| Naintaid Limited | Financial services | 2021 |
| Nant Ffrancon Roofing Ltd | Construction | 2025 |
| Nantporth C.I.C. | Hospitality | 2011 |
| Narra Care Services Limited | Administrative & support | 2023 |
| Nash Supplies Ltd | Wholesale & retail | 2017 |
| Nasoo Farms (NI) Ltd | Agriculture & fishing | 2018 |
| Natalie Reid Designs Ltd | Arts & recreation | 2015 |
| Naturalfile Limited | | 1996 |
| Navajo Talk Limited | Information & communication | 2009 |
| NCG Singles Ltd | Wholesale & retail | 2025 |
| NE Cleaning & Property Maintenance Ltd | Administrative & support | 2020 |
| Needwood House Limited | Extraterritorial | 1995 |
| Neep Pictures Ltd | Information & communication | 2019 |
| Neill & Company Wine Importers Ltd | Wholesale & retail | 2008 |
| Neill Collections Ltd | Real estate | 2025 |
| Neill Estate Agents LLP | | 2012 |
| Neill Wines Carrickfergus Limited | Wholesale & retail | 2016 |
| Neill Wines Limited | Wholesale & retail | 2008 |
| Neka Studio Limited | Professional & scientific | 2020 |
| Nervetest Ltd | Health & social care | 2023 |
| NET Zero Energy Services Ltd | Professional & scientific | 2024 |
| Net-Co Group Limited | Professional & scientific | 2022 |
| Network Cars NW Ltd | Transport & logistics | 2026 |
| Neurosomnics Ltd | Professional & scientific | 2026 |
| Never Ending Learning Limited | Information & communication | 2025 |
| New Bangor Grill Limited | Hospitality | 2024 |
| New Bangor Ltd | Hospitality | 2019 |
| New Bridewell 1 Limited | Construction | 2014 |
| New Bridewell 2 Limited | Construction | 2014 |
| New Bridewell Limited | Construction | 2014 |
| New Irish Arts Limited | Arts & recreation | 1998 |
| New Mart Road Limited | Construction | 2020 |
| New Wave Roleplay Ltd | Arts & recreation | 2025 |
| Newmark Developments Limited | Real estate | 2005 |
| Newry Juniors Limited | Health & social care | 2013 |
| News Speed Limited | Wholesale & retail | 1988 |
| Newtown Building Management Company Limited | Extraterritorial | 2008 |
| Newtownards Chronicle Limited | Information & communication | 1948 |
| Nexera Creatives Limited | Wholesale & retail | 2025 |
| Nexus Engineering (NW) Ltd | Construction | 2025 |
| Nexus Social Care Consultancy & Research Limited | Administrative & support | 2016 |
| Nexuz Software Ltd | Information & communication | 2026 |
| NI Abode Co Limited | Construction | 2025 |
| NI Boiler Spares Ltd | Wholesale & retail | 2024 |
| NI Breast Health Ltd | Health & social care | 2020 |
| NI Business Sales Ltd | Information & communication | 2025 |
| NI Drip Central Electronics & Appliances Limited | Wholesale & retail | 2023 |
| NI Drip Central Furniture Limited | Wholesale & retail | 2025 |
| NI Gwds Limited | Professional & scientific | 2024 |
| NI Hobby Limited | Wholesale & retail | 2025 |
| NI Solar House Ltd | Construction | 2019 |
| NI617492 Limited | | 2013 |
| Niall Miller Limited | Information & communication | 2018 |
| Nicelook Limited | Real estate | 2010 |
| Nichola Hawes Medical Ltd | Wholesale & retail | 2021 |
| Nicholas Design Limited | Information & communication | 2011 |
| Nicholas Graham Salon Limited | Other services | 2011 |
| Nickell & Richmond Ltd | Construction | 2015 |
| Nigel Anketell Ltd | Professional & scientific | 2015 |
| Nigel Raynor Cars Ltd | Administrative & support | 2025 |
| Night Shift Industries Ltd | Wholesale & retail | 2019 |
| Nightingale Psychology Services Limited | Health & social care | 2012 |
| Nightingale Ward Management Limited | Extraterritorial | 2003 |
| Nine Lives Games Ltd | Manufacturing | 2025 |
| Ning's Investment Limited | Real estate | 2024 |
| Nixon Accountancy Limited | Professional & scientific | 2023 |
| Njlrentals Ltd | Real estate | 2023 |
| NJM Accountancy Limited | Professional & scientific | 2015 |
| NJM LSA Ltd. | Real estate | 2018 |
| NJM Payroll Ltd | Professional & scientific | 2018 |
| Nltx Ltd | Administrative & support | 2019 |
| Nmah Ltd | Other services | 2019 |
| NMK Engineering Limited | Wholesale & retail | 2010 |
| Nmsm Ltd | Financial services | 2016 |
| NN Motors Ltd | Wholesale & retail | 2012 |
| Noctura Ltd | Wholesale & retail | 2013 |
| Node Lighting Limited | Professional & scientific | 2021 |
| Nolimitsnofear Ltd | Wholesale & retail | 2016 |
| Nomad I'R Enaid Ltd | Construction | 2021 |
| Norfolk & West Properties Limited | Real estate | 2016 |
| Norsk Maritime Heritage | Transport & logistics | 2024 |
| North Aromas Ltd | Wholesale & retail | 2024 |
| North Design Works Ltd | Professional & scientific | 2010 |
| North Down Boilers Limited | Construction | 2014 |
| North Down Car Sales Ltd | Wholesale & retail | 2026 |
| North Down Chiropractic Clinic Limited | Health & social care | 2012 |
| North Down Development Organisation Limited | Real estate | 1984 |
| North Down Developments Ltd | Construction | 2025 |
| North Down Electrics Limited | Construction | 2020 |
| North Down Health and Wellness Ltd | Wholesale & retail | 2018 |
| North Down Logs Ltd | Wholesale & retail | 2021 |
| North Down Motorcycles Ltd | Wholesale & retail | 2025 |
| North Down Motors Ltd | Wholesale & retail | 2015 |
| North Down PCC Limited | Health & social care | 2017 |
| North Down Private Ltd | Health & social care | 2025 |
| North Down Properties Ltd | Real estate | 2024 |
| North Down Security Installations Ltd | Construction | 2020 |
| North Down Support Solutions Ltd | Administrative & support | 2024 |
| North Down Trading Company Limited | Manufacturing | 2011 |
| North Down Transport Solutions Ltd | Transport & logistics | 2026 |