| D G Mcclean Ltd | Construction | 2025 |
| D&C Mcelroy Ltd | Agriculture & fishing | 2025 |
| DA Renewables Limited | Energy | 2014 |
| Dale Kane Trailers Limited | Manufacturing | 2018 |
| Damhead Mews Management Company Limited | Households | 2020 |
| Dapani Group Ltd | Real estate | 2025 |
| DB Building & Joinery Ltd | Construction | 2020 |
| Dechomet Community Group Ltd | Other services | 2021 |
| Design by Manor House Ltd | Manufacturing | 2012 |
| Djee Limited | Professional & scientific | 2025 |
| DM Earthworks Ltd | Construction | 2022 |
| Dolmen Farm Limited | Agriculture & fishing | 2010 |
| Donard Clinic Limited | Professional & scientific | 2021 |
| Donard Estates Ltd | Real estate | 2021 |
| Double W2 Ltd | Real estate | 1987 |
| Down Hot TUB Hire Ltd | Administrative & support | 2020 |
| Downpatrick Property Holdings Ltd | Financial services | 2016 |
| Drumillen Management Limited | Professional & scientific | 2012 |
| Drumlin Grange Management Ltd | Households | 2004 |
| Drumman Hall Limited | Real estate | 2026 |
| Dundrinne Close Ltd | Real estate | 2018 |
| Dundrinne Developments Limited | Construction | 2026 |
| Dundrinne Properties Limited | Construction | 2026 |
| Dunlevy Contracts Limited | Construction | 2010 |
| E Lennon & SON Ltd | Wholesale & retail | 2013 |
| Echo Direct Construction Ltd | Construction | 2024 |
| Eco Roof Ltd | Construction | 2025 |
| Efrin Kurdish Barber Ltd | Other services | 2024 |
| Eight 5 Zero Group Limited | Financial services | 2023 |
| Electrical Testing Ireland Limited | Administrative & support | 2024 |
| Elite Plumbing, Heating & GAS Ltd | Construction | 2016 |
| Endeavor Project Solutions Ltd | Professional & scientific | 2025 |
| Endeavour 365 Limited | Information & communication | 2016 |
| Enni Properties Ltd | Real estate | 2022 |
| EOR Builders Ltd | Construction | 2007 |
| Epic Electrical Services Limited | Construction | 2020 |
| ESE Property Services Ltd | Construction | 2010 |
| Eveann Ltd | Extraterritorial | 2012 |
| F S Herron Limited | Manufacturing | 2009 |
| F.M. Contracts Co Ltd | Construction | 2009 |
| Fame Rider Global Ltd | Wholesale & retail | 2025 |
| Farrell Accountants Limited | Professional & scientific | 2015 |
| Faughanvale Limited | Hospitality | 2012 |
| Felix Mcevoy Limited | Wholesale & retail | 2008 |
| Flynn Energy Ltd | Energy | 2015 |
| Footfalls Walking Holidays UK Ltd | Administrative & support | 2015 |
| Forestpark Property Developments Limited | Real estate | 2017 |
| Fpdg Ltd | Professional & scientific | 2018 |
| Friends of Castlewellan Arboretum Ltd | Other services | 2026 |
| From Snout to Tail Limited | Hospitality | 2018 |
| G & M Property Limited | Professional & scientific | 2016 |
| G Force Contracts Ltd | Construction | 2015 |
| G Porter Haulage Limited | Transport & logistics | 2003 |
| G. & M. Lodge Caring Limited | Health & social care | 1986 |
| Gael Song Media Limited | Arts & recreation | 2026 |
| Gapogroup Ltd | Manufacturing | 2011 |
| Garden House Cafe Ltd | Hospitality | 2023 |
| Garran Limited | Professional & scientific | 1999 |
| Gems Bar Ltd | Hospitality | 2012 |
| Geodynamics N.I. Ltd | Professional & scientific | 2021 |
| Gewsm Holdings Ltd | Financial services | 2025 |
| Gewsm Ltd | Manufacturing | 2015 |
| Glengormley Chiropractic Clinic Limited | Health & social care | 2021 |
| Glenview Contracts Ltd | Construction | 2024 |
| Glór Uachtar Tire | Education | 2023 |
| GNP Groundworks Ltd | Construction | 2023 |
| Goark Developments Ltd | Construction | 2018 |
| Golf Sims Ireland Limited | Construction | 2025 |
| Grange Contract Services Limited | Construction | 2018 |
| Green Alchemy Limited | Professional & scientific | 2025 |
| Greenans Products Limited | Manufacturing | 2011 |
| Guttertec Ltd | Construction | 2014 |
| H&R Joinery Services (NI) Limited | Manufacturing | 2019 |
| Handlova Limited | Real estate | 2014 |
| Herron Contracts Limited | Construction | 2018 |
| Herron Holdings Limited | Financial services | 2017 |
| Hillside Homes (N.I.) Limited | Construction | 2021 |
| Hillview Plumbing Ltd | Construction | 2015 |
| Hillyard Hospitality Limited | Hospitality | 2018 |
| Holimun, Ltd | Hospitality | 2014 |
| Impact Youth Strategy Ltd | Professional & scientific | 2026 |
| Inne Property Holdings Ltd | Financial services | 2022 |
| Irvine Hoof Trimming Ltd | Agriculture & fishing | 2018 |
| J Maguire Upholstery Ltd | Manufacturing | 2007 |
| J N F Johnston Property Co Ltd | Households | 2026 |
| Jakon Limited | Real estate | 2023 |
| JAM Civils & Utilities Ltd | Construction | 2026 |
| Jarlath Branniff Surfacing Ltd | Construction | 2019 |
| JC Electrics (NI) Limited | Construction | 2012 |
| JEM Oils Ltd | Wholesale & retail | 2017 |
| JEM Property, Development & Design Limited | Construction | 2024 |
| Jewel Properties (N.I.) Limited | Real estate | 2025 |
| JMC Connect Ltd | Construction | 2022 |
| JMH Electric Ltd | Professional & scientific | 2026 |
| John Brannigan Ltd | Construction | 2012 |
| John Mccartan Limited | Construction | 2007 |
| Jr's of Castlewellan Ltd | Wholesale & retail | 2011 |
| Jr's Retail Ltd | Wholesale & retail | 2024 |
| JS Mechanical 2022 Ltd | Construction | 2022 |
| Katch UP Limited | Manufacturing | 2007 |