| Nummila Holding Oy | Financial services | 2024 |
| Nuohous ja Ilmastointipalvelu Lehtinen Ky | Administrative & support | 2006 |
| NuoriNurmi Oy | Other services | 2025 |
| Nupumies Oy | Transport & logistics | 1993 |
| Nygård People & Performance Oy | Professional & scientific | 2026 |
| O.Y. Skrobb A.B. | Real estate | 1941 |
| OEE Holding Oy | Financial services | 2021 |
| OK-Tuotanto Oy | Arts & recreation | 2020 |
| OY M.R. Kaivuu-Kuljetus AB | Construction | 2007 |
| Oivalto Oy | Information & communication | 2011 |
| Old Style Service & Restoration Oy | Manufacturing | 2012 |
| Onecon Oy | Construction | 2022 |
| Onnicare Oy | Health & social care | 2026 |
| Optiopaja Oy | Financial services | 1987 |
| Optis Invest Oy | Financial services | 2017 |
| Origo Isännöinti Oy | Real estate | 2020 |
| Osakeyhtiö A & E Lähteenmäki | Professional & scientific | 1989 |
| Osuuskunta Onni-Inno Ok | Education | 2002 |
| Osuuskunta Puukilta | Construction | 2012 |
| Osuva Design Oy | Administrative & support | 2023 |
| Otsonpesä Oy | Education | 2011 |
| Oxvik Oy | Professional & scientific | 2019 |
| Oy Ajando Ab | Real estate | 2022 |
| Oy Alakoski & Alakoski Ab | Real estate | 1991 |
| Oy Amihima Ab LKV | Real estate | 1991 |
| Oy Auto Ljungqvist Bil Ab | Other services | 1987 |
| Oy Byra Ab | Construction | 1995 |
| Oy E. Walander Ab | Construction | 1994 |
| Oy Emmahus Ab | Construction | 2012 |
| Oy Esdata Ab | Information & communication | 2009 |
| Oy Fioton Ab | Construction | 1997 |
| Oy Fiskal Ab | Real estate | 2010 |
| Oy Göran Hagelberg Ab | Construction | 1974 |
| Oy HGG-Yhtiö Ab | Real estate | 1994 |
| Oy Hit-Hair Ab | Other services | 1995 |
| Oy Huoltoliike L Malmberg Ab | Other services | 1989 |
| Oy Imporex Ab | Professional & scientific | 1989 |
| Oy Ingenjörsbyrån Diagner Ab/Oy Insinööritoimisto Diagner Ab | Information & communication | 1998 |
| Oy Ingvald Lindberg Ab | Transport & logistics | 1990 |
| Oy Jeggars Ab | Wholesale & retail | 2016 |
| Oy K. Rehn Ab | Other services | 1984 |
| Oy Kai-Bel Ab | Wholesale & retail | 1993 |
| Oy Kansainvälinen Lakitoimisto Europa Ltd SA | Professional & scientific | 1995 |
| Oy Kevätniemi | Real estate | 1933 |
| Oy Kirkkonummen Ahtaus Ab | Transport & logistics | 1980 |
| Oy Korpikangas Siemen-Frö Ab | Wholesale & retail | 1993 |
| Oy Kristec Ab | Wholesale & retail | 1990 |
| Oy L.U.G. Consulting Ab | Professional & scientific | 1986 |
| Oy Leforsbe Ab | Professional & scientific | 2005 |
| Oy Leif Lindberg Ab | Transport & logistics | 1991 |
| Oy Lillvik Ab | Financial services | 2021 |
| Oy Motivum Ab Ltd. | Wholesale & retail | 1997 |
| Oy MotoHot Mechanics Ab | Other services | 2022 |
| Oy Mustion Murske Ab | Real estate | 1995 |
| Oy Nordic Sales Key Ab | Professional & scientific | 2020 |
| Oy Nuddex Ab | Professional & scientific | 1994 |
| Oy Ounastapio | Real estate | 1984 |
| Oy Parartisto Ab | Professional & scientific | 1995 |
| Oy Peders Gård Ab | Real estate | 2009 |
| Oy Peteratek Ab | Other services | 1990 |
| Oy Peuramaa Golf Hjortlandet Golf Ab | Arts & recreation | 1991 |
| Oy Peuramaa-Hjortlandet Ab | Real estate | 1992 |
| Oy Pineus Ab | Financial services | 1989 |
| Oy Porkkalan Puhdistuspalvelu Ab | Administrative & support | 2007 |
| Oy Porkkalan Viisikulma Ab | Real estate | 1991 |
| Oy Power People Finland Ltd | Professional & scientific | 2006 |
| Oy RW-Invest Ab | Professional & scientific | 1993 |
| Oy Rixon Ab | Agriculture & fishing | 1997 |
| Oy Salon Tomas Ab | Other services | 1993 |
| Oy Scanteknik Ab | Wholesale & retail | 1993 |
| Oy Sevifi Ab | Administrative & support | 2007 |
| Oy Shinbo Ab | Professional & scientific | 1986 |
| Oy Stallgården Astra Ab | Wholesale & retail | 2020 |
| Oy Suzi Media Production Ltd | Information & communication | 2014 |
| Oy T.I. Lindholm Trans Ab | Transport & logistics | 1976 |
| Oy Takisto Ab | Financial services | 1991 |
| Oy Tunkman Ab | Information & communication | 2022 |
| Oy Ulrika Sjöholm Ab | Professional & scientific | 2008 |
| Oy Vamar Ab | Manufacturing | 1990 |
| Oy W & A Management Ab | Real estate | 2012 |
| PACC Oy | Education | 2023 |
| PDI Services Oy | Manufacturing | 2018 |
| PH-Cervice Oy | Administrative & support | 2010 |
| PK Studio83 Oy | Other services | 2020 |
| PKM Viihdepalvelut Oy | Transport & logistics | 2009 |
| PLOKI Ky | Professional & scientific | 1990 |
| PMH Holding Oy | Financial services | 2019 |
| PTL Rajaton Oy | Construction | 2015 |
| PV Holdings Oy | Financial services | 2010 |
| Padel Northpole Oy | Arts & recreation | 2021 |
| Pahakala Oy | Professional & scientific | 2011 |
| Paketboden Ab | Administrative & support | 2019 |
| Pakkanen Holding Oy | Financial services | 2020 |
| Pantheon Software Oy | Information & communication | 2026 |
| Parkkonen Motorsport Oy | Arts & recreation | 2019 |
| Parkon Innovations Oy | Professional & scientific | 2001 |
| Part-Time Genius Oy | Professional & scientific | 2022 |
| Partsu Oy | Financial services | 2020 |
| Parturi-kampaamo Sateenkaarenpää Oy | Other services | 2014 |
| Patcomp Oy | Wholesale & retail | 2023 |