| Mainos-Lehtinen Print KY | Manufacturing | 1983 |
| Market Onnipekka, Heinola Oy | Wholesale & retail | 1973 |
| Markkinointi Hansa Oy | Wholesale & retail | 2012 |
| Markku Suonsyrjä Oy | Real estate | 1990 |
| Matkakoski Oy | Professional & scientific | 1917 |
| Metasan Oy | Manufacturing | 2021 |
| Metsäkonehuolto Kähkönen Oy | Manufacturing | 2014 |
| Miggen Oy | Professional & scientific | 2025 |
| Mivax Oy | Real estate | 2021 |
| Moniurakointi Suomalainen Oy | Construction | 2024 |
| Mortifer Invest Oy | Real estate | 2021 |
| Muovitekniikka Oy Europlast | Manufacturing | 2005 |
| Myllykosken Talli Oy | Agriculture & fishing | 2012 |
| NAKKILAN NAHKIAISPAISTAMO Ky | Wholesale & retail | 2008 |
| Nay Service Finland OY | Construction | 2023 |
| NT In Oy | Manufacturing | 1979 |
| NVH Sähkö Oy | Construction | 1981 |
| NVH-Suunnittelu Oy | Professional & scientific | 1998 |
| Nacre Oy | Manufacturing | 1993 |
| Nafira Oy | Financial services | 1989 |
| Nakkila Engineering Oy | Financial services | 1992 |
| Nakkila Group Oy | Financial services | 1988 |
| Nakkila Works Oy | Manufacturing | 1976 |
| Nakkila-Wear Oy | Real estate | 1981 |
| Nakkilan Autofix Oy | Other services | 2026 |
| Nakkilan Energiaosuuskunta | Energy | 2003 |
| Nakkilan Insinööritoimisto Oy | Professional & scientific | 1989 |
| Nakkilan Isännöinti Oy | Professional & scientific | 1988 |
| Nakkilan Kiinteistöhuolto Oy | Administrative & support | 2006 |
| Nakkilan Konepaja Oy | Manufacturing | 1989 |
| Nakkilan Konesuunnittelu Oy | Professional & scientific | 2002 |
| Nakkilan Koneurakointi Oy | Construction | 2022 |
| Nakkilan MP-Osat Oy | Wholesale & retail | 2014 |
| Nakkilan Metalli Oy | Manufacturing | 2013 |
| Nakkilan NM Kiinteistöt Oy | Real estate | 2013 |
| Nakkilan Osakehuoneistot Oy | Financial services | 1987 |
| Nakkilan Painopalvelu Ky | Manufacturing | 1991 |
| Nakkilan Piha- ja Kiinteistötyö Ky | Administrative & support | 1986 |
| Nakkilan Pyörä ja Mopo Oy | Wholesale & retail | 1990 |
| Nakkilan Rompe Oy | Wholesale & retail | 2025 |
| Nakkilan Sihuma Oy | Construction | 1993 |
| Nakkilan Sähkö ja Radio Ky. | Wholesale & retail | 1987 |
| Naksby Ravintolat Oy | Hospitality | 2024 |
| Nelectric Oy | Construction | 2014 |
| Ninan Parilla Ky | Hospitality | 1989 |
| Nissilä Tech Oy | Construction | 2021 |
| Nordic Plast Oy | Manufacturing | 2020 |
| Nuohous ja ilmastointi Nieminen Oy | Administrative & support | 2021 |
| Nurmen Terästyö Oy | Manufacturing | 1976 |
| Nurte Oy | Real estate | 1992 |
| OHL Construction & Maintenance Oy | Construction | 2024 |
| OHL Services Oy | Professional & scientific | 2023 |
| OP Koti Sataharju Oy LKV | Real estate | 2004 |
| OSA-Trans ky | Transport & logistics | 2001 |
| Owisson Group | Construction | 2022 |
| Owisson Oy | Construction | 2019 |
| Oy Kromatek Ab | Manufacturing | 2014 |
| Oy Rockdale Motors Finland Ltd | Wholesale & retail | 2016 |
| P. Ketola Ky | Transport & logistics | 1994 |
| P. Pirttimaa Oy | Administrative & support | 2023 |
| PR-Tavaratalo-avoin yhtiö | Wholesale & retail | 1989 |
| PVA Palvelu Oy | Construction | 2008 |
| Peltisepänliike L Vikki Oy | Construction | 1985 |
| Penttalan perhekulttuuripalvelu Ky | Health & social care | 2005 |
| Perttu Suonsyrjä Oy | Information & communication | 2020 |
| Pinson Oy | Professional & scientific | 1993 |
| Pomocon Kiinteistöpalvelut Oy | Administrative & support | 2020 |
| ProShop Bro's Oy | Wholesale & retail | 2021 |
| ProTime Oy Tili ja Media | Professional & scientific | 2007 |
| Process Piping Service Oy | Manufacturing | 2020 |
| Profile Art - Hiusmuotoilua Oy | Other services | 2013 |
| Pub Imperium Oy | Hospitality | 2022 |
| Puun Kuljetus Oy | Agriculture & fishing | 1976 |
| Rakentajan Koti OY | Wholesale & retail | 2012 |
| RakAsYhtiöt Oy | Professional & scientific | 2025 |
| Rasmus Höglund Oy | Health & social care | 2025 |
| Real Estate Kings Oy | Real estate | 2021 |
| Reikko Oy | Manufacturing | 1982 |
| Reponen Oy | Manufacturing | 1986 |
| Rilatex Ky | Manufacturing | 1986 |
| Risutec Oy | Manufacturing | 2004 |
| RoseCon Acoustic Oy | Construction | 2022 |
| Roviko Oy | Real estate | 2021 |
| Ruokapaja-Ahjo Oy | Hospitality | 2008 |
| Ruoppaus P. Suominen Oy | Construction | 1979 |
| Ruskilan Maansiirto Oy | Construction | 2007 |
| Rusthollin Ratsastuskoulu Oy | Education | 2015 |
| SPS-Metalli Oy | Manufacturing | 2012 |
| SaSuCo Oy | Manufacturing | 2016 |
| Saint-Wear Oy | Manufacturing | 1987 |
| Salomonkallio Oy | Arts & recreation | 1989 |
| San-Meta Oy | Manufacturing | 2006 |
| Sata-Öljy Oy | Manufacturing | 1997 |
| Satakunnan Bioenergia Oy | Manufacturing | 2006 |
| Satakunnan Kärry ja Ajoneuvoasennus Oy | Other services | 2019 |
| Satakunnan Talousohjaus Oy | Professional & scientific | 1995 |
| Satapro osk | Administrative & support | 2010 |
| Satatarkastus Oy | Professional & scientific | 1997 |
| Setolan Kuljetus Oy | Transport & logistics | 1978 |
| Sevifield Oy | Real estate | 2009 |