| Natureeline Limited | Wholesale & retail | 2019 |
| Navigate Business Recovery Limited | Professional & scientific | 2017 |
| NBM Developments Ltd | Construction | 2008 |
| NDJ Denton Services Ltd | Transport & logistics | 2022 |
| NE Commerical MRF Ltd | Water & waste | 2025 |
| Negativland Ltd | Information & communication | 2024 |
| Neil Harrison Commissioning Services Limited | Information & communication | 2007 |
| NEO Realty Ltd | Hospitality | 2023 |
| Neoskill Ltd. | Information & communication | 1997 |
| Nest Constructions &Designs Ltd | Hospitality | 2022 |
| Nestcrafters Limited | Real estate | 2025 |
| Nestlodge Limited | Real estate | 2009 |
| Never TOO Late to Study UK Limited | Education | 2024 |
| New Aggregate Limited | Administrative & support | 2020 |
| New Inn Fownhope Ltd | Real estate | 2026 |
| Newfoundland Diagnostics Ltd | Wholesale & retail | 2020 |
| Nexgen Apps Limited | Information & communication | 2008 |
| Next Level Sales Solutions Ltd | Professional & scientific | 2026 |
| Nextgen Information Technologies Limited | Information & communication | 2020 |
| Nextgn Limited | Information & communication | 2013 |
| Nexu Capital Limited | Real estate | 2021 |
| Nigel Dickinson Aviation Ltd | Professional & scientific | 2022 |
| Nimbyx Limited | Information & communication | 2026 |
| Nittany Management Limited | Construction | 2005 |
| NJF Entertainment Limited | Professional & scientific | 2010 |
| Nlir Ltd | Administrative & support | 2025 |
| NMA Cube Ltd | Real estate | 2024 |
| Nmediasystems Ltd | Information & communication | 2010 |
| NO 67 Limited | Real estate | 2010 |
| NO 7 Nails & Toes Ltd | Other services | 2021 |
| Norman Humphrey Associates Limited | Information & communication | 2008 |
| Norred Consultancy Ltd | Professional & scientific | 2018 |
| Nort Studio Creative Ltd | Arts & recreation | 2020 |
| Northamptonshire Hotel Limited | Hospitality | 1996 |
| Northcot Properties Limited | Construction | 2017 |
| Northern Accomodation Providers Limited | Real estate | 1999 |
| Northgate (Warwick) Developments Limited | Construction | 2013 |
| Notebond Limited | Households | 2006 |
| Nourishu Limited | Wholesale & retail | 2023 |
| Nova Essentials Ltd | Wholesale & retail | 2024 |
| November House Limited | Extraterritorial | 2012 |
| NPD Enterprises Ltd | Administrative & support | 2007 |
| NPI Engineering Services Limited | Professional & scientific | 2020 |
| NRS Engineering & Consultancy Limited | Professional & scientific | 2023 |
| Nsbc Chalfont Limited | Professional & scientific | 2015 |
| Nssr Limited | Real estate | 2020 |
| NTK Health Ltd | Health & social care | 2024 |
| NTT Consultancy Limited | Professional & scientific | 2021 |
| Nuaa Collective Ltd | Health & social care | 2026 |
| Nugget Finance Ltd | Professional & scientific | 2019 |
| Number Four Stow Limited | Hospitality | 2017 |
| Numini Ventures Ltd | Wholesale & retail | 2025 |
| Nvsrk Properties Limited | Real estate | 2020 |
| Oasis Accounting Ltd | Professional & scientific | 2020 |
| Oasis Sports Ltd | Education | 2021 |
| Ocean Watch (2006) Limited | Households | 2006 |
| Octanet Solutions Ltd | Information & communication | 2019 |
| Odyssey Productions Limited | Manufacturing | 2021 |
| Offgrid Digital Ltd | Information & communication | 2025 |
| Offspring Installations Limited | Administrative & support | 2013 |
| OH Mixology Ltd | Wholesale & retail | 2024 |
| Ohura Properties Limited | Real estate | 2024 |
| Ojas Associates Limited | Information & communication | 2017 |
| OJS Electrics Ltd | Construction | 2025 |
| Ojyra Ltd | Information & communication | 2025 |
| Okappy Ltd. | Information & communication | 2015 |
| Okarla Limited | Wholesale & retail | 2024 |
| Old Amersham GIN Ltd | Wholesale & retail | 2016 |
| Old Town Jewellers Limited | Other services | 2017 |
| Olea Pain Clinic Ltd | Health & social care | 2017 |
| Olifel Limited | Professional & scientific | 2013 |
| Oliver Charles Garden Design&Build Ltd | Construction | 2026 |
| Olly's Barbers Ltd | Other services | 2020 |
| Olympia Recruitment Services Limited | Administrative & support | 2025 |
| Omkar Itech Ltd | Information & communication | 2020 |
| Omnia IT Services Limited | Information & communication | 2025 |
| Omniluden Ltd | Administrative & support | 2016 |
| Omsy Ltd | Education | 2019 |
| ON Nest Limited | Households | 2025 |
| Ondal Limited | Professional & scientific | 2025 |
| One Two Film Limited | Manufacturing | 2022 |
| One Vision Investments Limited | Real estate | 2014 |
| One Vision Professional Eyecare Limited | Wholesale & retail | 2014 |
| Onesixtwofour Consulting Ltd | Administrative & support | 2024 |
| Online Lessons Ltd | Education | 2020 |
| Opine Projects Limited | Professional & scientific | 2024 |
| Optax Limited | Information & communication | 2021 |
| Orca and BEE Ltd | Wholesale & retail | 2021 |
| Otium Services and Facilities Limited | Administrative & support | 2014 |
| Otterdene Property Ltd | Real estate | 2021 |
| Outlaw Supplies Ltd | Information & communication | 2019 |
| Oxford Chinese Academy Ltd | Administrative & support | 2019 |
| P & C Trading Ltd | Professional & scientific | 2017 |
| P a Cube Ltd | Information & communication | 2024 |
| P&P Trade Ltd | Wholesale & retail | 2025 |
| P.J. Donohoe Limited | Construction | 1978 |
| P.V. Contracts Limited | Professional & scientific | 2008 |
| Package Plant Services Ltd | Professional & scientific | 2021 |
| Palm Beach Enterprises Limited | Hospitality | 2016 |
| Pantheon Precious Metals Limited | Wholesale & retail | 2024 |