| Oy Inmera Ab | Professional & scientific | 1987 |
| Oy Insinööritoimisto Recon Ingenjörsbyrå Ab | Professional & scientific | 2017 |
| Oy Insno Ab | Construction | 1991 |
| Oy Intercarriers Ltd | Transport & logistics | 1992 |
| Oy Intercentra Ab | Wholesale & retail | 1978 |
| Oy Isänn.toim. Nyholm Disp.byrå Ab | Real estate | 1989 |
| Oy Ivnäs Ab | Real estate | 1990 |
| Oy JM Sportsbar Ab | Hospitality | 1989 |
| Oy JaHa Ernst Ab | Hospitality | 2012 |
| Oy Jobinvest Ltd | Professional & scientific | 2012 |
| Oy Jukimar | Financial services | 1997 |
| Oy Jörgen & Kaj Ab | Manufacturing | 2014 |
| Oy K. Lytz Ab | Wholesale & retail | 1992 |
| Oy KA Support Ab | Professional & scientific | 2023 |
| Oy KIHA-Team Ab | Real estate | 2024 |
| Oy KIHA-Team Kokkola-Pietarsaari | Real estate | 2025 |
| Oy KIHA-Team Vaasa - KIHA-Team Vasa Ab | Real estate | 2022 |
| Oy KJL-Yhtiö Ab | Wholesale & retail | 1990 |
| Oy KPT Marketing Ab | Professional & scientific | 2000 |
| Oy Kanki Verstas Ab | Arts & recreation | 2025 |
| Oy Kardan Ab | Other services | 1945 |
| Oy Kim Somppi Ab | Professional & scientific | 2019 |
| Oy Kolmatic Ab | Manufacturing | 1988 |
| Oy Komofon Ab | Other services | 1988 |
| Oy Kone Nygård Maskin Ab | Wholesale & retail | 1961 |
| Oy Kontaktor Ab | Construction | 1949 |
| Oy Korsholman Pokasaha Ab | Real estate | 1973 |
| Oy Kron Plastic Ab | Real estate | 1970 |
| Oy Kråklund Golf Ab | Arts & recreation | 1989 |
| Oy Kuljetusliike K Meriläinen Ab | Transport & logistics | 2014 |
| Oy Kumi-Järvinen Ab | Wholesale & retail | 1986 |
| Oy Kuormaus ja Kuljetus Berg Last och Transport Ab | Transport & logistics | 1989 |
| Oy Kurre Erä ja Kalastus - Jakt och Fiske Ab | Wholesale & retail | 1981 |
| Oy Kuurila-Svahn Ab | Health & social care | 2016 |
| Oy Käkilämpö Ab | Energy | 1965 |
| Oy Källarmästarens Ab | Hospitality | 1993 |
| Oy Lakiasiat Jukka Vainio Ab | Professional & scientific | 2018 |
| Oy Lamreon Ltd | Professional & scientific | 2025 |
| Oy Leinolat Ab | Manufacturing | 1976 |
| Oy Leinolat Corporation Ab | Manufacturing | 2026 |
| Oy Levysepänliike Sundqvist - Plåtslageri Sundqvist Ab | Construction | 1988 |
| Oy Liikennekoulu Rönn Trafikskola Ab | Education | 1991 |
| Oy Lindgård Invest Ab | Professional & scientific | 2003 |
| Oy Lito-Botnia Ab | Manufacturing | 2004 |
| Oy Logiprime Ab | Professional & scientific | 2020 |
| Oy Lomavecon Ab | Real estate | 1990 |
| Oy LämpöHomes Ab | Construction | 2025 |
| Oy Länsirannikon eläinklinikka - Västkustens djurklinik Ab | Professional & scientific | 2020 |
| Oy Löffe Ab | Arts & recreation | 2021 |
| Oy M&M Catering Ab | Hospitality | 2017 |
| Oy MIRCHI MASALA Ab | Hospitality | 2023 |
| Oy MR Capital Ab | Financial services | 2007 |
| Oy Magokoro Ab | Hospitality | 2010 |
| Oy Mainos-Reklam Peter Lundström Ab | Professional & scientific | 1981 |
| Oy Mainostoimisto Bock's Office Ab | Professional & scientific | 1989 |
| Oy Manor Invest Ab | Financial services | 2004 |
| Oy Melior Pharma Ab | Professional & scientific | 2019 |
| Oy Mente Marine Ab | Professional & scientific | 1993 |
| Oy Merinova Ab | Professional & scientific | 1989 |
| Oy Micky Björkholm Trading Ab | Wholesale & retail | 1983 |
| Oy Mikael Orlo Ab | Hospitality | 2012 |
| Oy Multitronic-JNT Ab | Wholesale & retail | 2017 |
| Oy Mutantti Ltd | Wholesale & retail | 1990 |
| Oy My CapiTall Ab | Financial services | 2026 |
| Oy NST Team Ab | Wholesale & retail | 1998 |
| Oy Namento Ab | Professional & scientific | 1996 |
| Oy Nelsons Cykel & TV Ab | Wholesale & retail | 1982 |
| Oy NetTicket Finland Ab | Administrative & support | 1995 |
| Oy NiceThings Ab | Professional & scientific | 2009 |
| Oy Nordic Chartering Ab | Transport & logistics | 2024 |
| Oy Nordic Know-How Ab | Professional & scientific | 1985 |
| Oy Nordwest Engineering Ab Ltd | Professional & scientific | 2008 |
| Oy Norrgård Legal Consulting Ab | Professional & scientific | 2003 |
| Oy Nyrkkipyykki Ab | Arts & recreation | 2024 |
| Oy ORTOKORPI Ab | Health & social care | 2012 |
| Oy OUR Estates Ltd Ab | Real estate | 2021 |
| Oy Olmari Ab | Information & communication | 2019 |
| Oy Optima LKV Ab | Real estate | 2013 |
| Oy Pekka Lind Ab | Professional & scientific | 1980 |
| Oy Polyplan Ab | Professional & scientific | 1993 |
| Oy Prima Löv Kiinteistöt-Fastigheter Ab | Real estate | 1997 |
| Oy Primo Finland Ab | Manufacturing | 1985 |
| Oy Produktions Good Ltd | Arts & recreation | 2002 |
| Oy Project BeSt Ab | Professional & scientific | 2020 |
| Oy Qvarcomm Ab | Construction | 1996 |
| Oy R.J. Ångerman Ab | Professional & scientific | 1989 |
| Oy RB Tribe Ab | Wholesale & retail | 2022 |
| Oy RBB Rakennus Bygg Ab | Construction | 2018 |
| Oy Rakennus Viiru Ab | Construction | 2002 |
| Oy Rakennuspalvelu G. West Byggtjänst Ab | Construction | 1998 |
| Oy Rakennussuunnittelu AK-Plan Byggnadsplanering Ab | Professional & scientific | 1986 |
| Oy Rengashuolto Lytz Ringservice Ab | Wholesale & retail | 2014 |
| Oy Restorm Ab | Hospitality | 2021 |
| Oy Revente Ab | Real estate | 1973 |
| Oy Risk Consult Ab | Professional & scientific | 1987 |
| Oy Roach Ab | Wholesale & retail | 1981 |
| Oy Rune Sundman Ab | Financial services | 1980 |
| Oy Runsorin EnergyCut Ab | Financial services | 2011 |
| Oy Runsorin Powercut Ab | Financial services | 2004 |
| Oy Runsorin Shortcut Ab | Financial services | 2007 |