| Nurish Ltd | Health & social care | 2020 |
| Nurselo Limited | Health & social care | 2009 |
| Nursery Crescent 1963 Limited | Extraterritorial | 2014 |
| Nursery Works Ltd | Real estate | 2001 |
| Nurtura Living Group Ltd | Real estate | 2025 |
| Nurtura Living Management Company Ltd | Real estate | 2025 |
| Nurture Nova Ltd | Education | 2025 |
| Nustec Group Ltd | Administrative & support | 2020 |
| Nutbrown Property Rentals Limited | Real estate | 2017 |
| Nutrein Ltd | Wholesale & retail | 2022 |
| Nutridiet Ltd | Health & social care | 2020 |
| Nutrition 4 Peak Performance Limited | Health & social care | 2021 |
| Nutritional Sciences Ltd | Other services | 2021 |
| NUTRITIONIST1ST Ltd | Health & social care | 2023 |
| Nutritoken Ltd | Information & communication | 2022 |
| Nutrovix Ltd | Wholesale & retail | 2026 |
| Nuttcase Limited | Other services | 2010 |
| Nutwood Secure Storage Limited | Real estate | 2020 |
| Nutwood Trading Estate Management Company Limited | Administrative & support | 1985 |
| Nuvida Ltd | Wholesale & retail | 2008 |
| Nuvoro Building Solutions Limited | Construction | 2025 |
| Nuweira RMN Ltd | Health & social care | 2023 |
| Nuyu Wellness Ltd | Health & social care | 2024 |
| NVM Group Ltd | Professional & scientific | 2022 |
| Nvrdevelopments Ltd | Construction | 2023 |
| NVS Plumbing & Heating Limited | Construction | 2016 |
| NW ERP Ltd | Information & communication | 2025 |
| NW Ribs Ltd | Administrative & support | 2016 |
| NW Roofing & Property Development Ltd | Real estate | 2025 |
| NWG Network | Health & social care | 2008 |
| NWM Renovation Limited | Construction | 2024 |
| NWS Trustees Limited | Financial services | 2026 |
| NWT Holdings Limited | Financial services | 2019 |
| NWT Intermodal Limited | Transport & logistics | 2021 |
| NX Spotless UK Limited | Transport & logistics | 2026 |
| NXG Accountants Ltd | Professional & scientific | 2016 |
| NXP Productions Limited | Information & communication | 2021 |
| NXT GEN Estates Ltd | Real estate | 2024 |
| Nxtion Food Market Hillsborough Ltd | Wholesale & retail | 2026 |
| Nxtion Food Market Ltd | Wholesale & retail | 2024 |
| NY Investments Limited | Real estate | 1988 |
| NY Optical Ltd | Wholesale & retail | 2018 |
| NYA Music Ltd | Information & communication | 2023 |
| Nyamuz Limited | Health & social care | 2023 |
| Nyana Ltd | Wholesale & retail | 2025 |
| NYC Cash & Carry Limited | Wholesale & retail | 2025 |
| NYJ Holdings Limited | Professional & scientific | 2016 |
| Nypr Space Ltd | Real estate | 2019 |
| Nyumnyum Ltd Limited | Financial services | 2025 |
| NYX Limited | Information & communication | 2026 |
| Nyxn Commercial Limited | Wholesale & retail | 2026 |
| Nyxn Limited | Other services | 2026 |
| Nz-One Limited | Wholesale & retail | 2023 |
| Nzingo Limited | Health & social care | 2021 |
| Nzuko UMU Abia South Yorkshire Ltd | Other services | 2026 |
| Nzuri Health Ltd | Arts & recreation | 2008 |
| O & S Developments Ltd | Real estate | 2024 |
| O B F Limited | Real estate | 2003 |
| O E Services Limited | Administrative & support | 2004 |
| O R Education Holdings Limited | Administrative & support | 2002 |
| O R Education Limited | Administrative & support | 2002 |
| O T E Travel Ltd | Transport & logistics | 2025 |
| O&E Partnerships Limited | Professional & scientific | 2021 |
| O&E Property Investments Ltd | Real estate | 2021 |
| O'Hara Capital SPE Limited | Real estate | 2023 |
| O'Hara's Spiced RUM Limited | Manufacturing | 2012 |
| O'Penchill Limited | Health & social care | 2015 |
| O'Rourke Specialist Vehicles Ltd | Wholesale & retail | 2026 |
| O.C. Dori Ltd | Professional & scientific | 2010 |
| O.H Joint Property Ventures Ltd | Real estate | 2026 |
| O.R.B Electrical Services Ltd | Administrative & support | 2017 |
| Oades Residential Surveying Ltd | Professional & scientific | 2025 |
| Oaegis Limited | Construction | 2013 |
| Oagtn Technologies Limited | Information & communication | 2023 |
| Oaii's Ltd | Hospitality | 2023 |
| Oak Dene Building Solutions Limited | Construction | 2021 |
| Oak Entertainment Limited | Professional & scientific | 2023 |
| Oak House Restaurant Ltd | Hospitality | 2019 |
| Oak Lets Yorkshire Limited | Households | 2022 |
| Oak Mechanical Limited | Construction | 2012 |
| Oak Rentals Limited | Real estate | 2025 |
| Oak Tree Assets Ltd | Real estate | 2021 |
| Oak View Eckington Management Company Limited | Households | 2025 |
| Oakapple Community Farm | Agriculture & fishing | 2020 |
| Oakapple Designs Ltd | Administrative & support | 2004 |
| Oakapple Online Limited | Wholesale & retail | 2013 |
| Oakbridge Estates Ltd | Construction | 2024 |
| Oakbrook Coffee Co Limited | Hospitality | 2017 |
| Oakbrook Electrical Ltd | Construction | 2016 |
| Oakbrook Estates Ltd | Real estate | 2023 |
| Oakbrook Pyoneers Ltd | Real estate | 2025 |
| Oakbrook Rafters Limited | Hospitality | 2013 |
| Oakbrook Road Ltd | Real estate | 2020 |
| Oakbrook Services Ltd | Other services | 2015 |
| Oakbrook Tutors LLP | | 2024 |
| Oakbrook Upholstery Ltd | Manufacturing | 2013 |
| Oakcroft Mews Management Limited | Households | 2021 |
| Oakdale Court Management Limited | Households | 2003 |
| Oakdale Joinery Ltd | Construction | 2012 |
| Oakdale Property Management Ltd | Households | 2022 |