| Naulei Ltd | Transport & logistics | 2019 |
| Nautequipe Marine Supplies Limited | Wholesale & retail | 1998 |
| Naviprofit Ltd | Administrative & support | 2019 |
| Nbcc Limited | Professional & scientific | 2013 |
| NCG DY Limited | Hospitality | 2025 |
| NDP Electrical Services Limited | Construction | 2004 |
| NDP Group Limited | Administrative & support | 2019 |
| Nebonzith Ltd | Hospitality | 2023 |
| Nechtanzy Ltd | Hospitality | 2023 |
| Needham Enterprises (Carpets) LLP | | 2011 |
| Needham Enterprises Limited | Wholesale & retail | 1980 |
| NEO Beauty Group Ltd | Wholesale & retail | 2022 |
| Neocrea Ltd | Financial services | 2025 |
| Nestclicks Limited | Construction | 2019 |
| NET Zero POD Limited | Extraterritorial | 2024 |
| Nether Kiddington Ltd | Health & social care | 2021 |
| Neurodiversity League Ltd | Manufacturing | 2026 |
| Neutherium Ltd | Administrative & support | 2024 |
| Neutravers Ltd | Administrative & support | 2024 |
| Neutriux Ltd | Administrative & support | 2024 |
| Nevermelt Digital Ltd | Information & communication | 2025 |
| Nevil Harrison Motor Repairs Limited | Wholesale & retail | 2011 |
| New Crown Bakery Limited | Manufacturing | 1964 |
| New Dawn Community Care Ltd | Health & social care | 2024 |
| New Leaf Construction Ltd | Construction | 2018 |
| New Lili Italia Ltd | Hospitality | 2026 |
| New Wave Bathrooms Limited | Wholesale & retail | 2005 |
| Newby Foundries Investment Casting Limited | Manufacturing | 1977 |
| Neweyz Dealz Ltd | Wholesale & retail | 2025 |
| Newgrange Training and Services Limited | Administrative & support | 2001 |
| Newlan Projects Limited | Construction | 2022 |
| Newnham Barns Management Company Limited | Professional & scientific | 2007 |
| Newsmarket (Midlands) Limited | Wholesale & retail | 2005 |
| Nextcloud Limited | Professional & scientific | 1929 |
| NFF Trading Services C.I.C. | Administrative & support | 2011 |
| NG Rooney Ltd | Administrative & support | 2021 |
| NG Utility Savings Ltd | Administrative & support | 2024 |
| Ngrm Limited | Professional & scientific | 2012 |
| Nibloyze Ltd | Hospitality | 2023 |
| Nicholls & Sons Painting & Decorating Ltd | Construction | 2025 |
| Nicieja Ltd | Transport & logistics | 2023 |
| Nick Millinchip Ltd | Professional & scientific | 2025 |
| Nick Richards Associates Ltd. | Professional & scientific | 2016 |
| Nicol Transmissions (UK) Limited | Wholesale & retail | 2004 |
| Nicson Training Limited | Education | 2024 |
| Nigel Porter Wealth Management Limited | Financial services | 2019 |
| Nineveh Ridge Care Farm | Health & social care | 2008 |
| NJ Lloyd Properties Limited | Real estate | 2022 |
| NJH Joinery Ltd | Manufacturing | 2025 |
| NO Mondays Ltd | Manufacturing | 2025 |
| Noah Bloomer and Sons Limited | Manufacturing | 2008 |
| Noah Bloomer Limited | Manufacturing | 1909 |
| Noblembr Ltd | Professional & scientific | 2025 |
| Nocturnal Consulting Ltd | Information & communication | 2024 |
| Noirefare Ltd | Administrative & support | 2024 |
| NOK Construction Ltd | Construction | 2024 |
| Nome Communications Limited | Professional & scientific | 2001 |
| Norbert Mielczarek Limited | Construction | 2020 |
| Nordic Cedar Ltd | Real estate | 2022 |
| Norgrove Developments Ltd | Construction | 2016 |
| Norgrove Properties Ltd | Real estate | 2015 |
| North Grimston Ltd | Administrative & support | 2021 |
| North Wootton Ltd | Transport & logistics | 2021 |
| Northbirch Consulting Limited | Information & communication | 2018 |
| Northcrews Ltd | Administrative & support | 2019 |
| Norwegian Wood Travel Limited | Administrative & support | 1998 |
| Nova-Ida Ltd | Construction | 2019 |
| NPM Business Group Limited | Professional & scientific | 2002 |
| NPM Transport Limited | Transport & logistics | 2005 |
| NRC Fencing Limited | Construction | 2004 |
| NRG Financial Consultancy Ltd | Professional & scientific | 2026 |
| Nspic Limited | Financial services | 2023 |
| Nspire Electrical Services Limited | Construction | 2011 |
| Nstolt Ltd | Health & social care | 2021 |
| NT Rigging Ltd | Information & communication | 2025 |
| Ntm-Gb Limited | Manufacturing | 2003 |
| Nukon UK Limited | Wholesale & retail | 2014 |
| Number One Payroll Limited | Professional & scientific | 2022 |
| Numbers Matter Limited | Professional & scientific | 2019 |
| Nuroad Limited | Hospitality | 2025 |
| Nutone Limited | Construction | 2025 |
| NV Nail Bar Limited | Other services | 2026 |
| Nylaviux Ltd | Administrative & support | 2024 |
| O.T.Motors Ltd | Wholesale & retail | 2024 |
| OA Group Holdings Limited | Manufacturing | 2020 |
| Oak and Opal Ltd | Other services | 2021 |
| Oak House Management (Kidderminster) Limited | Households | 2006 |
| Oak Street Industrial Park Management Limited | Real estate | 2011 |
| Oakbury Flat Management Limited | Households | 1990 |
| Oakfords Limited | Other services | 2002 |
| Oakley Wilkinson Bryan Limited | Professional & scientific | 2001 |
| Oakshield Fire Service Ltd | Construction | 2025 |
| Oakview (Ltd) Limited | Professional & scientific | 2021 |
| Oasis Blinds & Shutters Ltd | Manufacturing | 2015 |
| OB Performance Limited | Professional & scientific | 2017 |
| Obeliskzith Ltd | Administrative & support | 2024 |
| Obsequence Ltd | Administrative & support | 2023 |
| Ocean Events Limited | Manufacturing | 2014 |
| Ocelia Group Ltd | Professional & scientific | 2024 |
| Ocelia Growth Group Ltd | Financial services | 2024 |