| Orada Construction Limited | Construction | 2024 |
| Orbital Flight Support Limited | Transport & logistics | 2019 |
| Origin Genetics Ltd | Agriculture & fishing | 2020 |
| Orpen Developments Limited | Administrative & support | 2004 |
| Orraview Construction Ltd | Construction | 2016 |
| Orwell Land Limited | Real estate | 2018 |
| Orwell Land Three Limited | Real estate | 2018 |
| Orwell Land Two Limited | Real estate | 2018 |
| Oskars Carparts Limited | Wholesale & retail | 2026 |
| Ottimo Coffee Roasters Limited | Manufacturing | 2020 |
| Ovalbridge Developments Ltd | Construction | 2014 |
| Ovalbridge Limited | Construction | 2003 |
| Owen Dickey Ltd | Real estate | 2026 |
| Owens Capital and Real Estate Limited | Real estate | 2026 |
| Oxley Square Holdings Limited | Professional & scientific | 2016 |
| Ozzy Productions Concept Ltd | Wholesale & retail | 2025 |
| P and S. G Ltd | Hospitality | 2005 |
| P M Electrics (NI) Ltd | Construction | 2013 |
| P Mcilroy Excavations & Utilities Ltd | Construction | 2024 |
| P Mcmullan Consultancy Limited | Construction | 2014 |
| P Mooney Decorators Ltd | Construction | 2008 |
| P Reid Investments Ltd | Real estate | 2021 |
| Pack-It (NI) Ltd | Wholesale & retail | 2003 |
| Packsy Ltd | Wholesale & retail | 2025 |
| Paddy Compare Limited | Financial services | 2012 |
| Panem Holdings Ltd | Financial services | 2023 |
| Park Design Associates Limited | Professional & scientific | 2016 |
| Park Mckillop & Co | Professional & scientific | 2003 |
| Park View Developments Limited | Households | 2020 |
| Parkmore Consulting Ltd | Information & communication | 2025 |
| Parkmore Management Ballymena Limited | Households | 2005 |
| Parkmore Vets Limited | Professional & scientific | 2015 |
| Pass Door Systems Ltd | Administrative & support | 2017 |
| Patton Holdings (NI) Ltd | Financial services | 2024 |
| Patton Property Ltd | Real estate | 2004 |
| Patton Training and Development Ltd | Administrative & support | 2016 |
| PBC Ceramics Limited | Wholesale & retail | 2006 |
| PCD Contracts Limited | Construction | 2016 |
| Pcml Electrical Ltd | Construction | 2017 |
| PD (N.I.) Groundworks Limited | Construction | 2022 |
| PDH Recycling Ltd | Water & waste | 2021 |
| Peak Performance Supplements Ltd | Health & social care | 2026 |
| Peak Shaving Ltd | Manufacturing | 2024 |
| PEB Trading Company Ltd | Wholesale & retail | 2022 |
| Peking House YU Ltd | Hospitality | 2018 |
| Pennybridge Property Limited | Real estate | 2010 |
| Pentagon Ballymena | Hospitality | 2005 |
| Penzel Trading Ltd | Construction | 2017 |
| Perfect Day Print Limited | Manufacturing | 2013 |
| Personnel & Training Services Ltd | Administrative & support | 2014 |
| Peter Dickson Electrical Ltd | Construction | 2021 |
| PFM Electrics Limited | Construction | 2017 |
| PH Harp Construction Ltd | Construction | 2025 |
| Philip Mcburney Racing Ltd | Arts & recreation | 2017 |
| Phillips Heating & Stoves Limited | Wholesale & retail | 2010 |
| Phoenix Properties (NI) Ltd | Real estate | 2017 |
| Pikehill Contracts Ltd | Professional & scientific | 2024 |
| Pikehill Properties Ltd | Real estate | 2024 |
| Pillpacplus Ltd | Wholesale & retail | 2014 |
| Planet OGO Media Ltd | Information & communication | 2018 |
| Platinum Assets NI Limited | Real estate | 2015 |
| Play and Display (N.I.) Ltd | Manufacturing | 2015 |
| PMC Developments Ltd | Construction | 2007 |
| PMC Property (Ballymena) Limited | Real estate | 2019 |
| Pmct Plumbing and Heating Ltd | Construction | 2021 |
| PMD Contractors Ltd | Construction | 2015 |
| PMG Projects Limited | Information & communication | 2013 |
| PML Electrical Contractor Ltd | Construction | 2025 |
| PMV Web Development Limited | Information & communication | 2022 |
| POD Squad Solutions Ltd | Administrative & support | 2026 |
| Poet's Walk Management Company Limited | Households | 2019 |
| Point Accounting (N.I.) Limited | Professional & scientific | 2005 |
| Pond Management Company Limited - the | Extraterritorial | 2005 |
| POR Contracts Limited | Construction | 2015 |
| POR Holdings Limited | Wholesale & retail | 2021 |
| POR Retail Limited | Wholesale & retail | 2021 |
| Portglenone Auto Services Ltd | Wholesale & retail | 2025 |
| Portglenone Enterprise Group Limited | Other services | 1997 |
| Portna Properties Limited | Real estate | 2022 |
| Portone Solutions Ltd | Professional & scientific | 2025 |
| Portstewart Convention | Health & social care | 2019 |
| Portsundays Ltd | Wholesale & retail | 2025 |
| Portview Developments Limited | Construction | 2018 |
| Potman Homes Ltd | Real estate | 2021 |
| Potter Finnegan Limited | Professional & scientific | 2015 |
| Power Sports Distribution Limited | Manufacturing | 2004 |
| Powercut Clothing (UK) Limited | Wholesale & retail | 2024 |
| PPP Group Holding Company Limited | Water & waste | 2017 |
| PPP Group Tyre Recycling Limited | Water & waste | 2018 |
| PPP Salvage Limited | Water & waste | 2017 |
| PPP TDF Ltd | Water & waste | 2017 |
| Precious Moments Boutique Limited | Wholesale & retail | 2014 |
| Precision Electrical Contracts Ltd | Construction | 2019 |
| Prestige Diagnostics U.K. Ltd | Wholesale & retail | 2012 |
| Prestige NI Home Solutions Limited | Construction | 2025 |
| PRH & Co Holdings Ltd | Construction | 2017 |
| PRH Plant and Vehicle Hire Ltd | Administrative & support | 2020 |
| Pro-Form Nutrition Limited | Manufacturing | 2016 |
| Product Quality & Qualified Person Services Ltd | Professional & scientific | 2021 |
| Profab (N.I.) Limited | Manufacturing | 2025 |