| Grovehill real estate Oy | Real estate | 2024 |
| H & H Consulting Helsinki Oy | Professional & scientific | 2018 |
| H & H Consulting Oy | Professional & scientific | 2006 |
| H2N Invest Oy | Professional & scientific | 2024 |
| HK Capital Oy | Financial services | 2023 |
| HKK-Logistiikka Oy | Transport & logistics | 2018 |
| HP Kiropraktiikka Oy | Health & social care | 2023 |
| HR Sijoitus Oy | Financial services | 2018 |
| HT Architecture Oy | Professional & scientific | 2024 |
| HT RenoEstate Oy | Real estate | 2025 |
| Haka-Consulting Oy | Professional & scientific | 2003 |
| Hakki Group Oy | Arts & recreation | 2007 |
| HamKa Advisor Oy | Professional & scientific | 2024 |
| Hammas Kielo Oy | Health & social care | 2023 |
| Hammashelppi Oy | Information & communication | 2021 |
| Hammashuolto Sihvonen Oy | Health & social care | 2012 |
| Hammaslab Oy Kouvola | Manufacturing | 1989 |
| Hammaslääkäri Outi Rantanen Ky | Health & social care | 2007 |
| Hannu Aho Ky | Transport & logistics | 2004 |
| Happy Bowling Oy | Arts & recreation | 2018 |
| Happy Rouge Ventures Oy | Arts & recreation | 2019 |
| Happy brothers delivery Oy | Transport & logistics | 2022 |
| Haraltti Ky | Wholesale & retail | 2001 |
| Hasun Lihakauppa Ky | Wholesale & retail | 1985 |
| Hatech Kiinteistötekniikka Oy | Construction | 2013 |
| Hatei Sushi Oy | Hospitality | 2019 |
| Hautauspalvelu Lampila Oy | Other services | 1979 |
| Heidi Niemi LKV Oy | Real estate | 2023 |
| Heikari Oy | Professional & scientific | 2020 |
| Heimosen Kenkä - Becca Oy | Wholesale & retail | 1993 |
| Heinäkuu Oy | Wholesale & retail | 1990 |
| HeliPower Finland Oy | Professional & scientific | 2023 |
| Helm Invest Oy | Financial services | 2025 |
| Helmivalkea Oy | Health & social care | 2019 |
| Help Rent Henkilöstöratkaisut Oy | Administrative & support | 2023 |
| HelpU Oy | Health & social care | 2024 |
| Herger Oy | Professional & scientific | 2023 |
| Hessun Asennustyö Oy | Construction | 2020 |
| Hevi Yrityspalvelut Oy | Professional & scientific | 2022 |
| Hevi-Metalli Oy | Wholesale & retail | 1992 |
| Hevosmäki Oy | Agriculture & fishing | 1956 |
| Hiekkalahti Invest Oy | Financial services | 2025 |
| Hieronta Golden AuxiliuM Ky | Health & social care | 2015 |
| Hilpu avoin yhtiö | Wholesale & retail | 2015 |
| Hippikauppa Oy | Wholesale & retail | 2019 |
| Hirsiveistämö Karapuu Oy | Manufacturing | 2016 |
| Hitachi Rail Finland Oy | Construction | 2001 |
| Hitusen Oy | Health & social care | 2024 |
| Hiusboosti Oy | Other services | 2020 |
| Hiushuone inci Oy | Other services | 2024 |
| Hokkanen Franchise Oy | Wholesale & retail | 2008 |
| Hokkanen Möbel Oy | Administrative & support | 2008 |
| Holdz Oy | Other services | 2024 |
| Hopeapaja Olli Ronkka Oy | Manufacturing | 1981 |
| HoviRuoka Oy | Manufacturing | 2011 |
| Huoltamo M. Seppä Oy | Wholesale & retail | 1984 |
| Huoltopiste Sakki Oy | Other services | 1991 |
| Huomisen Metsä Oy | Real estate | 2012 |
| HuotariWorks Oy | Professional & scientific | 2020 |
| Huvipaja Oy | Arts & recreation | 1994 |
| Hyvinvointipalvelut Riikka Suomalainen Oy | Other services | 2016 |
| Hyvä Group Oy | Professional & scientific | 2016 |
| Hyvän mielen media Oy | Information & communication | 2018 |
| Ihan Mitä Vaan OY | Construction | 2025 |
| ISPIM Oy | Professional & scientific | 2021 |
| Ice Invest Capital Trading Oy Ltd | Financial services | 2026 |
| Igventure Oy | Professional & scientific | 2010 |
| Ikatrain Kiinteistö Oy | Real estate | 2001 |
| Ikatrain Museo Oy | Arts & recreation | 2001 |
| Ikkunasaneeraus P. Jäätvuori Oy | Professional & scientific | 1997 |
| Ilonan ihme Oy | Other services | 2019 |
| Ines-Consulting Oy | Professional & scientific | 2021 |
| Ines-Holding Oy | Financial services | 2021 |
| Infinity Jobs Oy | Administrative & support | 2025 |
| Infra Kymi Oy | Construction | 2017 |
| Inja Group Oy | Construction | 2024 |
| Inni Yhtiöt Oy | Other services | 2018 |
| Innomake Oy | Professional & scientific | 2017 |
| Insinor Oy | Professional & scientific | 2022 |
| Insinööritoimisto Alpo Koskivirta Oy | Professional & scientific | 1983 |
| Insinööritoimisto Hairo Ky | Professional & scientific | 2012 |
| Insinööritoimisto Hissitarkastuskeskus Ky | Manufacturing | 1989 |
| Insinööritoimisto JPM Oy | Professional & scientific | 2022 |
| Insinööritoimisto Paavo Parviainen Oy | Professional & scientific | 1993 |
| Insinööritoimisto Timo Vilèn, kommandiittiyhtiö | Construction | 1973 |
| Investing Habit Oy | Financial services | 2022 |
| IsaCon Laine Oy | Professional & scientific | 2017 |
| Iso Autohuolto Suomi Oy | Other services | 2007 |
| Israa palvelut OY | Transport & logistics | 2025 |
| Ita-Apu Oy | Professional & scientific | 2010 |
| J & E Piha- ja kivityöt Oy | Construction | 2000 |
| J & J Apu Oy | Construction | 2015 |
| J & R Pesu Avoin yhtiö | Construction | 1998 |
| J & S Kurvinen Ky | Hospitality | 2010 |
| J. Koskenniemi Oy | Education | 2024 |
| J. Mäkikunnas Invest Oy | Real estate | 2013 |
| J. Pöljö Maalarit Oy | Construction | 2000 |
| J. Sippu Ky - K-Asennuspalvelu | Construction | 1998 |
| J. Välimaa Ky | Construction | 2008 |
| JA-Pizza avoin yhtiö | Hospitality | 2019 |