| Väripisara Oy | Administrative & support | 2017 |
| Väylällä Oy | Arts & recreation | 2024 |
| W Holding Oy | Professional & scientific | 2025 |
| W Pop Oy | Construction | 1999 |
| W&M Atlantis Oy | Real estate | 2023 |
| W-homes Oy | Real estate | 2023 |
| W-productions Oy | Arts & recreation | 2019 |
| WE Kiinteistöt Oy | Hospitality | 2023 |
| Wormax OY | Construction | 2011 |
| Wakatipu Oy | Financial services | 2022 |
| Waltfox Oy | Professional & scientific | 2023 |
| Wanha Aalto Oy | Wholesale & retail | 1995 |
| Wanstall Oy | Wholesale & retail | 2025 |
| Warat Oy | Financial services | 2020 |
| Watera Oy | Construction | 2025 |
| Way Homes Oy | Real estate | 2025 |
| Way2Social Oy | Professional & scientific | 2025 |
| WeDoBooks Oy | Information & communication | 2023 |
| WeSolve Oy | Information & communication | 2020 |
| Wedding Garage Oy | Wholesale & retail | 2018 |
| Weeefiner Oy | Water & waste | 2017 |
| Weightless World osk | Information & communication | 2019 |
| Weiling Oy | Construction | 2020 |
| WellWorks Oy | Information & communication | 1996 |
| Welldone Group Oy | Construction | 2019 |
| Wellness Sari Holopainen Oy | Other services | 2011 |
| Wellpro Impact Solutions Oy | Information & communication | 2021 |
| West East Oy | Professional & scientific | 2021 |
| West-Africa-Finland Investment Oy | Professional & scientific | 2017 |
| WestWind Kauniskangas Oy | Energy | 2019 |
| WestWind Konnevesi Oy | Energy | 2023 |
| WestWind Oy | Manufacturing | 2021 |
| WestWind Palkkikangas Oy | Energy | 2022 |
| WestWind Pirtti-Moskuva Oy | Energy | 2021 |
| WestWind Siirto Keuruu Oy | Energy | 2022 |
| WestWind Siirto Oy | Energy | 2021 |
| WestWind Solar Keuruu Oy | Construction | 2022 |
| WestWind Solar Kinnula Oy | Energy | 2023 |
| WestWind Solar Kivineva Oy | Energy | 2023 |
| WestWind Solar Kummunsuo Oy | Energy | 2023 |
| WestWind Solar Kyyjärvi Oy | Energy | 2023 |
| WestWind Solar Nuupas Oy | Energy | 2023 |
| WestWind Solar Sihveri Oy | Energy | 2023 |
| WestWind Solar Tompseli Oy | Energy | 2023 |
| WestWind Solar Virosensuo Oy | Energy | 2023 |
| WestWind Solar Vuolijoki Oy | Energy | 2023 |
| WestWind Vahanka Oy | Energy | 2022 |
| WestWind Vehkaneva Oy | Energy | 2022 |
| WestWind Vihuri Oy | Energy | 2023 |
| Westend Consulting Oy | Professional & scientific | 2025 |
| White Tiger Service Oy | Professional & scientific | 1991 |
| WhiteHouse Trading Oy | Financial services | 2026 |
| Whoco Oy | Professional & scientific | 2019 |
| Wide Asset Oy | Financial services | 2003 |
| Wiilinki Oy ohjaus ja valmennus | Professional & scientific | 2020 |
| Wilhealth Oy | Health & social care | 2020 |
| Willman's Catering Oy | Hospitality | 2018 |
| Willpuu Oy | Manufacturing | 2015 |
| Wilmactor Oy | Financial services | 2017 |
| WinTech Oy | Professional & scientific | 2006 |
| Windfarm Kaijansuo Oy | Energy | 2024 |
| Windfarm Kairineva Oy | Energy | 2024 |
| Windfarm Kynkäänsuo Oy | Energy | 2024 |
| Windfarm Palloneva Oy | Energy | 2024 |
| Wisdomus Oy | Information & communication | 2019 |
| Witinos Oy | Financial services | 2021 |
| Wok Star Oy | Hospitality | 2026 |
| Wolapro Oy | Professional & scientific | 2024 |
| Woodponen Oy | Real estate | 2019 |
| Woodspin Oy | Manufacturing | 2021 |
| Woolman Oy | Information & communication | 2017 |
| Woolman Stars Oy | Information & communication | 2025 |
| Wopo Oy | Administrative & support | 2022 |
| Work Cars Oy | Wholesale & retail | 2014 |
| Works & Visuals Oy | Professional & scientific | 2025 |
| WorldMart Oy | Wholesale & retail | 2026 |
| Worldwide Laserservice Oy | Manufacturing | 2018 |
| Wristy Holdings Oy | Financial services | 2025 |
| WulfaWear Oy | Information & communication | 2023 |
| XPM Precision Oy | Financial services | 2026 |
| XR Marine Oy | Information & communication | 2020 |
| Xenomer Oy | Wholesale & retail | 2005 |
| Xvan Oy | Wholesale & retail | 2026 |
| Y&V Urakointi Oy | Transport & logistics | 2023 |
| YM-Kiinteistöt Oy | Wholesale & retail | 1993 |
| YSP-Yleinen Sähköpalvelu Oy | Professional & scientific | 1985 |
| YTT Perustus ja Asennus Oy | Construction | 2026 |
| Yafei Oy | Hospitality | 2021 |
| Yalaho Capital Oy | Arts & recreation | 2026 |
| Yhtyneet Talotehtaat Oy | Construction | 2020 |
| Yinvest Oy | Financial services | 2016 |
| Ykspetäjä Oy | Transport & logistics | 1981 |
| Ykspuinen Oy | Real estate | 1977 |
| YliPuhdas Oy | Administrative & support | 2021 |
| Ylä-Savon Tervavene Oy | Professional & scientific | 2002 |
| Yohina Business Management Oy | Professional & scientific | 2025 |
| Yohina Capital Oy | Financial services | 2019 |
| Yohina Motorsport Oy | Education | 2022 |
| Yonggang Oy | Hospitality | 2020 |
| Young Investor's Oy | Financial services | 2010 |