| LL-Monipalvelu Oy | Construction | 1995 |
| LLK house Oy | Construction | 2008 |
| LPH Fund I Oy | Financial services | 2022 |
| LPH Invest Oy | Financial services | 2020 |
| LPT PROD Ky | Construction | 2017 |
| LSMT Group Oy | Construction | 2011 |
| LTJ Service Oy | Manufacturing | 2021 |
| Luminardo OY | Real estate | 1985 |
| LUNS Oy | Information & communication | 2024 |
| LV-Fishing Oy | Agriculture & fishing | 2010 |
| LV-Rekry Oy | Administrative & support | 2018 |
| LVI- JaRa Oy | Construction | 2023 |
| LVI-Kupiainen Oy | Construction | 2021 |
| LVI-Palvelu Ilmarinen Oy | Construction | 2017 |
| LVI-Sukeva Oy | Construction | 2022 |
| LVI-Säätö Nyholm Oy | Construction | 1991 |
| LVI-Tekniikka K. Helin Ky | Professional & scientific | 2008 |
| LVI-Vuorinen Oy | Professional & scientific | 2026 |
| LVI-asennus J. Tuominen Oy | Construction | 2025 |
| LVI-insinöörit Oy, HSV | Professional & scientific | 1983 |
| LVI-suunnittelu Haavisto Oy | Professional & scientific | 2007 |
| LVI-suunnittelu Kiviheimo Oy | Professional & scientific | 2025 |
| LaPeso Oy | Wholesale & retail | 2022 |
| Laattacenter Oy Pori | Wholesale & retail | 1988 |
| Laelma Engineering Oy | Professional & scientific | 2012 |
| Lagaro-Music Oy | Hospitality | 2014 |
| Lahdenjärven vesiosuuskunta | Water & waste | 2008 |
| Lahja-Silta Ky | Wholesale & retail | 1990 |
| Laineen Kukka Avoin yhtiö | Wholesale & retail | 2011 |
| Laineiden Flow Oy | Financial services | 2023 |
| Laineiden Voima Oy | Financial services | 2024 |
| LaippaLeevi Oy | Professional & scientific | 2025 |
| Laite- ja Sammutinhuolto Salli Ky | Manufacturing | 1996 |
| Laitekumppanit Oy | Real estate | 1995 |
| Laiteosa J&J Oy | Wholesale & retail | 2026 |
| Lajuve Oy | Financial services | 2025 |
| Lakaja Oy | Transport & logistics | 2022 |
| Lakari Park Oy | Real estate | 2026 |
| Lakerock Oy | Financial services | 2026 |
| Lakiasiaintoimisto Aki Nummelin Oy | Professional & scientific | 2022 |
| Lakiasiaintoimisto Ilpo Pirilä Ky | Professional & scientific | 1998 |
| Lakiasiaintoimisto Jylli & Uotila Ky | Professional & scientific | 1992 |
| Lakiasiaintoimisto Kalevi Paassilta Ky | Professional & scientific | 1986 |
| Lakiasiaintoimisto Lindholm & Gustafsson Oy | Professional & scientific | 2020 |
| Lakiasiaintoimisto Saarinen & Widbom Oy | Professional & scientific | 2026 |
| Lakiasiaintoimisto Tero Jylli Oy | Professional & scientific | 2025 |
| Lakiasiaintoimisto Toimela Ky | Professional & scientific | 1992 |
| Lakiasiaintoimisto Vivid Oy | Professional & scientific | 2025 |
| Lakiasiaintoimisto Ylikahri Oy | Professional & scientific | 2012 |
| Lalli Oy | Information & communication | 1972 |
| Lampaluodon Vesiosuuskunta | Water & waste | 1993 |
| Lamran Oy | Financial services | 2006 |
| Lanest Oy | Health & social care | 2013 |
| Lanka ja Muovi Oy | Manufacturing | 1964 |
| Lankoski Oy | Wholesale & retail | 1988 |
| Laoma Oy | Financial services | 2019 |
| Lasi ja Peili Hallikainen Oy | Construction | 2025 |
| Lasi- ja Rakennuspalvelu Mäkeläinen Ky | Construction | 2017 |
| Lasitusliike Jalonen Oy | Construction | 2025 |
| Lasitusliike Puurila Oy | Wholesale & retail | 2019 |
| Laspel Oy | Financial services | 2014 |
| Lasten Into Oy | Wholesale & retail | 2016 |
| Lastenpuoti Emppu Ky | Wholesale & retail | 1986 |
| Latkaa Oy | Real estate | 2025 |
| Lattiatyö Linho Oy | Construction | 1994 |
| Lattomeren pienkonehuolto oy | Manufacturing | 2026 |
| Laudens Oy | Health & social care | 2020 |
| Laura Group Oy | Wholesale & retail | 2013 |
| Laura Peltomaa Ky | Education | 2016 |
| Laurila Asunnot Oy | Real estate | 2025 |
| Laurilantien vesiosuuskunta | Water & waste | 2010 |
| LeMeRak Oy | Construction | 2021 |
| LeagueX Oy | Arts & recreation | 2020 |
| Ledi Oy Liiketoiminnan Edistämisinstituutti Ltd | Professional & scientific | 1998 |
| Leenan Mattokutomo avoin yhtiö | Manufacturing | 1994 |
| Leffa Lehtinen Events Oy | Arts & recreation | 2026 |
| Lehtonen & Österlund avoin yhtiö | Wholesale & retail | 1990 |
| Lejupe Oy | Real estate | 1995 |
| Lekasi Invest Oy | Financial services | 2024 |
| Lemicom Oy | Professional & scientific | 2022 |
| Leminen Invest Oy | Real estate | 2019 |
| Lemone Oy | Information & communication | 2026 |
| Lempi Store Oy | Wholesale & retail | 2023 |
| Lepistö Asunnot Oy | Manufacturing | 2023 |
| Leppälammi Ky | Wholesale & retail | 2004 |
| Les Rêve Oy | Professional & scientific | 2024 |
| Level Investment Oy | Real estate | 2004 |
| Level Kiinteistöt 1 Oy | Real estate | 2010 |
| Level Kiinteistöt 2 Oy | Real estate | 2010 |
| Levicon consulting Oy | Professional & scientific | 2021 |
| Li-Plast Kiinteistöt Oy | Real estate | 2004 |
| Li-Plast Oy | Manufacturing | 1976 |
| Light Field Oy | Administrative & support | 2019 |
| Liidilinja Oy | Professional & scientific | 2025 |
| Liiketilat A27B103 Oy | Real estate | 2023 |
| Liinaharjan Autopiste Oy | Other services | 2013 |
| Liinaharjan Leipomo ja Konditoria Oy | Manufacturing | 1993 |
| Liisan Kulma Oy | Real estate | 1994 |
| Lil Plot Oy | Wholesale & retail | 2018 |
| Linadapex Oy | Wholesale & retail | 1993 |