| K. Rosenström Oy | Transport & logistics | 2014 |
| K.N. Nylund Oy | Construction | 2017 |
| K4-Service Oy | Other services | 2024 |
| KA-Tuonti Oy | Wholesale & retail | 2019 |
| KAAMOS Esports Oy | Arts & recreation | 2020 |
| KAP-Laskenta Oy | Professional & scientific | 2006 |
| KB Taxi Oy | Transport & logistics | 2009 |
| KBL Service Oy | Construction | 2026 |
| KFE Oy | Financial services | 2025 |
| KH Sales Agency Oy | Professional & scientific | 2023 |
| KHH-Service Oy | Administrative & support | 2021 |
| KIMAR Ky | Hospitality | 1998 |
| Kinocolor OY | Information & communication | 2012 |
| Kiranna Ky | Professional & scientific | 2013 |
| KJD Product Invest Inc. Oy | Professional & scientific | 2023 |
| KOY Porvoon Hitsaajantie 1 | Real estate | 2018 |
| KOY Porvoon Koneistajantie 8 | Real estate | 2016 |
| KOY Porvoon Lakkapolku 54 | Real estate | 2017 |
| KOY Porvoon Mestarinkulma | Real estate | 2018 |
| KOY Porvoon Pienteollisuustie 2 | Real estate | 2019 |
| KOY Porvoon Sorvaajantie 12 | Real estate | 2017 |
| KOY Porvoon Työpajatie 12 | Real estate | 2019 |
| KP Catering OY | Hospitality | 2012 |
| KP Mestarit Oy | Construction | 2023 |
| KP-Consult Oy | Wholesale & retail | 1989 |
| Kpax OY | Professional & scientific | 2016 |
| KUux3 Oy | Financial services | 2023 |
| Kahari & Co Eristys Ky | Construction | 1980 |
| Kahvila Torinkulma Oy | Hospitality | 2023 |
| Kaitsun Kala ja Vihannes Oy | Wholesale & retail | 1977 |
| Kaivankos Oy | Construction | 2007 |
| Kajas Investment Oy | Professional & scientific | 1998 |
| Kajasoja Oy | Professional & scientific | 2021 |
| Kajote Oy | Manufacturing | 1960 |
| Kallionporaus Tyyskä Oy | Mining & quarrying | 2019 |
| Kalmed Oy | Administrative & support | 2007 |
| Kalustekisällit Ky | Manufacturing | 1982 |
| Kalvö Kiinteistöt Ky | Construction | 2008 |
| Kamb Catering Oy Ab | Hospitality | 2015 |
| Kampaamo M-L Lehto Ky | Other services | 1984 |
| Kanarianlinnut Capital Oy | Wholesale & retail | 2023 |
| Kanervala Oy | Professional & scientific | 2012 |
| Kannonnokka Events Oy | Administrative & support | 2023 |
| Kapama Oy | Manufacturing | 2021 |
| Karelia Group Oy | Financial services | 2022 |
| Karelia Outdoor Oy | Administrative & support | 2025 |
| Karhusaaren Rakennuspalvelu Oy | Construction | 1997 |
| Karinova Oy | Professional & scientific | 2011 |
| Karlsson Invest Oy | Wholesale & retail | 2020 |
| Karma Capital Oy | Professional & scientific | 2019 |
| Karmas Oy | Professional & scientific | 2005 |
| Karpenteria Oy | Construction | 2007 |
| Kartoituspalvelu Lappalainen Ky | Professional & scientific | 2000 |
| Kasvun Kartano Oy | Health & social care | 2025 |
| Kasvurata Oy | Professional & scientific | 2020 |
| Katto ja rakennus Karhu Oy | Construction | 2020 |
| Kauneus- ja Hyvinvointi SL Oy | Other services | 2022 |
| Kauneuskeskus Loan Dao Oy | Other services | 2022 |
| Kaunissaaren Kala Oy | Agriculture & fishing | 2024 |
| Kausivarasto Tesjoki Oy | Transport & logistics | 2023 |
| Kaverko Oy | Other services | 2015 |
| Kawirak Oy | Construction | 2008 |
| Kb A. Flakholm Ky | Wholesale & retail | 1985 |
| Kb Lovisa Drivers'Loviisa Ky | Education | 2005 |
| Kb Lådfabrik M. Ahlqvist - Laatikkotehdas Ky | Manufacturing | 1983 |
| Kb S-O Backman Ky | Manufacturing | 1996 |
| Keidas Cafe Oy | Hospitality | 2018 |
| Keittiöneuvos Oy | Manufacturing | 2021 |
| Keittiöstudio Palmen Oy | Wholesale & retail | 2026 |
| Kejuca Oy | Professional & scientific | 2021 |
| Kekepaino Oy | Manufacturing | 1982 |
| Kelaj Oy | Hospitality | 2022 |
| Kellosepänliike Karvonen Ky | Wholesale & retail | 1981 |
| Kelluva Kulttuuri Oy | Hospitality | 2022 |
| Kelokiehinen Oy | Real estate | 1989 |
| Kelonen Oy | Wholesale & retail | 2026 |
| Kenkä Tuomala Sko Ky | Wholesale & retail | 1944 |
| Keracomp Oy | Manufacturing | 1983 |
| Keramiikkakone Berglöf & Kni | Manufacturing | 1974 |
| Keravan Kenkä Ky | Wholesale & retail | 1960 |
| Khanhi HM Oy | Other services | 2022 |
| Khukuri Oy | Hospitality | 2016 |
| Kidecon Oy | Professional & scientific | 2019 |
| Kielilähetti Oy | Professional & scientific | 2011 |
| Kiinteistö Heikkerö Oy | Real estate | 2006 |
| Kiinteistö Oy Alapailakka | Real estate | 1995 |
| Kiinteistö Oy Aleksanterinkaaren Pysäköinti | Real estate | 2015 |
| Kiinteistö Oy Gamla Leiha | Administrative & support | 1996 |
| Kiinteistö Oy Haavikkotie 8 | Real estate | 2000 |
| Kiinteistö Oy Hakapörtiö | Real estate | 1972 |
| Kiinteistö Oy Hannuksenpelto 12 | Real estate | 2019 |
| Kiinteistö Oy JR | Real estate | 2005 |
| Kiinteistö Oy Jauratus | Real estate | 1973 |
| Kiinteistö Oy Joikula | Real estate | 1987 |
| Kiinteistö Oy Katajamäki 10 | Real estate | 1994 |
| Kiinteistö Oy Koneistajantie 1 | Real estate | 2012 |
| Kiinteistö Oy Kulmakuja 3 PORVOO | Real estate | 2018 |
| Kiinteistö Oy Leihan Sannanrannan Loma | Real estate | 1999 |
| Kiinteistö Oy Luvian Lohikarit | Real estate | 2000 |
| Kiinteistö Oy Mahlun Millitupa | Real estate | 1998 |