| Halo Tours Oy | Administrative & support | 2025 |
| HaloVault Oy | Financial services | 2026 |
| Haloan Oy | Financial services | 2011 |
| Halojaa Oy | Professional & scientific | 2019 |
| Halonen - Hallinto Oy | Financial services | 2003 |
| Halonen - Helsinki Oy | Wholesale & retail | 2019 |
| Halonen - Jyväskylä Oy | Wholesale & retail | 1995 |
| Halonen - Kokkola Oy | Wholesale & retail | 2002 |
| Halonen - Kotka Oy | Wholesale & retail | 1997 |
| Halonen - Kouvola Oy | Wholesale & retail | 2010 |
| Halonen - Lahti Oy | Wholesale & retail | 2011 |
| Halonen - Pori Oy | Wholesale & retail | 2000 |
| Halonen - Tampere Oy | Wholesale & retail | 1997 |
| Halonen - Vaasa Oy | Administrative & support | 2018 |
| Halonen Holding Oy | Financial services | 2019 |
| Halonen-Lappeenranta Oy | Wholesale & retail | 1997 |
| Halonen-Oulu Oy | Wholesale & retail | 2007 |
| Halonen-Seinäjoki Oy | Wholesale & retail | 1997 |
| Halonen-Turku Oy | Wholesale & retail | 1997 |
| Halong Bay Ky | Hospitality | 2025 |
| Haloo Agency Oy | Professional & scientific | 2020 |
| Haloo Music Group Oy | Arts & recreation | 2023 |
| Haloo Music Live Oy | Professional & scientific | 2023 |
| Halosen Himmeli Oy | Financial services | 2014 |
| Halosen verhoiluliike Oy | Other services | 2005 |
| Halsas LKV Oy | Real estate | 2016 |
| Halsing Oy | Professional & scientific | 2011 |
| Halstinho House Oy | Arts & recreation | 2021 |
| Halsuan Grid Oy | Energy | 2024 |
| Halsuan Tuulivoima Oy | Energy | 2014 |
| Haltaksi Oy | Transport & logistics | 2009 |
| Haltialan Tila Oy | Hospitality | 2026 |
| Haltian Toivot Oy | Health & social care | 2025 |
| Halttusen Sähkö Oy | Construction | 1970 |
| Halwick Oy | Professional & scientific | 2020 |
| Halycon Data Investment Oy | Financial services | 2026 |
| Halycon Wind Investment Oy | Financial services | 2026 |
| Ham Invest Oy | Professional & scientific | 2021 |
| Hamaca Invest Oy | Financial services | 2022 |
| Hamara Innovations Oy | Information & communication | 2012 |
| Hamata Oy | Wholesale & retail | 2014 |
| Hamburg Haus Oy | Hospitality | 2025 |
| Hamcon Oy | Professional & scientific | 2026 |
| Hamesmed Oy | Professional & scientific | 2022 |
| Hamico Oy | Real estate | 1994 |
| Hamide Oy | Hospitality | 1996 |
| Hamilton & Cooper Advisors Oy | Financial services | 2015 |
| Hamilton & Cooper Management Oy | Financial services | 2012 |
| Hamilton & Cooper Properties Oy | Real estate | 2012 |
| Hamina Terminal Oy | Transport & logistics | 2019 |
| Hamina Wireless Oy | Information & communication | 2021 |
| Haminan Tervasaari Oy | Real estate | 1989 |
| Haminan Tuulipuisto Oy | Energy | 2023 |
| Haminer Ky | Real estate | 1993 |
| Hamm Studios Oy | Arts & recreation | 2025 |
| Hammake Oy | Financial services | 2020 |
| Hammarsbågen Oy | Real estate | 2019 |
| Hammas-Apollo Oy | Health & social care | 1976 |
| Hammas-Arcus Oy | Health & social care | 2004 |
| Hammashoito Heikkilä Oy | Health & social care | 2014 |
| Hammashoito Komulainen Oy | Health & social care | 2019 |
| Hammashoito Timo Kaitemo Oy | Health & social care | 2000 |
| Hammashoitoasema OGADENT Oy | Health & social care | 2017 |
| Hammasilo Oy | Health & social care | 2025 |
| Hammaskeramiikkalaboratorio Matti Savolainen Oy | Health & social care | 1994 |
| Hammaskiille Oy | Health & social care | 1986 |
| Hammaslaboratorio Ceramic Oy | Manufacturing | 1997 |
| Hammaslaboratorio Estech Oy | Health & social care | 2002 |
| Hammaslaboratorio Hamtek Oy | Manufacturing | 2002 |
| Hammaslaboratorio Ilkka Tuominen Oy | Manufacturing | 2008 |
| Hammaslaboratorio Precident Oy | Manufacturing | 2002 |
| Hammaslaboratorio T-Hammas Oy | Manufacturing | 2010 |
| Hammaslaboratorio Takahammas Oy | Manufacturing | 1997 |
| Hammaslaboratorio Tilles Ky | Health & social care | 1986 |
| Hammaslaboratorio Wirodent Ky | Manufacturing | 1992 |
| Hammaslääkäri Emma Lakka Oy | Health & social care | 2022 |
| Hammaslääkäri Hyttinen Oy | Health & social care | 2026 |
| Hammaslääkäri J. Ranta Oy | Health & social care | 2023 |
| Hammaslääkäri R. Lindblad Oy | Health & social care | 2025 |
| Hammaslääkäri Tia Hakala Oy | Health & social care | 2024 |
| Hammaslääkäriasema Hammaskivi Oy | Health & social care | 1984 |
| Hammaslääkäriasema Hammaspeikko Oy | Health & social care | 2006 |
| Hammaslääkärikeskus Apollonia Oy | Health & social care | 1987 |
| Hammaslääkäripalvelu Heta Kokko Oy | Health & social care | 2023 |
| Hammaslääkäripalvelut Sami Rahman Oy | Health & social care | 2002 |
| Hammaslääkärit Helena Schildt ja Juha Sane | Health & social care | 1984 |
| Hammasmäki Oy | Health & social care | 2011 |
| Hammaspalvelu Jaakkonen Oy | Health & social care | 1992 |
| Hammaspalvelu Kalliomäki Oy | Health & social care | 2019 |
| Hammassalonki Oy | Health & social care | 1990 |
| Hammastarha Oy | Health & social care | 2014 |
| Hammastieto.fi Oy | Professional & scientific | 2020 |
| Hammasvelho Oy | Health & social care | 2012 |
| Hammer & Stones Oy | Construction | 2021 |
| HammerComm Oy | Hospitality | 2012 |
| Hammerax Oy | Construction | 2020 |
| Hammerfest Holding Oy | Financial services | 1998 |
| Hammtek Oy | Manufacturing | 2022 |
| Hampaasi Herttoniemi Oy | Health & social care | 2020 |
| Hamppusampo Oy | Wholesale & retail | 2018 |