| Nadia Holdings Ltd | Financial services | 2024 |
| Nadia Property Holdings Ltd | Real estate | 2024 |
| Nageem Electrical Ltd | Construction | 2025 |
| Namder Limited | Manufacturing | 2026 |
| Nationwide Recycling (IRL) Limited | Water & waste | 2014 |
| Natural Waste Management Limited | Agriculture & fishing | 2008 |
| Nature's Dawn Ltd | Wholesale & retail | 2019 |
| Nautical Ship Chandlers Limited | Wholesale & retail | 2020 |
| Navan at Armagh | Arts & recreation | 1989 |
| Navan at Armagh Management Limited | Arts & recreation | 1990 |
| Navan Fort Consulting Ltd | Administrative & support | 2006 |
| Navan Fort Transport Ltd | Transport & logistics | 2013 |
| Naíscoil NA Caille CIC | Education | 2017 |
| Nbfcs Ltd | Professional & scientific | 2022 |
| NBQ Ltd | Administrative & support | 2006 |
| NBQ Solutions Limited | Administrative & support | 2014 |
| NDD Investments Limited | Financial services | 2020 |
| NDJ Investments Limited | Financial services | 2019 |
| NE Power Solutions Ltd | Construction | 2023 |
| Needini Ltd | Wholesale & retail | 2023 |
| Neil Mcmullan Properties Ltd | Real estate | 2025 |
| Neiland & Creane (UK) Ltd | Manufacturing | 2025 |
| Nesbitt Electrical Ltd | Construction | 2019 |
| Nesbitt Engineering Limited | Construction | 2002 |
| Netstretch Limited | Information & communication | 2000 |
| Nevtex Innovations Ltd | Manufacturing | 2025 |
| New AGE Smoke Ltd | Wholesale & retail | 2014 |
| New Retro Vends LP | | 2024 |
| Newelec Solutions Ltd | Manufacturing | 2013 |
| Newline Ireland Ltd | Construction | 2025 |
| Newline Vehicle & Finance Limited | Wholesale & retail | 2008 |
| Newry Christmas Markets Ltd | Real estate | 2025 |
| Newry Pest Control Ltd | Administrative & support | 2025 |
| Nexaius Limited | Professional & scientific | 2025 |
| Next Level Surveys Ltd. | Professional & scientific | 2024 |
| NF Tyres & Alloys Ltd | Manufacturing | 2025 |
| NGD Services Ltd | Construction | 2019 |
| Ngnjoinery Limited | Construction | 2022 |
| NI App Solutions Ltd | Information & communication | 2014 |
| NI Homecare Ltd | Health & social care | 2023 |
| NI Planning Consultants Ltd | Professional & scientific | 2017 |
| Niall O'Donnell International Transport Ltd | Transport & logistics | 2025 |
| Nibblers Fast Food Limited | Hospitality | 2006 |
| Nifff Ltd | Agriculture & fishing | 2021 |
| Niosfearr Limited | Professional & scientific | 2026 |
| NJM Electricians Limited | Construction | 2023 |
| NKC Services Ltd | Financial services | 2015 |
| NMC Construction Limited | Construction | 2017 |
| Nmjhb Ltd | Real estate | 2026 |
| NNT Electrical Ltd | Construction | 2026 |
| Noel Conn & Company Limited | Professional & scientific | 2002 |
| Noel Mcelvanna Locum Limited | Health & social care | 2019 |
| Noli Armagh Ltd | Hospitality | 2026 |
| Nomos Partners Ltd. | Professional & scientific | 2015 |
| North Building Contracts Ltd | Construction | 2024 |
| North Coast Healthcare Limited | Wholesale & retail | 2022 |
| North East Home Buys Ltd | Real estate | 2025 |
| North Facades (Armagh) Limited | Construction | 2021 |
| Northern Truck and Trailer Ltd | Wholesale & retail | 2019 |
| Northrok Engineering Limited | Manufacturing | 2022 |
| Northrok Ltd | Manufacturing | 2022 |
| Northscope Digital Ltd | Professional & scientific | 2026 |
| Northstar Ambulance Ltd | Health & social care | 2025 |
| Nosredna Contracts Limited | Agriculture & fishing | 2020 |
| Nourish Foods Limited | Manufacturing | 2015 |
| NPL Storage and Distribution Ltd | Transport & logistics | 2025 |
| Ntll Limited | Real estate | 2023 |
| Nu-Build Property Limited | Construction | 2020 |
| Nubuild Brickwork Limited | Construction | 2014 |
| Nugent & Co. Limited | Construction | 2025 |
| Nugent Electrical Ltd | Construction | 2019 |
| Nugent Pigs Limited | Agriculture & fishing | 2012 |
| Nugent Plumbing Ltd | Construction | 2025 |
| Numoss Contracts Limited | Construction | 2011 |
| Nuuchem Diagnostics Limited | Health & social care | 2021 |
| O'Cuain Holdings Ltd | Financial services | 2023 |
| O'Neill Drain Services Ltd | Water & waste | 2025 |
| O'Neill Weddings & Events Ltd | Arts & recreation | 2023 |
| O'Reilly Agri Contracts Ltd | Agriculture & fishing | 2024 |
| O'Reilly Stonemasons Ltd | Construction | 2024 |
| O'Rourke Ireland Ltd | Wholesale & retail | 2012 |
| O.D Property Group Ltd | Real estate | 2025 |
| Oakhill Farm Quality Foods (NI) Limited | Manufacturing | 2024 |
| OCC Fitout Limited | Construction | 2020 |
| Ocho People Ltd | Information & communication | 2022 |
| ODS Automotives Limited | Manufacturing | 2013 |
| Office Space Facilities Limited | Administrative & support | 2023 |
| Ogle Street Investments Limited | Real estate | 2014 |
| Oh&M Limited | Manufacturing | 2022 |
| OIL Direct (NI) Limited | Wholesale & retail | 2013 |
| OJC Contracts Limited | Mining & quarrying | 2014 |
| OJC Enterprises Limited | Real estate | 2003 |
| OKE Holdings Ltd | Financial services | 2019 |
| Old Barn Catering Limited | Hospitality | 2019 |
| Oliver Food Stores Ltd | Wholesale & retail | 2016 |
| Omacproducts Ltd | Wholesale & retail | 2025 |
| Omnibus Events Ltd | Hospitality | 2015 |
| OMS Tools & Supplies Limited | Wholesale & retail | 2017 |
| Onebridge Saas Limited | Information & communication | 2025 |
| Optifi Ltd | Construction | 2021 |