| Oy Rönn Gräv och Transport Ab | Construction | 1997 |
| Oy SaMa Kukkasitomo Ab | Wholesale & retail | 2017 |
| Oy Saippuan-Ranta - Tvålens-Strand Ab | Real estate | 1897 |
| Oy Sallan Kopsu | Real estate | 1990 |
| Oy Scandinavian Digital Ab | Information & communication | 1992 |
| Oy Selected Goods Ab | Wholesale & retail | 2017 |
| Oy Seres Ab | Professional & scientific | 2008 |
| Oy Sewreon Ltd | Manufacturing | 2025 |
| Oy Sicuro Ab | Financial services | 1988 |
| Oy Sjoba Ab | Other services | 2023 |
| Oy Skandia Lattia - Golv Ab | Construction | 2006 |
| Oy SkinMate Ab | Health & social care | 2012 |
| Oy Skrinet Ab | Information & communication | 2006 |
| Oy Slotte Investment Ab | Real estate | 2000 |
| Oy Sloyd Ab | Construction | 1994 |
| Oy Soinin Tuuli Ab | Energy | 2013 |
| Oy Stall Domino Ab | Arts & recreation | 2010 |
| Oy Stamec Ab | Manufacturing | 2007 |
| Oy Star Communications Ab | Professional & scientific | 2026 |
| Oy Steven Holding Ab | Financial services | 2022 |
| Oy Stigmed Ab | Health & social care | 1988 |
| Oy Strömsö Business Consulting Ab | Professional & scientific | 2022 |
| Oy Studio Fotocenter Ab | Professional & scientific | 1986 |
| Oy Studio Ticket Ab | Administrative & support | 2014 |
| Oy Sundaco Ab | Information & communication | 1996 |
| Oy Suomen Valokyltti Ab | Professional & scientific | 2012 |
| Oy Suomen Vuorikone Ltd | Construction | 1997 |
| Oy Sähkö Test Vaasa | Professional & scientific | 1990 |
| Oy TR Interior Design Ab | Professional & scientific | 1991 |
| Oy TSR Sporting Ltd | Wholesale & retail | 2021 |
| Oy Taala Invest Ab | Professional & scientific | 1987 |
| Oy Talo & Keittiö - Hus & Kök Svahn Ab | Wholesale & retail | 1985 |
| Oy Talous-Ami Ab | Professional & scientific | 1997 |
| Oy Tili-Konto Ab | Professional & scientific | 1964 |
| Oy Tilitoimisto Kontroll Bokföringsbyrå Ab | Professional & scientific | 2011 |
| Oy TipTop Service Ab | Construction | 2022 |
| Oy Toby Park Ab | Wholesale & retail | 1995 |
| Oy Toby Power AB | Wholesale & retail | 2019 |
| Oy Toimialakirjanpito-Branschbokföring Ab | Professional & scientific | 1989 |
| Oy Tom & Tom Ab | Other services | 2001 |
| Oy Tom Knip Ab | Construction | 1993 |
| Oy Torgmästars Ab | Wholesale & retail | 2013 |
| Oy Truckman Trade Ab | Wholesale & retail | 1992 |
| Oy Tyfon Ab | Wholesale & retail | 2001 |
| Oy UmbraFex LTD | Professional & scientific | 2025 |
| Oy VKY-Palvelu Ab | Professional & scientific | 2007 |
| Oy Vaasa Insider Ab | Information & communication | 2017 |
| Oy Vaasahuolinta - Vasaspedition Ab | Transport & logistics | 1989 |
| Oy Vaasan Asumisoikeus-Vasa Bostadsrätt Ab | Real estate | 1992 |
| Oy Vaasan Autopaikka Ab | Other services | 1994 |
| Oy Vaasan Ekolämpö-Vasa Ekovärme Ab | Energy | 1987 |
