| Helsingin Akvaariokeskus Ky | Wholesale & retail | 1998 |
| Helsingin Ammatti-Isännöinti Oy | Real estate | 2015 |
| Helsingin Art & Bau Oy | Construction | 1994 |
| Helsingin Arvohammas Oy | Health & social care | 2007 |
| Helsingin Arvomerkki Oy | Wholesale & retail | 2014 |
| Helsingin Asenurkka Oy | Wholesale & retail | 1995 |
| Helsingin Asiantuntijamaalaus Oy | Construction | 2008 |
| Helsingin Aspari Oy | Real estate | 1995 |
| Helsingin Asumisoikeus Oy | Real estate | 1992 |
| Helsingin Asuntokauppiaat LKV Oy | Real estate | 2016 |
| Helsingin Asuntokeskus Oy | Financial services | 2017 |
| Helsingin Asuntomarkkinat Oy | Real estate | 1981 |
| Helsingin Asuntosijoitus ja Vuokraus Oy | Real estate | 2026 |
| Helsingin Atomitie A-C Oy | Real estate | 2008 |
| Helsingin Atrium Oy LKV | Real estate | 2017 |
| Helsingin Autokuljetus Oy | Transport & logistics | 2018 |
| Helsingin Autokylmä Oy | Manufacturing | 2016 |
| Helsingin Automaalaamo Oy | Other services | 2004 |
| Helsingin Autopalvelu Oy | Other services | 2019 |
| Helsingin Avain-Palvelu Oy | Wholesale & retail | 1989 |
| Helsingin Bouncer-palvelut Oy | Other services | 1996 |
| Helsingin Charterpurjehdus Oy | Transport & logistics | 2018 |
| Helsingin Cherokee Oy | Other services | 1993 |
| Helsingin City Hair Oy | Other services | 2001 |
| Helsingin City-Kiveys Oy | Construction | 1998 |
| Helsingin Cityburger Oy | Hospitality | 1995 |
| Helsingin DSH Ky | Professional & scientific | 2007 |
| Helsingin Deb Oy | Wholesale & retail | 1992 |
| Helsingin Design Kehys Oy | Wholesale & retail | 1985 |
| Helsingin Diesel Oy | Other services | 1966 |
| Helsingin EJT Hifi Oy | Wholesale & retail | 2014 |
| Helsingin Edustustila Oy | Real estate | 2000 |
| Helsingin Ekonomitoimisto Ky | Professional & scientific | 2016 |
| Helsingin Energiaekspertit Oy | Professional & scientific | 1982 |
| Helsingin Energiakuljetukset Oy | Transport & logistics | 2010 |
| Helsingin Energiatunnelit Oy | Real estate | 2014 |
| Helsingin Erga Kontakti Oy | Professional & scientific | 1994 |
| Helsingin Erikoishöyläys Oy | Manufacturing | 1996 |
| Helsingin Erottajankadun Huippu Upper Holding Oy | Real estate | 2011 |
| Helsingin Etelä Oy | Real estate | 2012 |
| Helsingin Festivaaliorkesteri Ky | Arts & recreation | 2005 |
| Helsingin Food-Service Oy | Hospitality | 2005 |
| Helsingin Funktiotest Oy | Health & social care | 1982 |
| Helsingin Fysioterapia Ky | Health & social care | 1983 |
| Helsingin GB-Team Oy | Wholesale & retail | 1992 |
| Helsingin Golfmiehet Oy | Arts & recreation | 1980 |
| Helsingin Gourmetclub Oy | Hospitality | 2006 |
| Helsingin Grillikebab ja Autopesula Oy | Hospitality | 2025 |
| Helsingin Habita Oy | Real estate | 2002 |
| Helsingin Hake Oy | Education | 2020 |
| Helsingin Halliosake Oy | Real estate | 2020 |
| Helsingin Hammaslaboratorio Oy | Health & social care | 1983 |
| Helsingin Hammasproteesi Oy | Financial services | 1977 |
| Helsingin Hammaspyörä Oy | Manufacturing | 1991 |
| Helsingin Hammassairaala Oy | Health & social care | 1992 |
| Helsingin Harjateräs Oy | Construction | 2018 |
| Helsingin Hautaushelmi Oy | Other services | 2022 |
| Helsingin Herkkusuut Oy | Professional & scientific | 1990 |
| Helsingin Herkkutukku Oy | Wholesale & retail | 1989 |
| Helsingin Hieronta-Akatemia Oy | Education | 2010 |
| Helsingin Hifi Oy | Wholesale & retail | 1992 |
| Helsingin Hinausapu Oy | Wholesale & retail | 1989 |
| Helsingin Hissiteknikot Oy | Financial services | 1982 |
| Helsingin Hitsaus HH Oy | Manufacturing | 2014 |
| Helsingin Hiusyrittäjäpalvelut Oy | Administrative & support | 2014 |
| Helsingin Hormitekniikka Oy | Administrative & support | 1998 |
| Helsingin Huoneistocenter Oy | Real estate | 2001 |
| Helsingin Huoneistoremontointi Oy | Construction | 2003 |
| Helsingin Huoneistorinki Oy | Real estate | 2005 |
| Helsingin Hyötykaluste Oy | Wholesale & retail | 2010 |
| Helsingin IV-Huolto Oy | Construction | 2012 |
| Helsingin Idelia Osuuskunta | Education | 1997 |
| Helsingin Ikkunanpesijät Oy | Administrative & support | 2025 |
| Helsingin Innomera Oy | Real estate | 1990 |
| Helsingin Innovaatiopalvelut Oy | Professional & scientific | 2011 |
| Helsingin Insinöörirakentajat Oy | Construction | 2023 |
| Helsingin Intercenter Oy | Wholesale & retail | 1996 |
| Helsingin Isännöinti-Center Oy | Administrative & support | 2011 |
| Helsingin Itsepuolustuskoulu Oy | Education | 2001 |
| Helsingin Jalkapallopubi Oy | Hospitality | 1997 |
| Helsingin Jazz-kissa Oy | Wholesale & retail | 2026 |
| Helsingin Jettihuolto Oy | Manufacturing | 2022 |
| Helsingin Jousiammuntahalli Oy | Wholesale & retail | 1989 |
| Helsingin Juhlatarvike Oy | Administrative & support | 2024 |
| Helsingin KH-Isännöinti Oy | Real estate | 1989 |
| Helsingin KTK Oy | Transport & logistics | 1953 |
| Helsingin Kaapeli Oy | Construction | 2003 |
| Helsingin Kalasatama HoldCo Ky | Real estate | 2020 |
| Helsingin Kalsaritehdas Ab | Manufacturing | 2021 |
| Helsingin Kamari Oy | Education | 1997 |
| Helsingin Kameragalleria Oy | Wholesale & retail | 1995 |
| Helsingin Kansallismedia Oy | Education | 1997 |
| Helsingin Kapteeninkatu 11 Huoneistot Oy | Real estate | 2020 |
| Helsingin Kartech Oy | Professional & scientific | 1991 |
| Helsingin Kasvisruokakauppa Oy | Wholesale & retail | 2015 |
| Helsingin Katto ja Kaide Oy | Construction | 1988 |
| Helsingin Kattotyö Oy | Construction | 2007 |
| Helsingin Kauppahansa Oy | Professional & scientific | 1997 |
| Helsingin Kauppapaikka Oy | Wholesale & retail | 2016 |
| Helsingin Kehonhallinta Oy | Education | 2013 |