| My Food in France Ltd | Hospitality | 2022 |
| My Methodical Ltd | Wholesale & retail | 2020 |
| My Sahara Cosmetics Ltd | Wholesale & retail | 2025 |
| N&P Tyres Ltd | Wholesale & retail | 2012 |
| Naree NI Ltd | Wholesale & retail | 2016 |
| NAT Capital Finance Limited | Financial services | 2020 |
| Nationwide Vehicle Carriers Ltd | Transport & logistics | 2026 |
| NAZ (2019) Ltd | Hospitality | 2019 |
| NCS Finishing Limited | Manufacturing | 2016 |
| Neary Investments Ltd | Financial services | 2026 |
| Nenc Ltd | Transport & logistics | 2019 |
| NEO Tech Energy Limited | Professional & scientific | 2016 |
| Neurovalens Limited | Manufacturing | 2013 |
| Never Accept Just Average Ltd | Wholesale & retail | 2025 |
| New Manley Limited | Hospitality | 2017 |
| New Road Enterprises Limited | Real estate | 2021 |
| New Villa Limited | Hospitality | 2025 |
| New World Developments Limited | Manufacturing | 1995 |
| New York Nails (Ballymena) Limited | Other services | 2014 |
| Newgrove Farm Ltd | Agriculture & fishing | 2024 |
| Newland Projects Limited | Construction | 2015 |
| NI Dietetics Limited | Health & social care | 2010 |
| NI Equine Dental VET Ltd | Professional & scientific | 2023 |
| NI Fraud Forum Limited | Other services | 2022 |
| NI Hello Homes Ltd | Real estate | 2025 |
| NI Kingdom Connections | Other services | 2018 |
| NI Leaky Finders Ltd | Construction | 2020 |
| NI Lighthouse Hostel Ltd | Education | 2023 |
| NI Living Solutions Limited | Manufacturing | 2022 |
| NI Plumbing Services Ltd | Construction | 2020 |
| NI Premier GEL Ltd | Wholesale & retail | 2021 |
| NI Security Solutions Ltd | Administrative & support | 2023 |
| Nigel Whann Accident Repair Centre Limited | Wholesale & retail | 2006 |
| Nigel Wilkinson Painting & Decorating Limited | Construction | 2018 |
| Nimed Ltd | Professional & scientific | 2025 |
| Nirbc Ltd | Water & waste | 2007 |
| Nisit INT Ltd | Administrative & support | 2023 |
| Nkcmc Ltd | Information & communication | 2014 |
| Nkechinyere & Co African Store Limited | Wholesale & retail | 2026 |
| NKP Holdings (N.I.) Ltd | Financial services | 2024 |
| NMG Plant Hire Ltd | Administrative & support | 2023 |
| NMG Properties Ltd | Real estate | 2015 |
| Noel Kidd Plastering Ltd | Construction | 2021 |
| Norbay Limited | Wholesale & retail | 2000 |
| Norbev Limited | Manufacturing | 2000 |
| Norman Gordon & Sons Contracts Ltd | Construction | 2012 |
| Norman Nicholl Kitchen Installations Ltd | Construction | 2022 |
| North Antrim Dairy Farmers' Development Group Ltd | Agriculture & fishing | 1997 |
| North Coast Consultants Ltd | Public administration | 2023 |
| North Coast Events Ltd | Hospitality | 2020 |
| North Coast Grip Solutions Ltd | Information & communication | 2021 |
| North Energy Limited | Professional & scientific | 2020 |
| Northera Ltd | Extraterritorial | 2025 |
| Northern CHI Management Limited | Professional & scientific | 2012 |
| Northern Ireland Renewables Ltd | Real estate | 2003 |
| Northern Plastering Ltd | Construction | 2025 |
| Northern Theta Consult Limited | Professional & scientific | 2012 |
| Northgen Power Solutions (NI) Ltd | Wholesale & retail | 2003 |
| Northshore Group Ltd | Wholesale & retail | 2026 |
| Norton & Mcclure Limited | Wholesale & retail | 2023 |
| NOT Only Healthy Back Limited | Other services | 2022 |
| Nova Eire Models Limited | Arts & recreation | 2024 |
| Novo People Ltd | Administrative & support | 2026 |
| NPD Carthall Ltd | Extraterritorial | 2022 |
| Nrjb Holdings Limited | Financial services | 2024 |
| NSB Automotive Ltd | Wholesale & retail | 2014 |
| NSW Sales Ltd | Wholesale & retail | 2023 |
| NTC Vehicles Ltd | Professional & scientific | 2025 |
| Nude Coffee Ltd | Hospitality | 2024 |
| Nuklide Ltd | Extraterritorial | 2023 |
| Nulok Global UK Ltd | Wholesale & retail | 2018 |
| O B Spoke Services Ltd | Manufacturing | 2011 |
| O'Boyle Roofing Limited | Construction | 2013 |
| O'Connors Fuels | Wholesale & retail | 2014 |
| O'Kane Farms Limited | Agriculture & fishing | 2014 |
| O'Kane Property Holdings Limited | Professional & scientific | 2009 |
| O'Kane Property Limited | Real estate | 2009 |
| O'Neill Brothers Limited | Real estate | 2024 |
| O'Neill Supplies Limited | Wholesale & retail | 2020 |
| O'Rorke Farms Ltd | Energy | 2021 |
| Oakhill Interiors Ltd | Construction | 2019 |
| OB Industries Limited | Wholesale & retail | 2018 |
| OBR Contracts Ltd | Construction | 2023 |
| Occw Commerce Limited | Wholesale & retail | 2024 |
| Octagon Global Consulting Limited | Construction | 2023 |
| Odinclutch Ltd | Wholesale & retail | 2025 |
| OFF Road Motorcycling NI Ltd | Arts & recreation | 2025 |
| OK Retail Ltd | Wholesale & retail | 2016 |
| Old Antrim Mews Management Company Limited | Extraterritorial | 2011 |
| Old Green Carrie Limited | Hospitality | 2025 |
| Old Oak Distillery Ltd | Manufacturing | 2022 |
| Older Oak Irish Whiskey Ltd | Manufacturing | 2025 |
| Omco Holdings Ltd | Real estate | 2023 |
| One Four Four Holdings (N.I.) Ltd | Real estate | 2025 |
| Onephoton Holdings Limited | Financial services | 2024 |
| Onephoton Limited | Professional & scientific | 2010 |
| Onibuild Ltd | Construction | 2024 |
| Only Washrooms Limited | Construction | 2025 |
| Onus (NI) Limited | Other services | 2007 |
| Opticom Networks Ltd | Information & communication | 2024 |