| Lagan Energy Limited | Financial services | 2011 |
| Lagan Energy Trading Limited | Extraterritorial | 2024 |
| Lagan Environmental Limited | Professional & scientific | 2011 |
| Lagan Event Solutions Ltd | Administrative & support | 2024 |
| Lagan Facilities Management Limited | Extraterritorial | 2011 |
| Lagan Festival of Speech, Drama, Music and Art Ltd | Arts & recreation | 2010 |
| Lagan Financial Services Ltd | Professional & scientific | 2023 |
| Lagan Group (MGT) Limited | Financial services | 2010 |
| Lagan Group Limited | Professional & scientific | 2023 |
| Lagan Healthcare Investments Limited | Extraterritorial | 2011 |
| Lagan Homes (Ardnavalley) Ltd | Construction | 2014 |
| Lagan Homes (Beverley Garden Village) Ltd | Construction | 2015 |
| Lagan Homes (Blackwood) Limited | Construction | 2010 |
| Lagan Homes (Carryduff) Limited | Construction | 2013 |
| Lagan Homes (Charlestown Hall) Ltd | Construction | 2015 |
| Lagan Homes (Donaghadee Road) Ltd | Construction | 2023 |
| Lagan Homes (G.B.) Ltd. | Construction | 2010 |
| Lagan Homes (Hampton) Ltd | Construction | 2018 |
| Lagan Homes (Hillsborough) Ltd | Construction | 2023 |
| Lagan Homes (Lisburn) Ltd | Construction | 2014 |
| Lagan Homes (Magherahinch) Limited | Construction | 2013 |
| Lagan Homes (Millmount) Limited | Construction | 2009 |
| Lagan Homes (N.I.) Ltd | Construction | 2013 |
| Lagan Homes (Rathgael) Ltd | Construction | 2015 |
| Lagan Homes (Woodbrook) Limited | Construction | 2016 |
| Lagan Homes Antrim Limited | Construction | 2010 |
| Lagan Homes Group Ltd | Professional & scientific | 2014 |
| Lagan Homes Holdings Limited | Professional & scientific | 2025 |
| Lagan Homes Limited | Construction | 1983 |
| Lagan Homes Newtownards Limited | Construction | 2013 |
| Lagan Infrastructure Limited | Financial services | 2013 |
| Lagan Innovation Limited | Construction | 2020 |
| Lagan International (Holdings) Limited | Construction | 2005 |
| Lagan International Limited | Construction | 2000 |
| Lagan Investments (DEE) Ltd | Construction | 2018 |
| Lagan Investments (Duncrue) Ltd | Real estate | 2018 |
| Lagan Investments Holdings Ltd | Financial services | 2010 |
| Lagan Investments Ltd. | Financial services | 2015 |
| Lagan Legacy | Arts & recreation | 2002 |
| Lagan Management Limited | Professional & scientific | 2012 |
| Lagan Marine Training & Recruitment Ltd | Professional & scientific | 2019 |
| Lagan Meica Limited | Water & waste | 1996 |
| Lagan Operations & Maintenance Limited | Construction | 2001 |
| Lagan Paving Limited | Extraterritorial | 2011 |
| Lagan Piling Limited | Professional & scientific | 2011 |
| Lagan Project Management Limited | Extraterritorial | 2011 |
| Lagan Projects Investments Limited | Financial services | 2004 |
| Lagan Projects Limited | Professional & scientific | 2011 |
| Lagan Projects Maintenance Limited | Professional & scientific | 2011 |
| Lagan Property Investments Holdings Ltd | Financial services | 2010 |
| Lagan Property Investments Ltd | Real estate | 2019 |
| Lagan Remediation Limited | Extraterritorial | 2021 |
| Lagan Renewables Limited | Professional & scientific | 2011 |
| Lagan Ribs Ltd | Manufacturing | 2017 |
| Lagan Salt Limited | Extraterritorial | 2011 |
| Lagan Services Limited | Professional & scientific | 2001 |
| Lagan Smart Mobility Limited | Construction | 2020 |
| Lagan Software Solutions Limited | Information & communication | 2015 |
| Lagan Specialist Infrastructure Group Limited | Financial services | 2022 |
| Lagan Specialist Infrastructure Holdings Limited | Financial services | 2026 |
| Lagan Specialist International Limited | Construction | 2026 |
| Lagan Specialist Utilities & Maintenance Group Limited | Construction | 2013 |
| Lagan Specialist Utilities Limited | Construction | 1989 |
| Lagan Technical Services Limited | Construction | 2011 |
| Lagan Traffic Management Ltd | Construction | 2015 |
| Lagan Traffic Solutions Ltd | Construction | 2015 |
| Lagan Travel Ltd | Transport & logistics | 2026 |
| Lagan Ulitilies Limited | Professional & scientific | 2011 |
| Lagan Valley Education Project Limited | Education | 1999 |
| Lagan Valley Properties Ltd | Real estate | 2014 |
| Lagan Valley Vets Ltd. | Professional & scientific | 2014 |
| Lagan Village Youth & Community Group | Other services | 2014 |
| Lagan Windfarm Investments Limited | Professional & scientific | 2011 |
| Lagan WM Limited | Financial services | 2018 |
| Lagan WM NO.2 Ltd | Financial services | 2020 |
| Laganbank East Ltd | Construction | 2015 |
| Laganbridge IT C.I.C. | Manufacturing | 2025 |
| Laganmore Food Products Limited | Wholesale & retail | 1994 |
| Laganside Construction Ltd | | 1997 |
| Laganvale Management NO. 3 Limited | Households | 1993 |
| Laganview Management Company Limited | Households | 1993 |
| Laganville Court Ltd | Households | 2012 |
| Laggan Properties Limited | Agriculture & fishing | 1995 |
| Lagmar Properties Limited | Administrative & support | 2005 |
| Lagmore (3) Apartments Management Company Limited | Real estate | 2015 |
| Lagmore Apartments Management Company Limited | Real estate | 2013 |
| Lagmore Community Forum | Health & social care | 2007 |
| Lagmore Developments Limited | Real estate | 1995 |
| Lagmore Enterprises Ltd | Professional & scientific | 2004 |
| Lagmore Property Limited | Wholesale & retail | 2021 |
| Lagmore Services Limited | Wholesale & retail | 1994 |
| Lagom Safety Ltd | Professional & scientific | 2022 |
| Lagpor Developments Limited | Construction | 2017 |
| LAI Leik Limited | Wholesale & retail | 2024 |
| Lailibin Ltd | Wholesale & retail | 2024 |
| Laird Grass Machinery Limited | Wholesale & retail | 1998 |
| Lairie Ltd | Manufacturing | 2022 |
| Lake & Air Events Limited | Information & communication | 2009 |
| Lake 22 Limited | Real estate | 1971 |
| Lake Forest (NI) Limited | Manufacturing | 2026 |