| Kuhlbergs byggservice Ab Oy | Construction | 2013 |
| Kuljetus Janne Salminen Oy | Transport & logistics | 2010 |
| Kumar's Invest Ab | Financial services | 2020 |
| Kvarnbacken Invest Ab | Real estate | 2008 |
| Kvarnviken Ab | Financial services | 2012 |
| Kvartersbageriet Ab | Hospitality | 2021 |
| Ky Appelgren Kb | Manufacturing | 1979 |
| Ky B Ray Kb | Wholesale & retail | 1986 |
| Ky Medi Rehab Erkki Laihorinne Kb | Health & social care | 1979 |
| Kärkimalli Oy | Manufacturing | 1988 |
| L & A Tjänster Ab | Administrative & support | 2019 |
| L39 Ventures Oy Ab | Professional & scientific | 2014 |
| LE Rental Oy Ab | Construction | 2019 |
| LFX Invest Oy Ab | Financial services | 2007 |
| LHM Invest Ab Oy | Real estate | 2025 |
| LP-Trader Oy | Real estate | 2016 |
| LPH-Assembly Oy | Manufacturing | 2019 |
| LS Family Invest Ab | Financial services | 2021 |
| LUNA Familjecenter Ab | Health & social care | 2011 |
| Laaja Arkitekter Ab | Professional & scientific | 2009 |
| Laesh Oy Ab | Wholesale & retail | 2012 |
| Laivacon Ab Oy | Construction | 2018 |
| Lakiasiaintoimisto Eliisa Gädda Oy | Professional & scientific | 2012 |
| Larsmo Ullförädling Ab | Manufacturing | 2018 |
| Latini. L. Ab Oy | Professional & scientific | 2022 |
| Leif och Sven Nilsströms Minkfarm | Agriculture & fishing | 1979 |
| Leopold & Sandström | Other services | 2016 |
| Les amis d'Astérix Ltd. Oy | Professional & scientific | 2024 |
| Lextera Law Ab Oy | Professional & scientific | 2019 |
| Liisan Pizza Oy | Hospitality | 2008 |
| Liljestrands Pälsfarm Ab | Agriculture & fishing | 1982 |
| Lilla Ukraina Ab | Hospitality | 2023 |
| Lillsandö och Storsandö Vattenandelslag | Water & waste | 2003 |
| Lind, Höglund & Partners Ab | Professional & scientific | 2006 |
| Local Smash'D Oy | Hospitality | 2023 |
| Logics Oy | Information & communication | 2023 |
| Logmit Ab Oy | Manufacturing | 2020 |
| Lokalförmån Lähietu öppet bolag | Professional & scientific | 2016 |
| Lundström Korporationer Ab | Professional & scientific | 2020 |
| Luxas Group Ab Oy | Financial services | 2024 |
| Luxas Labs Ab Oy | Professional & scientific | 2019 |
| Lysarholmens vattenandelslag | Water & waste | 2000 |
| Låsfix Ab | Wholesale & retail | 2023 |
| Létaste Oy | Wholesale & retail | 2013 |
| M & D Fix Oy Ab | Administrative & support | 2019 |
| M & D Lifestyle Ab | Professional & scientific | 2015 |
| M & M Electric Ab | Construction | 2010 |
| M & M Forsbacka Oy Ab | Wholesale & retail | 2017 |
| M. Holmstedt Ab | Construction | 2020 |
| M.R.P Trading Oy | Wholesale & retail | 1992 |
| MANITO Invest Ab Oy | Real estate | 2019 |
| MAserv Oy | Manufacturing | 2020 |
| MB Textilshoppen Ab | Wholesale & retail | 2010 |
| MEKA Partner Ab | Professional & scientific | 2020 |
| MEL Holding Ab | | 2026 |
| MGA Fix Ab | Construction | 2025 |
| MI-Metall Oy | Wholesale & retail | 1998 |
| MKM Solutions Ab Oy | Real estate | 2018 |
| ML & RH Invest Ab Oy | Real estate | 2021 |
| ML Tax Consulting Ab Oy | Professional & scientific | 2021 |
| MM Byggservice Ab Oy | Construction | 2025 |
| MPK Service Kommanditbolag | Construction | 2009 |
| MRA Makisu Oy Ab | Hospitality | 2010 |
| MT Edustus Oy | Wholesale & retail | 2021 |
| MT Målartjänst öppet bolag | Construction | 2015 |
| MZ Autoparsinta Oy | Other services | 2022 |
| MZ-Tech Ab Oy | Administrative & support | 2023 |
| Maalaamo Kanerva Oy | Construction | 1987 |
| Maans & Lindh öppet bolag | Arts & recreation | 2019 |
| MacLin Oy Ab | Administrative & support | 2020 |
| Magnus Gunn Ab | Professional & scientific | 2020 |
| Malmska Fastigheter Ab | Real estate | 2025 |
| Mangleis Group Ab Oy | Professional & scientific | 2020 |
| Mannström Invest AB | Wholesale & retail | 2016 |
| Mannströms fastighets ab | Construction | 2020 |
| Manofi Holding AB | Financial services | 2008 |
| Maple Invest Ab | Financial services | 2021 |
| Marble Ltd Ab | Wholesale & retail | 1995 |
| Maria Terapi Ab | Health & social care | 2017 |
| Marketor Svahn Ky | Wholesale & retail | 1991 |
| Marks & Iris Ab | Wholesale & retail | 2023 |
| Martekons Oy Ab | Manufacturing | 1987 |
| Marula Hair Salon Ab | Other services | 2019 |
| Massage Punkten Jakobstad Ab | Health & social care | 2011 |
| Matin Pizzeria Oy | Hospitality | 2013 |
| Mats Åkerholm Ab Oy | Wholesale & retail | 2008 |
| Mattsson Invest Ab | Real estate | 2019 |
| Maxifun Ab Oy | Arts & recreation | 2014 |
| McGowans Ab | Real estate | 2024 |
| MedRehab Oy | Health & social care | 2009 |
| MediPunkt Öppet bolag | Administrative & support | 2006 |
| Mega Team avoinyhtiö | Hospitality | 1998 |
| Mekano Fastighets Ab | Real estate | 2008 |
| Mekrapid Products Ab | Manufacturing | 1983 |
| Meneli Ab | Health & social care | 2015 |
| Mesko Purkupalvelu Oy | Construction | 2020 |
| Messina Oy Ab | Hospitality | 2010 |
| MetallTek Wiklund Ab | Manufacturing | 2020 |
| Mia ja Mikael Rimmi Oy | Wholesale & retail | 2006 |
| Mictech Ab | Professional & scientific | 2019 |