| Nick Griffin Holdings Limited | Financial services | 2022 |
| Nine Lives IT Limited | Information & communication | 2025 |
| Nisa Food & Wine Ltd | Wholesale & retail | 2022 |
| Nitova Limited | Real estate | 2025 |
| NJ Luxury Travel Ltd | Transport & logistics | 2025 |
| NM Sparrow Consulting Limited | Professional & scientific | 2023 |
| No-Ble Consultancy and Accounting Services Ltd | Professional & scientific | 2021 |
| Nordav Limited | Professional & scientific | 2024 |
| Norlund Limited | Professional & scientific | 2000 |
| Norman Rhead Limited | Extraterritorial | 2008 |
| Norris Technician Services Ltd | Wholesale & retail | 2025 |
| North Staffs. Irrigation Limited | Other services | 1998 |
| Northesk Street Management Limited | Other services | 2006 |
| Norton Lodge Care Homes Limited | Health & social care | 2015 |
| Notreme Engineering Developments Limited | Real estate | 1961 |
| Novagreen Renewables Ltd | Professional & scientific | 2025 |
| Novie Consulting Ltd | Information & communication | 2023 |
| NS ENG Design Ltd | Professional & scientific | 2011 |
| NSA Global Hospitality Ltd | Wholesale & retail | 2025 |
| Nstratagem Group Limited | Administrative & support | 2017 |
| Nursery Management Services Limited | Health & social care | 2025 |
| Nxtgen Multi Utilities Ltd | Construction | 2023 |
| O&A Poole Lettings Ltd | Real estate | 2025 |
| O&A Poole Ltd | Health & social care | 2021 |
| O'Connor & Associates Limited | Professional & scientific | 2012 |
| Oak Tree Farm Rural Project Limited | Agriculture & fishing | 2010 |
| Oasis Parque Limited | Professional & scientific | 2006 |
| Oatcakes & Milkshakes Ltd | Hospitality | 2015 |
| OBM Perspective Ltd | Professional & scientific | 2020 |
| Octobus Ltd | Professional & scientific | 2018 |
| ODL Packaging Limited | Wholesale & retail | 2016 |
| Olive Design & Media Limited | Information & communication | 2007 |
| Olivia ANN Aesthetics (2025) Ltd | Health & social care | 2025 |
| Olivia ANN Aesthetics Academy Ltd | Education | 2026 |
| Ologic (UK) Limited | Information & communication | 2006 |
| Ologic Limited | Other services | 2000 |
| ON the Edge Limited | Manufacturing | 2021 |
| Online Track Limited | Information & communication | 2018 |
| OOH LA LA Blow DRY Bar Ltd | Other services | 2023 |
| OPS Property Management Limited | Households | 2025 |
| Opti-Weld Limited | Manufacturing | 2018 |
| Optimus Commissioning Services Ltd | Professional & scientific | 2021 |
| Optionanalysis Ltd | Professional & scientific | 2003 |
| Orange Cat Marketing Limited | Professional & scientific | 2020 |
| Orbel Agriculture Limited | Agriculture & fishing | 2021 |
| Orbel Asset Management Ltd | Real estate | 2020 |
| Orbel Investments Ltd | Real estate | 2020 |
| Orbital GAS (Process and Instrumentation) Limited | Manufacturing | 1993 |
| Orbus Insight Limited | Information & communication | 2017 |
| Orchid and Oak Ltd | Education | 2025 |
| Orkcollectables Ltd | Wholesale & retail | 2025 |
| Orme Midlands Ltd | Construction | 2003 |
| ORR Training Holdings Ltd | Financial services | 2026 |
| OSS Enviro (Global) Limited | Public administration | 2022 |
| Otterly Ridiculous Ltd | Professional & scientific | 2026 |
| Oulton Croft Property Management Limited | Households | 2018 |
| Oulton Road (Stone) Management Limited | Households | 2007 |
| Ovilash (Staff) Ltd | Hospitality | 2022 |
| Ovilash Stone Limited | Hospitality | 2019 |
| Owlett-Jaton Limited | Extraterritorial | 1995 |
| PAD Development Limited | Construction | 2024 |
| PAG Accountancy Limited | Professional & scientific | 2014 |
| Panda Press Publishing Ltd | Information & communication | 2019 |
| Parcelomatic Ltd | Transport & logistics | 2023 |
| Parcelomatic Newcastle Ltd | Transport & logistics | 2026 |
| Parlo Properties Limited | Hospitality | 2025 |
| Parogon HQ Ltd | Administrative & support | 2023 |
| Paul Reynolds Centre Limited | Real estate | 1973 |
| Paul Rushworth Limited | Professional & scientific | 2015 |
| PAV Joinery & Construction Ltd | Manufacturing | 2022 |
| Peach and Willow Ltd | Wholesale & retail | 2020 |
| Pear & Son's Ltd | Professional & scientific | 2019 |
| Pear Bars Limited | Construction | 2017 |
| Pearl Chemicals Holdings Limited | Extraterritorial | 2016 |
| Pearl Chemicals Limited | Wholesale & retail | 1996 |
| Pegasus Scaffolding (Midlands) Ltd | Construction | 2023 |
| Peligro Risk Management Ltd | Public administration | 2007 |
| Perceptive Instruments Limited | Information & communication | 1990 |
| Pete Mason Consulting Limited | Professional & scientific | 2018 |
| Phil Shelton Geotechnical Consultancy Limited | Professional & scientific | 2019 |
| Phoenix Works (Stoke on Trent) Ltd | Real estate | 2026 |
| Piccolos 14 Limited | Hospitality | 2019 |
| Picture News Limited | Education | 2016 |
| Pinewood Eco Properties Limited | Real estate | 2025 |
| Pink Sands Beauty Ltd | Wholesale & retail | 2022 |
| Pipik Limited | Real estate | 2018 |
| Pixeloop Limited | Extraterritorial | 2023 |
| Plando Ltd | Professional & scientific | 2007 |
| Planninglite Ltd | Education | 2023 |
| Plant & Co Limited | Professional & scientific | 2011 |
| Plant Business Services Limited | Professional & scientific | 2020 |
| Plant Group Investments Limited | Real estate | 2011 |
| Plantcare Foliage Display Specialists Limited | Administrative & support | 1998 |
| Planterra Ltd | Professional & scientific | 2018 |
| Pleasure of EVE Limited | Wholesale & retail | 2022 |
| PM Media Ltd | Information & communication | 2011 |
| PNG Management Ltd | Professional & scientific | 2023 |
| POI - FM Limited | Construction | 2018 |
| Polysource Holdings Group Limited | Manufacturing | 2000 |
| Porcelite Vitrified Hotelware Limited | Professional & scientific | 2006 |