| Natan Services Ltd | Transport & logistics | 2019 |
| National Retrofit Hub Community Interest Company | Professional & scientific | 2025 |
| National Roof Training Group Limited | Other services | 2020 |
| Natural Accounts Ltd | Professional & scientific | 2024 |
| Nautilus Drive Residents Association Limited | Households | 2017 |
| NB Electrical South West Limited | Construction | 2015 |
| Neat Accounting Ltd | Professional & scientific | 2016 |
| Need Consulting Limited | Professional & scientific | 2016 |
| Negus Steel Limited | Construction | 2020 |
| Neil Simpson Limited | | 1986 |
| Nelson Road Management Company Limited | Households | 1994 |
| Netley Grange Resident Management Company Limited | Households | 2023 |
| Neuro Nook Limited | Arts & recreation | 2025 |
| Neurodelta Ltd | Professional & scientific | 2007 |
| Neutral Space Ltd | Health & social care | 2011 |
| Neville Lodge Management Limited | Households | 2001 |
| New GEN Access Ltd | Construction | 2025 |
| New Hire Recruitment Ltd | Administrative & support | 2025 |
| New Moon Counselling Ltd | Health & social care | 2025 |
| New Silhouette Limited | Other services | 1999 |
| New Tandoori Gate Ltd. | Hospitality | 2018 |
| Newshrubbery Management Limited | Real estate | 2008 |
| NGR Properties Limited | Administrative & support | 2007 |
| Nikolovi BG Ltd | Manufacturing | 2023 |
| Niktrade&Build Group Ltd | Construction | 2020 |
| Nile Holdings (UK) Limited | Professional & scientific | 2005 |
| Nimmienterprise Limited | Wholesale & retail | 2025 |
| NK Food PVT Ltd | Hospitality | 2025 |
| NKT Carpentry and Building Limited | Construction | 2024 |
| NL Autos (Bognor) Ltd | Wholesale & retail | 2019 |
| NL Properties (Bognor) Ltd | Real estate | 2020 |
| NLP Services Limited | Professional & scientific | 2009 |
| NO.2 Coleherne Road Limited | Households | 1973 |
| Noble Elevate Limited | Professional & scientific | 2026 |
| Noble Lashes UK Ltd | Information & communication | 2016 |
| Noho Group Ltd | Financial services | 2026 |
| Norby Tailoring Limited | Wholesale & retail | 2024 |
| Norfolk Close Residents Association Ltd | Households | 2012 |
| Norfolk Court Residents Association Limited | Households | 2007 |
| Norfolk Court RTM Company Ltd | Households | 2011 |
| Norfolk Stores (Wells) Ltd | Other services | 2026 |
| Norsen Limited | Administrative & support | 2025 |
| North Field Developments Sussex Ltd | Construction | 2017 |
| Northbank Windows Limited | Construction | 2020 |
| Nova Epos Ltd | Wholesale & retail | 2023 |
| Novadrine Limited | Information & communication | 2020 |
| Novaug Limited | Professional & scientific | 2014 |
| Novu Studio Limited | Other services | 2024 |
| NOW Found Ltd | Wholesale & retail | 2026 |
| NP Aviation Limited | Transport & logistics | 2013 |
| NPI Freeholds Limited | Real estate | 2023 |
| NPM Property Services Limited | Construction | 2007 |
| NR Scaffolding Ltd | Construction | 2022 |
| NRG Marketing (Southern) Limited | Professional & scientific | 2008 |
| Nscape Limited | Administrative & support | 2011 |
| NSX Advisory Limited | Administrative & support | 2025 |
| NTH Degree Ltd | Professional & scientific | 2021 |
| NTL Holdings Ltd | Professional & scientific | 2022 |
| Nuclear Skin Ltd | Manufacturing | 2025 |
| Nuleaf Grounds Maintenance Limited | Administrative & support | 2020 |
| Numbered Property Investments Ltd | Real estate | 2020 |
| Nuvera Training Studio Ltd | Education | 2026 |
| Nvoco Ltd | Education | 2025 |
| O.G Plumbing & Heating Limited | Construction | 2019 |
| Oakfield Land and Homes Ltd | Construction | 2023 |
| Oakfield Land Limited | Construction | 2023 |
| Oakham Court Limited | Real estate | 1985 |
| Oakland Care Limited | Extraterritorial | 2023 |
| Oakmoore Contractors Limited | Construction | 2007 |
| Oakmoore Plant Limited | Administrative & support | 2010 |
| Oakwood Bay Properties Ltd | Real estate | 2020 |
| Oasis at West Park Limited | Hospitality | 2020 |
| Oban Solutions Ltd | Information & communication | 2025 |
| Ocean Dog Ltd | Extraterritorial | 2021 |
| Ocean Point Ltd | Information & communication | 2011 |
| Oceanview Shutters & Blinds Ltd | Wholesale & retail | 2024 |
| Ocentric Limited | Construction | 2008 |
| Ockley Road Residents Management Company Limited | Households | 2017 |
| Octigma Ltd | Administrative & support | 2021 |
| Odyssey Investment Group Limited | Financial services | 2018 |
| Oehairdesign Ltd | Other services | 2024 |
| OFF Road Biking Limited | Health & social care | 2026 |
| Office Athlete Ltd | Wholesale & retail | 2021 |
| Office Solve Limited | Professional & scientific | 2021 |
| OG Beauty Ltd | Other services | 2025 |
| OJE Projects Ltd | Real estate | 2024 |
| Old Fings Ltd | Wholesale & retail | 2026 |
| Old MAN Studios Ltd | Information & communication | 2023 |
| Old Place Residents Association | Households | 1971 |
| Oldland Consulting Limited | Professional & scientific | 2014 |
| Oldland Ltd | Professional & scientific | 2003 |
| OM Defense Group Ltd | Professional & scientific | 2024 |
| Omar Elfetiky Tooth Fixer Ltd | Health & social care | 2025 |
| Omono Technologies Ltd | Information & communication | 2013 |
| ON the Go! Event's Crew Ltd | Construction | 2018 |
| Oncorner Ltd | Manufacturing | 2020 |
| One and Done Holdings Ltd | Real estate | 2018 |
| One College Street (Stratford) Limited | Real estate | 2018 |
| One Hampshire Avenue Management Company Limited | Households | 2009 |
| One Small Speck Limited | Information & communication | 2000 |