| Nano Developments Limited | Real estate | 1998 |
| Navabi Fabrications Ltd | Manufacturing | 2025 |
| Navabi Holdings Ltd | Financial services | 2021 |
| Navabi Limited | Construction | 2016 |
| NAW Holdings Ltd | Professional & scientific | 2020 |
| NBT Logistics Ltd | Transport & logistics | 2019 |
| NBT Transport Ltd | Transport & logistics | 2017 |
| NED Property Holdings Limited | Real estate | 2024 |
| Neeson Environmental Ltd | Construction | 2026 |
| Nest Architects (Cookstown) Ltd | Professional & scientific | 2016 |
| NEX GEN Agri Ltd | Financial services | 2025 |
| NI Auto Assist Legal Services Ltd | Professional & scientific | 2021 |
| NI Auto Assist Ltd | Other services | 2018 |
| NI Hydraulic Pumps Ltd | Manufacturing | 2013 |
| NI Oxygen+ Ltd | Health & social care | 2026 |
| NI Travel BUG Ltd | Administrative & support | 2018 |
| Niall a. Loughran Limited | Wholesale & retail | 2014 |
| Niamh Louise Foundation | Health & social care | 2020 |
| Nightowl Studio Ltd | Professional & scientific | 2024 |
| Nirvana Space Limited | Real estate | 2018 |
| Noble Herd Ltd | Wholesale & retail | 2024 |
| Norman Devlin Limited | Real estate | 2007 |
| North West Electrical Services LLP | | 2017 |
| Northern Ireland Rural Women's Network (Nirwn) | Information & communication | 2006 |
| Northern View Caravans Holdings Limited | Extraterritorial | 2013 |
| Northern View Holiday Homes Ltd | Real estate | 2013 |
| Northern View Leisure Limited | Hospitality | 2011 |
| Novi Electric Ltd | Manufacturing | 2022 |
| Nucommerce Ltd | Wholesale & retail | 2018 |
| Nude Food Ltd | Manufacturing | 2018 |
| Numar Ltd | Wholesale & retail | 2021 |
| Nutrigenx Ltd | Wholesale & retail | 2024 |
| Nuts 'N' Bolts Ltd | Wholesale & retail | 2017 |
| Nuvant Limited | Financial services | 2026 |
| Nxt-Car Ltd | Wholesale & retail | 2024 |
| O R Plastering Ltd | Construction | 2018 |
| O'Gara Construction Services (NI) Ltd | Construction | 2021 |
| O'Gara Joinery Ltd | Construction | 2014 |
| O'Hara Homes & Lettings Ltd | Real estate | 2024 |
| O4O Cookstown Ltd | Hospitality | 2004 |
| Oak Heights Company Limited | Extraterritorial | 2016 |
| Oasis Tax Solutions Ltd | Professional & scientific | 2025 |
| Oddium Ltd | Wholesale & retail | 2023 |
| Ohle Investments Ltd | Real estate | 2023 |
| Okpe Holdings Ltd | Financial services | 2025 |
| Old Coach Management Company Limited | Administrative & support | 2014 |
| Old Loughry Heritage Group | Education | 2013 |
| Oliver Corey Garages Ltd | Wholesale & retail | 2006 |
| Ollo Designs Ltd | Professional & scientific | 2025 |
| Olympia Gym Cookstown Ltd | Arts & recreation | 2024 |
| OMC Site Management Limited | Construction | 2020 |
| OMR Investments Ltd | Wholesale & retail | 2017 |
| Onac Properties Ltd | Real estate | 2025 |
| Onae Ltd | Other services | 2026 |
| Onwards Investments Ltd | Financial services | 2022 |
| Opera Developments Limited | Construction | 2002 |
| Oriental Buffet Ltd | Hospitality | 2018 |
| ORIGIN7 Digital Ltd | Construction | 2022 |
| Ornyx Ltd | Health & social care | 2023 |
| Orthotics International Ltd | Health & social care | 2015 |
| Oscar TV Limited | Information & communication | 2020 |
| Outbound X Limited | Professional & scientific | 2025 |
| Outfield Ltd | Wholesale & retail | 2019 |
| O’Hare Group Ltd | Construction | 2025 |
| P & J Garages Ltd | Wholesale & retail | 2021 |
| P and N 1 Limited | Real estate | 2020 |
| P and N 2 Limited | Real estate | 2020 |
| P and N 3 Limited | Real estate | 2020 |
| P Devlin Joinery Limited | Construction | 2015 |
| P O'Neill & Sons Ltd | Transport & logistics | 2003 |
| P Quinn Ltd | Construction | 2024 |
| P. Casey Engineering Limited | Financial services | 2012 |
| P.G. Solutions (NI) Ltd | Information & communication | 2003 |
| PA NI Properties Ltd | Real estate | 2024 |
| PAD (N.I.) Ltd | Construction | 2010 |
| Padart Ltd | Professional & scientific | 2021 |
| Pammer Holdings Limited | Wholesale & retail | 2010 |
| Panache Jewellery Displays Ltd | Wholesale & retail | 2006 |
| Pandara's Box Ltd | Information & communication | 2013 |
| Papeo Holdings Ltd | Financial services | 2025 |
| Paragon Digital Media Limited | Information & communication | 2023 |
| Passion Hair Ltd | Other services | 2017 |
| Patmond Energy Limited | Transport & logistics | 1996 |
| Patrick Mcoscar Ltd | Construction | 2013 |
| Patrick Quinn (NI) Limited | Agriculture & fishing | 2010 |
| Paud's Taxi Ltd | Transport & logistics | 2018 |
| Paul Campbell Properties Limited | Real estate | 1996 |
| Paula Maynes & Co Ltd | Professional & scientific | 2019 |
| PBK Developments Ltd | Construction | 2019 |
| PE Controls Ltd | Construction | 2019 |
| PE Healthcare (N.I.) Limited | Wholesale & retail | 2017 |
| Peerless Homes Ltd | Construction | 2020 |
| Pennie Investments Ltd | Financial services | 2016 |
| Performance Solutions Cookstown Ltd | Arts & recreation | 2015 |
| Pete Slevin Fitness Ltd | Arts & recreation | 2022 |
| Petrotech Environmental Ltd | Water & waste | 2011 |
| Philip Allen Ltd | Wholesale & retail | 2024 |
| Philip Barbour Associates Ltd | Professional & scientific | 2014 |
| Philip Patrick Interiors Limited | Construction | 2025 |
| PK Poultry Ltd | Agriculture & fishing | 2014 |