| NO 9 Limited | Extraterritorial | 2024 |
| NO Brainer Ltd | Wholesale & retail | 2018 |
| NO Name International Limited | Wholesale & retail | 2020 |
| NO.6 Dental Limited | Health & social care | 2007 |
| Noble Clean Ltd | Administrative & support | 2024 |
| Nocarbon Ltd | Information & communication | 2024 |
| Nominated Holdings Group Limited | Professional & scientific | 2018 |
| Noonan Electrics Limited | Construction | 2024 |
| Noqis Ltd | Professional & scientific | 2021 |
| Nordicpeak Academy Ltd | Education | 2023 |
| Noreen Tehrani Associates Limited | Information & communication | 2003 |
| Norfolk GY Enterprise Ltd | Hospitality | 2025 |
| Norfolk Lodge Limited | Households | 1986 |
| Normac Oils Holdco Ltd | Financial services | 2026 |
| Nornetica Ltd | Information & communication | 2025 |
| North Country Walks Ltd. | Professional & scientific | 2001 |
| North East Drones Limited | Extraterritorial | 2019 |
| North Star Transition | Professional & scientific | 2020 |
| North Yorks Properties Ltd | Real estate | 2024 |
| North Yorkshire Flooring Ltd | Wholesale & retail | 2024 |
| North Yorkshire Property Services Ltd | Real estate | 2025 |
| Northbay Limited | Hospitality | 1994 |
| Northbeck House 206-210 Northgate LLP | | 2006 |
| Northbrook Construction Limited | Construction | 2005 |
| Northdale Consulting Limited | Information & communication | 2018 |
| Northern Game Farm Ltd | Agriculture & fishing | 2019 |
| Northern Light and Sound Limited | Professional & scientific | 1989 |
| Northern Pubs Limited | Hospitality | 2001 |
| Northern Records Limited | Extraterritorial | 2005 |
| Northern Trailer Sales Ltd | Wholesale & retail | 2023 |
| Northern Trauma Consulting Ltd | Education | 2026 |
| Northline Strategies Ltd | Professional & scientific | 2025 |
| Northriver Holdings Ltd | Real estate | 2026 |
| Northstar Financial Content Ltd | Information & communication | 2020 |
| Northumberland Terrace Management Limited | Households | 2022 |
| Nortruck Services Holdco Ltd | Financial services | 2026 |
| Noswal Limited | Wholesale & retail | 1971 |
| NOT Another Brand Ltd | Information & communication | 2026 |
| Notorious D.O.G. Ltd | Wholesale & retail | 2020 |
| Notting Hill Building Consultancy Limited | Construction | 2012 |
| Nouj Air Services Limited | Transport & logistics | 2020 |
| Nouti Limited | Health & social care | 2021 |
| Nova Roofing & Building Ltd | Construction | 2024 |
| NP Investment Management Limited | Administrative & support | 2017 |
| NP Technologies Global Ltd | Professional & scientific | 2024 |
| NPH Red Oak 2 Limited | Real estate | 2024 |
| NPH Red Oak 3 Limited | Extraterritorial | 2024 |
| Npicariello Limited | Wholesale & retail | 2007 |
| Npro Investments 3 Limited | Extraterritorial | 2024 |
| Npro Investments Ltd | Real estate | 2021 |
| Nresearch (UK) Limited | Manufacturing | 1997 |
| Nrth Ltd | Information & communication | 2024 |
| NS Structured Solutions Ltd | Information & communication | 2025 |
| Nsingo & Company Ltd | Information & communication | 2009 |
| NSJ Commercial Management Ltd | Real estate | 2020 |
| NSS Security Solutions Ltd | Administrative & support | 2012 |
| NTA Psychological Screening Ltd | Professional & scientific | 2015 |
| NTN Global Consultants Limited | Information & communication | 2014 |
| Nuaxia Limited | Professional & scientific | 2016 |
| Nuestras Casas Limited | Financial services | 2024 |
| Number 8 the Jewellers Ltd | Wholesale & retail | 2024 |
| Number Eight and TEN Ashford Crescent Management Company Limited | Households | 1972 |
| Number Hive Ltd | Information & communication | 2022 |
| Numbers 4 FUN Ltd | Professional & scientific | 2015 |
| Nurama Ltd | Information & communication | 2025 |
| Nurture & Partners Ltd | Administrative & support | 2019 |
| Nuskin Solutions Ltd | Other services | 2023 |
| Nutritionist's Blend Limited | Manufacturing | 2016 |
| Nutsdown Limited | Administrative & support | 1978 |
| Nuvora Capital Ltd | Professional & scientific | 2025 |
| Nuwave Display Limited | Professional & scientific | 2010 |
| NVK Accountancy Ltd | Professional & scientific | 2017 |
| Nvma Consulting Ltd | Information & communication | 2014 |
| Nwgd Services Limited | Administrative & support | 2017 |
| Nyhc Ltd | Hospitality | 2025 |
| Nytron Developments Limited | Real estate | 2001 |
| O Shaughnessy Commercial Services Ltd | Professional & scientific | 2015 |
| O.S Electrical Services Ltd | Construction | 2019 |
| O.Scarr Ltd | Manufacturing | 2026 |
| Oak & Olive Carpentry Ltd | Manufacturing | 2025 |
| Oak Grange Farm Ltd | Manufacturing | 2023 |
| Oak Sash Company Limited | Manufacturing | 2016 |
| Oakfield Capital General Partner LLP | | 2017 |
| Oakfield Capital III LP | | 2017 |
| Oakfield Capital III Satellite LP | | 2021 |
| Oakfield Capital Partners LLP | | 2008 |
| Oakfield FP LP | | 2017 |
| Oaks Farm Receptions Limited | Administrative & support | 2013 |
| Oaksbridge Management Ltd | Information & communication | 2023 |
| Oasis Cladding Ltd | Construction | 1997 |
| Oatlands Glass & Glazing Services Limited | Construction | 1976 |
| OAX Business Services Ltd | Professional & scientific | 2019 |
| Obrsound Ltd | Information & communication | 2023 |
| Observe Technologies Limited | Information & communication | 2016 |
| Obsidian Keep Limited | Real estate | 2015 |
| Oc&S Consulting Ltd | Real estate | 2019 |
| Ocean Glory Commodities Ltd | Wholesale & retail | 2024 |
| Ocean@Home Limited | Real estate | 2021 |
| Oconee Bell Ltd | Households | 2018 |
| Octo House Ltd | Professional & scientific | 2019 |