| Oy Strateg - Loyalty Finland Ab | Professional & scientific | 2003 |
| Oy Stråhlmann Yacht Design Ab | Professional & scientific | 2007 |
| Oy Suntimo Ab | Real estate | 1992 |
| Oy Suomen EDM Ab | Manufacturing | 1980 |
| Oy T.Salakari Ab | Construction | 2008 |
| Oy TKR-Coatings Ltd | Professional & scientific | 1997 |
| Oy Tapani-Keittiöt Ab | Financial services | 1990 |
| Oy Tapuli Holding Ab | Real estate | 1994 |
| Oy Tarmolan kotileipomo Ab | Manufacturing | 1995 |
| Oy TerraMarina Ab | Real estate | 2015 |
| Oy Tilitoimisto Lindroos Bokföringsbyrå Ab | Professional & scientific | 1983 |
| Oy Tolkkisten Sähkö Ab | Construction | 2005 |
| Oy Tor Frejborg Ab | Transport & logistics | 1990 |
| Oy Tracebit Ab | Professional & scientific | 1997 |
| Oy Ulf Stenströms bilmåleri Ab | Other services | 2005 |
| Oy Uudenmaan Maalaus & Siivous Ab | Construction | 2004 |
| Oy VIG Huolto-Service Ab | Administrative & support | 2012 |
| Oy Vintertec Offshore Ltd | Construction | 1989 |
| Oy Wesstech Plast Ab | Wholesale & retail | 1995 |
| Oy Westmanns Ab | Transport & logistics | 2022 |
| Oy Winnski Finland Ab | Wholesale & retail | 1995 |
| Oy X-Ray Ab | Arts & recreation | 1977 |
| P-merkki Oy | Manufacturing | 1993 |
| P. Salo Oy | Administrative & support | 2019 |
| P.Bomanin Kaivin & Gräv Oy Ab | Construction | 2006 |
| P.O. Spring Hill Oy | Wholesale & retail | 2018 |
| PAREBO Oy | Construction | 2026 |
| PE Development Oy | Construction | 2018 |
| Pharmbiotech OY | Professional & scientific | 2012 |
| PHI-Invest Oy | Financial services | 2019 |
| PK Engineering Oy | Other services | 2016 |
| PK Koivisto Oy | Construction | 2011 |
| PKM Vahinkokartoitus Oy | Construction | 2014 |
| PL-Rakennus Oy Pekka Lindblad | Construction | 2000 |
| PMK Holding Oy | Real estate | 2017 |
| Porvoon Autokorjaamo OY | Other services | 2011 |
| Porvoon Henkilöstöravintola Rosmariini OY | Hospitality | 2011 |
| Pot-De-Vin OY | Wholesale & retail | 2010 |
| Power X System OY | Professional & scientific | 2020 |
| PP Coaching & Consulting Oy | Professional & scientific | 1993 |
| PPD Group Oy | Professional & scientific | 1989 |
| PR Coding Oy | Professional & scientific | 2022 |
| PR-Services Oy Hanna Kaarina | Professional & scientific | 1993 |
| PS Sijoitus Oy | Administrative & support | 2011 |
| PS-Kiinteistöt Oy | Real estate | 1993 |
| PSK-Tarrat Oy | Wholesale & retail | 1995 |
| PSV Holding Oy Ab | Real estate | 2020 |
| PT Projects Oy | Real estate | 2020 |
| PTH-Metalli Oy | Manufacturing | 2019 |
| Punatähti OY | Professional & scientific | 2025 |
| PW Group Oy | Construction | 2016 |
| PYSTYMETSÄ Oy | Information & communication | 1997 |
| PaTa Solutions Oy | Hospitality | 2012 |
| Paasio & Partners Oy | Financial services | 2025 |
| Padel Arena Porvoo Oy | Arts & recreation | 2020 |
| Pahajoki Capital Oy | Information & communication | 2020 |
| Paikallaan Oy | Health & social care | 2024 |
| Painotalo TK Oy | Wholesale & retail | 1992 |
| Pakkaus-Broman Oy | Wholesale & retail | 2023 |
| Papajholding Oy | Financial services | 2024 |
| Paperipilvi Oy | Wholesale & retail | 2019 |
| Papinniemi Oy | Manufacturing | 1995 |
| Pappa betalar inte Oy | Financial services | 2024 |
| Paris-Helsinki Oy | Professional & scientific | 2014 |
| Pariza Products Oy | Hospitality | 2014 |
| Parketti Appel Ky | Construction | 1990 |
| Parrotstreet Oy | Wholesale & retail | 2024 |
| Parturi Pääpäivä Oy | Other services | 2021 |
| Party Porvoo Oy | Hospitality | 2022 |
| Parviainen Coaching & Consulting Ky | Professional & scientific | 2012 |
| Pasi Rautiainen Management ky | Professional & scientific | 2005 |
| Pasi Volanen Oy | Real estate | 1993 |
| Patim Oy | Construction | 2002 |
| Pavex Trading Oy | Wholesale & retail | 2026 |
| Peakan Oy | Real estate | 2013 |
| Peerland Oy | Education | 2006 |
| Pekka Suominen Oy | Information & communication | 2010 |
| Peksin pirssi Oy | Transport & logistics | 2018 |
| Pelax Oy | Administrative & support | 2025 |
| Pella Valla Oy | Manufacturing | 2019 |
| Pellinge Marina Oy | Other services | 2021 |
| Pelmes Oy | Real estate | 1989 |
| Peltinavetta Oy | Manufacturing | 2021 |
| Peltola Medical Oy | Health & social care | 2020 |
| Peltola Racing Service Oy | Other services | 2009 |
| Pemira Oy | Construction | 2021 |
| People´s Village Oy | Professional & scientific | 1989 |
| Pepe-Tricks Oy | Wholesale & retail | 2011 |
| Pepen palvelut Oy | Education | 1996 |
| Perfect Palvelut Oy | Transport & logistics | 2025 |
| Perhekoti Eemeli Oy | Health & social care | 2021 |
| Perhekoti Väri Oy | Health & social care | 2025 |
| Perinnerakentaja Simo Laurila Oy | Construction | 2018 |
| Peroset Oy | Manufacturing | 2019 |
| Personal Training Pysy Elossa Oy | Arts & recreation | 1990 |
| Pesola Training Oy | Professional & scientific | 2013 |
| Petaisto Oy | Arts & recreation | 2020 |
| Pete's Craft Oy | Construction | 2012 |
| Peten Golfvaruste Oy | Wholesale & retail | 1993 |
| Peter ja Niina Fransman Oy | Wholesale & retail | 2001 |