| ABT Markkinointi Oy | Wholesale & retail | 2025 |
| ASK-TALLI Ky | Agriculture & fishing | 2002 |
| Ahosen Taimisto Oy | Agriculture & fishing | 1984 |
| Aloha-Tietotalo OY | Wholesale & retail | 1991 |
| Anra Oy | Wholesale & retail | 1989 |
| Aptepa Oy | Professional & scientific | 1992 |
| Aristo Komponenten Oy | Manufacturing | 1992 |
| Autofixaus ja huolto Pekkala Oy | Other services | 2024 |
| Autohuolto T & M Reini Oy | Wholesale & retail | 1993 |
| Autosen urakointi Oy | Mining & quarrying | 1993 |
| Avoin Yhtiö tupla O | Professional & scientific | 2007 |
| Bellapipe Holding Oy | Financial services | 1994 |
| Bellapipe Oy | Manufacturing | 2024 |
| Beweldo Oy | Manufacturing | 2024 |
| Brooco Oy | Administrative & support | 2023 |
| DotHouse Oy | Wholesale & retail | 2014 |
| Eeva-keittiöt Ky | Construction | 2013 |
| Ekonomitoimisto Ilkka Västi Oy | Professional & scientific | 2023 |
| Eläinkuljetus Hakala Oy | Transport & logistics | 2014 |
| Epira Oy | Manufacturing | 2005 |
| Finn-Savotta Oy | Manufacturing | 2016 |
| Finn-Savotta Systems Oy | Manufacturing | 2013 |
| Firat kebab-pizzeria avoin yhtiö | Hospitality | 2015 |
| HTS Sähkö Oy | Construction | 2024 |
| Habitus Oy | Professional & scientific | 2010 |
| Hakala Forest Oy | Agriculture & fishing | 2012 |
| Hakalan Rahti Oy | Financial services | 2014 |
| Heavy Center Hirvaskangas Oy | Other services | 2018 |
| Heavy Partners Oy | Real estate | 2026 |
| Heavy-Trans Oy | Transport & logistics | 2008 |
| High view action Oy | Professional & scientific | 2025 |
| Hilyan Hill Oy | Financial services | 2020 |
| Hirsityö Heikkilä Oy | Construction | 2009 |
| Hokkanen & Poika Oy | Wholesale & retail | 2008 |
| Hokkasen Betonituote Oy | Manufacturing | 1980 |
| Honkarakenne Oyj | Manufacturing | 1970 |
| Hulin Puu Oy | Manufacturing | 2022 |
| Hulinkallio Oy | Manufacturing | 2019 |
| Huliswood Oy | Manufacturing | 1998 |
| Huoltokorjaamo Peltonen & Syrjälä Avoin Yhtiö | Manufacturing | 2006 |
| Huoltopalvelu J.Harju Oy | Manufacturing | 2022 |
| Höyläniemen Helmi Oy | Health & social care | 2026 |
| Iceblock Oy | Financial services | 2014 |
| Iiris Engineering Oy | Professional & scientific | 2019 |
| Ilomet Oy | Manufacturing | 2017 |
| Inventek Oy | Information & communication | 2001 |
| J. Kotilainen Ky | Wholesale & retail | 1996 |
| JRS Greentech Oy | Wholesale & retail | 2023 |
| Jalonen Agency ky | Administrative & support | 2014 |
| K-S Super Timber Oy | Manufacturing | 1994 |
| K-S Voiman Siirto Oy | Real estate | 2020 |
| Kardelux OY | Health & social care | 2024 |
| Karstulan Elementtikuljetus OY | Transport & logistics | 2014 |
| KNH-Tuote Oy | Manufacturing | 1983 |
| KR-Kiinteistöt Oy | Real estate | 2022 |
| Ka-Mu Oy | Manufacturing | 1982 |
| Karhus Oy | Administrative & support | 2018 |
| Karstula Areena Oy | Arts & recreation | 2010 |
| Karstula Invest Oy | Real estate | 2012 |
| Karstula Punttis Oy | Arts & recreation | 2012 |
| Karstula Viski osk | Manufacturing | 2003 |
| Karstulan Arkkuverhoomo Kotanen Ky | Manufacturing | 1989 |
| Karstulan Autokoulu Oy | Education | 1990 |
| Karstulan JAPA avoin yhtiö | Mining & quarrying | 2023 |
| Karstulan Kartsa Oy | Wholesale & retail | 1986 |
| Karstulan Kimara Oy | Wholesale & retail | 2020 |
| Karstulan Konditoria Körkkö & Co | Wholesale & retail | 1989 |
| Karstulan Kunnon Sali Oy | Arts & recreation | 2025 |
| Karstulan Laaturakennus Oy | Construction | 1997 |
| Karstulan Lämpöverkko Oy | Energy | 1999 |
| Karstulan Metsätyö KY | Agriculture & fishing | 2017 |
| Karstulan Painopalvelu Ky | Manufacturing | 1984 |
| Karstulan Pala-Aitta Ky | Wholesale & retail | 1973 |
| Karstulan Portti Oy | Real estate | 2014 |
| Karstulan Seudun Ravitsemuspalvelut KARSERA Oy | Hospitality | 2023 |
| Karstulan Sisustus Ky | Wholesale & retail | 1985 |
| Karstulan Tennis Oy | Arts & recreation | 1984 |
| Karstulan Vene Järvinen Ky | Manufacturing | 1978 |
| Karstulan Öljy- ja Autotarvike Oy | Wholesale & retail | 2000 |
| Kauppahuone Nurmela avoin yhtiö | Wholesale & retail | 2015 |
| Kehittämisyhtiö Karstulanseutu Oy | Professional & scientific | 1990 |
| Keski-Suomen Kyläsuutarit Oy | Other services | 2024 |
| Kiinnike Holding Oy | Financial services | 2025 |
| Kiinnikepaja Oy | Manufacturing | 1994 |
| Kiinteistö Oy KM Kiinteistöt | Real estate | 2018 |
| Kiinteistö Oy Karstulantie 5 | Real estate | 2004 |
| Kiinteistö Oy Steelroad | Real estate | 2015 |
| Kiinteistöosakeyhtiö Karstulan Auringonpimennys | Real estate | 2015 |
| Kiinteistöosakeyhtiö Karstulan JarTap Oy | Real estate | 2016 |
| Kiipa Marttinen Ky | Administrative & support | 1990 |
| Kipu Oy | Real estate | 1983 |
| Kone ja Kuljetus Kalm Oy | Transport & logistics | 2025 |
| Koneurakointi H. Mäenpuro Oy | Construction | 2007 |
| Koskimaja Oy | Real estate | 2015 |
| Kukka ja Valaisin Aladdin Ky | Wholesale & retail | 1984 |
| Kuljetus Lavu Oy | Transport & logistics | 2002 |
| Kuljetusliike Jorma Kemppainen Oy | Transport & logistics | 1998 |
| Kyy-Sähkö Oy | Real estate | 1986 |
| Kyyjärven Realisointi ja Tarvike Oy | Wholesale & retail | 2022 |
| L & M Sillanpää Oy | Administrative & support | 1995 |