| HN Bistro Oy | Hospitality | 2021 |
| HRM Consulting Oy | Education | 2011 |
| Hannes Johansson Capital Ab | Financial services | 2020 |
| Happy Horse Pro Oy | Arts & recreation | 2019 |
| Harrin Huvilahuolto ky | Construction | 1988 |
| Haslin Productions Ab | Information & communication | 2022 |
| Haval Khalil Oy | Other services | 2021 |
| Haven Import Ab | Real estate | 2023 |
| Havsglad Pargas Ab | Hospitality | 1994 |
| HeMa Invest Oy | Financial services | 2025 |
| HeatBeat Oy | Construction | 2022 |
| Hellberg Holding Ab | Financial services | 2015 |
| Henrik Laaksonen Management Oy | Professional & scientific | 2007 |
| HiDucator | Education | 2013 |
| Hoggais Östergård Ab Oy | Agriculture & fishing | 2014 |
| Holmfast Oy Ab | Real estate | 2011 |
| Holmo Viltfarm Kb | Agriculture & fishing | 1990 |
| Homevest Oy | Financial services | 2000 |
| Hotel Strandbo Oy | Hospitality | 1988 |
| Hovipellon Huolto Oy | Energy | 1979 |
| Hunger & Törst Ab | Hospitality | 2021 |
| Huoltoliike Kivinen Oy | Manufacturing | 2013 |
| Hydro-mek Oy Ab | Manufacturing | 2023 |
| Hydroteam Avoin yhtiö | Construction | 1990 |
| Hynni ja Pojat Oy | Professional & scientific | 2021 |
| Hyvinvointiklinikka Sentire Oy | Health & social care | 2012 |
| Hyvä Hytyrä Oy | Financial services | 2010 |
| IMM Palvelut Oy | Administrative & support | 2018 |
| Iloiset rakentajat Oy | Construction | 2021 |
| Impact Building Ab | Construction | 2021 |
| Improvida Oy | Manufacturing | 1990 |
| Ingenjörbyrå AC-Elplan Ab | Professional & scientific | 1993 |
| Innorange Oy | Information & communication | 2011 |
| Ins-Ma Oy Ltd | Manufacturing | 2006 |
| Insinööritoimisto - Ingenjörsbyrå Oy H. Ekblad Ab | Professional & scientific | 1988 |
| Insinööritoimisto John Engström Oy | Professional & scientific | 2023 |
| Insinööritoimisto Oy Para-Plan Ab Ingenjörsbyrå | Professional & scientific | 1978 |
| Insinööritoimisto Sven Sjöström Ab Oy | Professional & scientific | 2021 |
| Investorum Oy | Financial services | 2001 |
| Isaxxon Oy | Wholesale & retail | 2017 |
| Ison Talon Henkilöstöravintola & Keikkakeittiö Ky | Hospitality | 1991 |
| Isännöinti-Pauna Oy | Real estate | 2013 |
| J & A Eriksson Oy | Wholesale & retail | 2018 |
| J&M Ahtinen Oy | Wholesale & retail | 2019 |
| J-Rak Oy Ab Suunnittelu ja Rakennus | Professional & scientific | 2009 |
| JC-Import Oy | Real estate | 1996 |
| JFix Media Production Oy | Information & communication | 2025 |
| JHL Tech Oy Ab | Professional & scientific | 2025 |
| JN Fastinvest Oy Ab | Real estate | 2015 |
| JONAP Oy | Professional & scientific | 2019 |
| JRK Capital Oy | Construction | 2025 |
| JRTech Oy | Information & communication | 2015 |
| JS Merityö oy | Construction | 2018 |
| JaLe Konttivuokraus Oy | Real estate | 2023 |
| JaLe Line Oy | Transport & logistics | 2012 |
| Jalocraft Oy | Professional & scientific | 2026 |
| Jarma Oy | Real estate | 2024 |
| Jimmys butik Ab | Wholesale & retail | 2024 |
| Joakim Jansén Ab | Construction | 2016 |
| Jordkällaren AB | Other services | 2019 |
| Juristbyrå Lindholm Ab | Professional & scientific | 1995 |
| Just 4 Stars Oy Ab | Hospitality | 2023 |
| Jyppes Oy | Hospitality | 2020 |
| Jötte Invest Ab Oy | Real estate | 2004 |
| K&P Medica OY | Health & social care | 2025 |
| K-Support Oy Ab | Manufacturing | 2015 |
| KMS Hakala Oy | Professional & scientific | 2004 |
| Krisema-Leidit Osk | Wholesale & retail | 2014 |
| KV-Kiinteistöt Oy | Real estate | 2004 |
| Kaarinan sidonta ja Hautauspalvelu Oy | Wholesale & retail | 2009 |
| Kaarinan sähkötyö Oy | Construction | 1997 |
| Kaiku Terapiapalvelut Oy | Other services | 2026 |
| Kaino Vahalahden Liikenne Ky | Transport & logistics | 1989 |
| Kaius Hedenström Oy | Professional & scientific | 1982 |
| Kajupit Oy | Professional & scientific | 2021 |
| Kalkki Events Oy | Arts & recreation | 2025 |
| Kanerva Capital Oy | Professional & scientific | 2022 |
| KapuWorks Oy | Manufacturing | 2022 |
| Karjalan Tähti Oy | Other services | 2005 |
| Katayard Oy | Financial services | 2022 |
| Katsastus Mikkonen Oy | Professional & scientific | 2020 |
| Kauppahuone Berlin Ky | Wholesale & retail | 2023 |
| Kb Mega Collector Ky | Professional & scientific | 1991 |
| Kb R Levandoffsky Ky | Transport & logistics | 1988 |
| Kelovee Oy | Manufacturing | 1988 |
| Kermala Ravintolat Oy | Hospitality | 2014 |
| Kiinteistö Oy Annlof | Real estate | 2007 |
| Kiinteistö Oy Centralstranden Fastighets Ab | Real estate | 1981 |
| Kiinteistö Oy Himoskuovi | Real estate | 2014 |
| Kiinteistö Oy Juristinkallio | Real estate | 2010 |
| Kiinteistö Oy Kuusiston Konrad | Real estate | 1983 |
| Kiinteistö Oy Linnanaukko | Real estate | 2012 |
| Kiinteistö Oy Loma-Airisto II | Real estate | 1989 |
| Kiinteistö Oy Norrbyn teollisuustalo | Real estate | 2013 |
| Kiinteistö Oy Pankintalo | Real estate | 1990 |
| Kiinteistö Oy Paraisten Gunskogantie 28 | Real estate | 2019 |
| Kiinteistö Oy Paraisten Helmi | Real estate | 2004 |
| Kiinteistö Oy Paraisten Tammihaka | Real estate | 2004 |
| Kiinteistö Oy Paraisten Voimakatu 3 | Real estate | 1991 |
| Kiinteistö Oy Paraisten Vuoritie 4 | Real estate | 2000 |