoimisto 3D Hacklin Oy | Professional & scientific | 2011 |
| Insinööritoimisto Bothnia Raktek Oy | Construction | 1995 |
| Insinööritoimisto EOTEC Oy | Professional & scientific | 2025 |
| Insinööritoimisto REITEK Oy | Professional & scientific | 2005 |
| Insinööritoimisto Rak-Tor OY | Professional & scientific | 2007 |
| Insinööritoimisto Timo Pöykkölä Oy | Professional & scientific | 2014 |
| Invest in West Oy | Construction | 2023 |
| Isojänkä Oy | Real estate | 2002 |
| Isomet Oy | Manufacturing | 2022 |
| Isto-Invest Oy | Financial services | 1987 |
| Isännöinti- ja Tilitoimisto A. Kivekäs Ky | Real estate | 1984 |
| Itärannan Kiinteistökehitys Oy | Real estate | 2022 |
| J & T Hamari Oy | Other services | 2019 |
| J Paakkolanvaara Ky | Wholesale & retail | 1990 |
| J&J Hirsikangas Oy | Other services | 2021 |
| J&J Lakkapää Oy | Administrative & support | 1986 |
| J. Arpi Oy | Agriculture & fishing | 2022 |
| J.E. Service Ky | Other services | 2011 |
| J.F.Tornio OY | Wholesale & retail | 2014 |
| J.Konstenius Oy | Agriculture & fishing | 2004 |
| J.M. Coolfoods Oy | Wholesale & retail | 2015 |
| J.Pyyny Investments Oy | Real estate | 2022 |
| JAPY Oy | Wholesale & retail | 2019 |
| JH-Lastaus Oy | Construction | 1995 |
| JH-Pipe Ky | Construction | 2011 |
| JHM Elämys Oy | Arts & recreation | 2022 |
| JHO-Tuote Oy | Wholesale & retail | 2021 |
| JJ-Proffs Oy | Professional & scientific | 2022 |
| JKV-Yhtiöt Oy | Financial services | 2015 |
| JL Rakennus ja sisustus Ky | Construction | 2018 |
| JL-Tools Oy | Manufacturing | 2016 |
| JM Quality Oy | Financial services | 2020 |
| JMA-Yhtiöt Oy | Construction | 2012 |
| JME Palvelut Oy | Transport & logistics | 2022 |
| JMJ House Oy | Real estate | 2019 |
| JMV-Rakennus Oy | Construction | 2012 |
| JP-LIFT Oy | Construction | 1992 |
| JPK Autopalvelut Oy Ab | Other services | 2024 |
| JPT Group Oy | Professional & scientific | 2021 |
| JS Piping Oy | Manufacturing | 2010 |
| JS-Sähköpalvelu Oy | Construction | 2014 |
| JSB Palvelu Oy | Wholesale & retail | 2006 |
| JSL Autohuolto Oy | Other services | 2007 |
| JT Autopikahuolto Oy | Other services | 2022 |
| JTP-Trans Ky | Transport & logistics | 1994 |
| Jumatek OY | Administrative & support | 2011 |
| JVP-Urakointi Oy | Construction | 2014 |