| HRT Asunnot Oy | Real estate | 2017 |
| HW Sijoittajat Oy | Administrative & support | 2022 |
| HWT Yhtiöt OY | Manufacturing | 2020 |
| Haavisto-Kiinteistöt Oy | Real estate | 2020 |
| Hahko Farm Oy | Agriculture & fishing | 2023 |
| Hahko Oy | Construction | 2016 |
| Hannest oy | Administrative & support | 2018 |
| Haretek Oy | Manufacturing | 1994 |
| Harmaatalo Oy | Real estate | 1995 |
| Hautaustoimisto ja Kukkasitomo P. Kaunisto Ky | Other services | 1990 |
| Hautomo Veka Oy | Agriculture & fishing | 1989 |
| Heavy Trailers Oy Huittinen | Manufacturing | 2026 |
| HeavyCargo Team Oy | Transport & logistics | 2015 |
| Heikki Ahonen Ky | Manufacturing | 1986 |
| Heison Oy | Wholesale & retail | 2024 |
| Henkilöstöpalvelu Laine Oy | Administrative & support | 2018 |
| Hennu Oy | Agriculture & fishing | 2016 |
| HiMa Catering Oy | Hospitality | 2016 |
| Himosmajat Oy | Hospitality | 2006 |
| Hinauspalvelu Ojala Oy | Transport & logistics | 2011 |
| Hintahammas Oy | Hospitality | 1993 |
| HoldCo Oy Sastamalan Trakinkatu 10 | Real estate | 2016 |
| Hufo Oy | Wholesale & retail | 1991 |
| Huikkaus Oy | Hospitality | 2015 |
| Huittisten Ajo-Auto Oy | Wholesale & retail | 1994 |
| Huittisten Ajoneuvohuollon Auto Oy | Other services | 1999 |
| Huittisten Ammattiasennus Oy | Real estate | 2020 |
| Huittisten Autopiste Ky T. Mäkelä | Wholesale & retail | 1989 |
| Huittisten Autotalo Oy | Real estate | 1994 |
| Huittisten Bag Team Oy | Real estate | 1994 |
| Huittisten Fysioterapia Oy | Health & social care | 2012 |
| Huittisten Herkkuburger Oy | Hospitality | 1973 |
| Huittisten Horse Center Oy | Wholesale & retail | 1993 |
| Huittisten Härkäburger Oy | Hospitality | 2002 |
| Huittisten JP-Rakennuspelti Oy | Construction | 2005 |
| Huittisten Jäähalli Oy | Arts & recreation | 1996 |
| Huittisten Kaupunkiasunnot Oy | Real estate | 1990 |
| Huittisten Kirjakauppa Oy | Wholesale & retail | 2014 |
| Huittisten Kone ja Sammutin Oy | Construction | 1997 |
| Huittisten Koti-ikkuna Oy | Real estate | 2008 |
| Huittisten Kuljetus Oy | Transport & logistics | 1989 |
| Huittisten Kylmävarasto Oy | Transport & logistics | 2006 |
| Huittisten Käyttörengas Oy | Wholesale & retail | 2006 |
| Huittisten Lasipaja Oy | Construction | 2004 |
| Huittisten Lääkäripalvelu Oy | Health & social care | 1987 |
| Huittisten P.T. Rakennus Oy | Construction | 2004 |
| Huittisten Praktiikka Oy | Health & social care | 2000 |
| Huittisten Puhdistamo Oy | Water & waste | 2012 |
| Huittisten Ryhmärakentajat Oy | Construction | 1993 |
| Huittisten Sanomalehti Oy | Information & communication | 1915 |
| Huittisten Siirtokuljetus Oy | Transport & logistics | 2004 |
| Huittisten Silkkipaino, avoin yhtiö | Manufacturing | 1989 |
| Huittisten Specialmotors Oy | Other services | 2006 |
| Huittisten Sähkötekniikka Oy | Wholesale & retail | 1995 |
| Huittisten Säästömarket Oy | Wholesale & retail | 1991 |
| Huittisten Taksipalvelu Antti Huhtala Oy | Transport & logistics | 2025 |
| Huittisten Talohuolto Oy | Administrative & support | 2005 |
| Huittisten Tapetti ja Väri Oy | Wholesale & retail | 1989 |
| Huittisten Tilataksi Oy | Transport & logistics | 2018 |
| Huittisten Tilausliikenne Oy | Transport & logistics | 2005 |
| Huittisten Toivehallit Oy | Real estate | 1986 |
| Huittisten Ula-Taksi Oy | Information & communication | 1985 |
| Huittisten Urheilutarvike Oy | Wholesale & retail | 1998 |
| Huittisten Vartioimisliike Ky | Administrative & support | 1992 |
| Huittisten huolto- ja apumiespalvelu Ky | Other services | 2017 |
| Huittisten keila- ja pelihalli Oy | Arts & recreation | 2013 |
| Huittisten kotilääkäri Oy | Health & social care | 2018 |
| Huittisten optiikka oy | Wholesale & retail | 2022 |
| Huolto ja Varaosa Oy | Wholesale & retail | 1955 |
| Hupa Invest Oy | Arts & recreation | 2026 |
| Härkäpakari Oy | Hospitality | 1990 |
| ITORA-Invest Oy | Transport & logistics | 2008 |
| Idoneum Clothes Oy | Wholesale & retail | 2017 |
| Inkisen Kotiteollisuus avoin yhtiö | Construction | 1995 |
| IsiTa Ky | Other services | 1984 |
| Isännöintitalo Virtanen Oy | Real estate | 2014 |
| Itora-Kiinteistöt Oy | Real estate | 2012 |
| J & J Suoja Oy | Wholesale & retail | 2007 |
| J & M Haavisto Oy | Transport & logistics | 1997 |
| JEM-Kiinteistöt Oy | Real estate | 2004 |
| JH Pesuhuollot OY | Other services | 2011 |
| Jii-Vee Apu OY | Manufacturing | 2025 |
| JK Proof Oy | Construction | 2015 |
| JK-Brossi Oy | Manufacturing | 1996 |
| JLG Yacht Interior Assembly Oy | Manufacturing | 2024 |
| JME-Autohuolto Oy | Other services | 2021 |
| JMT Group Oy | Administrative & support | 2024 |
| JR Jalot Oy | Wholesale & retail | 2018 |
| JTM-Voitelutukku Oy | Transport & logistics | 2021 |
| JVH-Palvelut Ky | Wholesale & retail | 2011 |
| JVK Vehicles Oy | Wholesale & retail | 2019 |
| JVP Group M. Koskinen Oy | Real estate | 2025 |
| Jarmed Oy | Health & social care | 2018 |
| Jarmo Ketola Ky | Transport & logistics | 2006 |
| Jarmo Sivunen Ky | Wholesale & retail | 1987 |
| Jokanra Oy | Administrative & support | 1993 |
| Jokisen Jouni Oy | Administrative & support | 2024 |
| Jokisivun Dynamo Oy | Administrative & support | 2020 |
| Joletek Oy | Manufacturing | 1985 |
| Joletek Works Oy | Manufacturing | 2025 |