| Oy Vaasan Eläinkeskus - Vasa Djurcentrum Ab | Wholesale & retail | 1995 |
| Oy Vaasan Hautaustoimisto - Vasa Begravningsbyrå Ab | Other services | 1983 |
| Oy Vaasan JK-Putkityö Ab | Construction | 2000 |
| Oy Vaasan Joutsen Ab | Hospitality | 1978 |
| Oy Vaasan Kiinteistömyynti - Vasa Fastighetsförsäljning Ab | Real estate | 1985 |
| Oy Vaasan Klubi Ravintola | Hospitality | 1994 |
| Oy Vaasan Kotilääkärit Vasa Husläkare Ab | Health & social care | 2001 |
| Oy Vaasan Kuorma-autopalvelu - Vasa Lastbilstjänst Ab | Transport & logistics | 1964 |
| Oy Vaasan Luonnonravinto-Vasa Naturkost Ab | Wholesale & retail | 2009 |
| Oy Vaasan Pelaajapörssi - Vasa Spelarbörs Ab | Arts & recreation | 1992 |
| Oy Vaasan Rinki Ab | Transport & logistics | 2006 |
| Oy Vaasan SPAB-kiinteistö | Real estate | 2007 |
| Oy Vaasan Saaristopalvelu Vasa Skärgårdservice Ab | Hospitality | 1995 |
| Oy Vaasan Säästölämpö Ab | Energy | 1965 |
| Oy Vaasan Toripysäköinti - Vasa Torgparkering Ab | Transport & logistics | 1991 |
| Oy Vaasan Vihannes - Vasa Grönsaker Ab | Wholesale & retail | 1963 |
| Oy Vaasan ammattikorkeakoulu - Vasa yrkeshögskola Ab | Education | 2009 |
| Oy Vasa Alu-Trading Ab | Wholesale & retail | 1994 |
| Oy Vaskiluodon Autohuolto - Vasklot Bilservice Ab | Other services | 2020 |
| Oy Victor Doctorzon Ab | Health & social care | 2008 |
| Oy Villen Parketti - Villes Parkett Ab | Construction | 1993 |
| Oy WH Invest Ltd | Financial services | 2008 |
| Oy WM International Ab | Manufacturing | 1994 |
| Oy Wasa Design Ab | Wholesale & retail | 2017 |
| Oy Wasa Juridia & Invest Ab | Financial services | 1986 |
| Oy Wasa ST-Invest Ltd | Real estate | 2009 |
| Oy Wasa Stock Adviser Ab | Financial services | 2007 |
| Oy Wasa Up Ab | Arts & recreation | 2017 |
| Oy Wasa Yachting Club Ab | Real estate | 1993 |
| Oy Wasasafe Ab | Wholesale & retail | 1992 |
| Oy Wasaware Ab | Wholesale & retail | 1989 |
| Oy Wedeco Ab | Financial services | 1988 |
| Oy West Investing Ab | Professional & scientific | 2025 |
| Oy West Vuokrahallit - Hyreshallar Ab | Real estate | 2003 |
| Oy WestCoat Ab | Wholesale & retail | 2025 |
| Oy Winjet Ab | Wholesale & retail | 2004 |
| Oy Winpos Ab | Information & communication | 1997 |
| Oy YBAS Ab | Professional & scientific | 2019 |
| Oy Yrittävä Vaasa Ab | Administrative & support | 2015 |
| Oy af Lång Ab | Construction | 2023 |
| Oy Ädelsten Ab | Professional & scientific | 2003 |
| Oy Österberg Ab | Manufacturing | 1990 |
| P.P.Eerola Ky | Construction | 2014 |
| PARO Boats Ab Oy | Other services | 1996 |
| PE Eränen Oy | Professional & scientific | 1967 |
| PJI Trading Oy | Transport & logistics | 2012 |
| PJP Metalli Oy | Manufacturing | 2021 |
| PJW Group Oy | Professional & scientific | 2022 |
| PK-Talousratkaisut Oy | Professional & scientific | 2014 |