| Niemen Associates Limited | Professional & scientific | 1997 |
| Nitec (UK) Limited | Professional & scientific | 1986 |
| Noman Saghir Surgery Limited | Health & social care | 2023 |
| Nora Norway UK Limited | Wholesale & retail | 2011 |
| Norfolk Incense & Candles Limited | Wholesale & retail | 2023 |
| Norris Management Consultancy Ltd | Professional & scientific | 2008 |
| North Leeds Tennis Services Ltd | Education | 2022 |
| Northeast HSE Consultancy Limited | Administrative & support | 2016 |
| Northern Waste Solutions Ltd | Water & waste | 2026 |
| Northfield Accounting Limited | Professional & scientific | 2000 |
| Noshinn Fast Food Ltd | Hospitality | 2023 |
| NOT Guilty (Sunbridge Wells) Ltd | Hospitality | 2022 |
| Nouco Limited | Wholesale & retail | 2020 |
| Nova Care Training Ltd | Public administration | 2022 |
| Nova Care Yorkshire Ltd | Health & social care | 2019 |
| Novilla Medical Ltd | Health & social care | 2022 |
| Novus Finance Ltd | Financial services | 2008 |
| Novus Holdings Limited | Financial services | 2003 |
| Novus Sealing Limited | Professional & scientific | 1977 |
| NR Restaurants Ltd | Hospitality | 2024 |
| NSJ Builders Merchants Ltd | Construction | 2016 |
| Nsme Properties Limited | Real estate | 2023 |
| Nsuwa Group Ltd | Manufacturing | 2026 |
| Nutralab Ltd | Professional & scientific | 2024 |
| Nvest Residential Ltd | Real estate | 2025 |
| Nxtgen Care Group Ltd | Health & social care | 2025 |
| O'Hara (Holdings) Ltd | Financial services | 2012 |
| O'Haras Ltd | Professional & scientific | 2009 |
| Oak and Pine by Design Limited | Manufacturing | 2016 |
| OAL Capital Limited | Financial services | 2026 |
| OBL Aggregates & Excavation Limited | Mining & quarrying | 2016 |
| OCM Design Ltd | Professional & scientific | 2013 |
| Octeye Group Ltd | Administrative & support | 2018 |
| Odes Consultancy Limited | Administrative & support | 2025 |
| OFF SET Workshop Ltd | Construction | 2016 |
| Ogden Otters Limited | Arts & recreation | 2014 |
| Ogden Scaffolding Solutions Ltd | Construction | 2026 |
| Ohadmin Ltd | Administrative & support | 2026 |
| OKO Sports Ltd | Education | 2025 |
| Old Hall Homes Limited | Real estate | 2024 |
| Oldnook Properties Ltd | Real estate | 2024 |
| Olive Catering (Leeds) Ltd | Hospitality | 2024 |
| Olive Grooves Limited | Arts & recreation | 2008 |
| Olivia Properties Limited | Real estate | 1992 |
| Omnia Group Holdings Limited | Construction | 2015 |
| ON DOT Logistics Ltd | Transport & logistics | 2025 |
| Ondraft Ltd | Information & communication | 2026 |
| One RSJ Ltd | Real estate | 2025 |
| One-Two Digital Limited | Professional & scientific | 2017 |
| Onehum Ltd | Professional & scientific | 2022 |
| Onyx International Trading Limited | Extraterritorial | 1986 |
| Open Aspect Property Consultants Limited | Real estate | 2006 |
| Optimal HR Services Limited | Professional & scientific | 2021 |
| Optimal Recruitment Solutions Limited | Construction | 2021 |
| Optimise by Recruitment Ltd | Administrative & support | 2021 |
| Orange Domestic Projects Limited | Construction | 2018 |
| Orberie Ltd | Wholesale & retail | 2021 |
| Orean Personal Care Limited | Manufacturing | 2008 |
| Ostrich Legal Limited | Professional & scientific | 2023 |
| OUR Little Home Farm Limited | Agriculture & fishing | 2025 |
| Ovotar Ltd | Information & communication | 2024 |
| Owen Electrical Contractors Ltd | Construction | 2015 |
| OWL Parts Ltd | Wholesale & retail | 2017 |
| Oxford Grocers Ltd | Wholesale & retail | 2021 |
| Oxford Speedway Ltd | Wholesale & retail | 2026 |
| Ozone Dining Services Limited | Hospitality | 2022 |
| P Boden & Sons Limited | Construction | 2013 |
| P H Heating Engineers Limited | Construction | 2009 |
| P Hatfield Limited | Wholesale & retail | 2012 |
| P J Webster Investments Ltd | Professional & scientific | 2017 |
| Page Property Holdings Limited | Real estate | 2009 |
| Page Property Maintenance Limited | Construction | 2004 |
| Paint Manufacturer Ltd | Manufacturing | 2026 |
| Painting Advisory Services Limited | Professional & scientific | 1988 |
| Paintoutlet Ltd | Manufacturing | 2024 |
| Paintovate Technologies Ltd | Manufacturing | 2024 |
| Pallet Solutions Direct Ltd | Manufacturing | 2024 |
| Palmer and Palmer Properties Ltd | Real estate | 2016 |
| Pama Investments Limited | Real estate | 2012 |
| Papyrus Flowers Limited | Wholesale & retail | 2021 |
| Paramount Property Holdings Limited | Real estate | 2018 |
| Pareto Revision Ltd | Health & social care | 2020 |
| Parts Emporium Holdings Limited | Financial services | 2025 |
| Parts Emporium Ltd | Wholesale & retail | 2011 |
| Pasha Construction Limited | Construction | 2022 |
| Passion Security Ltd | Administrative & support | 2022 |
| Paul Jones Surveying Limited | Professional & scientific | 2018 |
| Paul Rhodes Precision Engineering Limited | Manufacturing | 2001 |
| Payment Payroll Ltd | Administrative & support | 2025 |
| Payntr Brand Limited | Wholesale & retail | 2015 |
| Paytec Ltd | Professional & scientific | 2024 |
| PBS Construction (West Yorkshire) Limited | Construction | 2016 |
| Pcare Brands Limited | Professional & scientific | 2017 |
| PDW Leasing Limited | Administrative & support | 2008 |
| Peace Ballers CIC | Education | 2019 |
| Pear Tree Realty Limited | Real estate | 2024 |
| Pearson Property Group Ltd | Real estate | 2016 |
| Pecore Properties (Merseyside) Limited | Real estate | 2015 |
| Pegasus Global Partners Ltd | Financial services | 2021 |
| Penhallick Limited | Arts & recreation | 2023 |