| NTW Holdings Limited | Financial services | 2017 |
| NTY Consultancy Ltd | Professional & scientific | 2023 |
| Nu-Scene Ltd | Manufacturing | 2022 |
| Nuagex Consultants Ltd | Information & communication | 2025 |
| Nucleus One Ltd | Wholesale & retail | 2016 |
| Nucrete Limited | Construction | 1995 |
| Nude N Lace Ltd | Wholesale & retail | 2023 |
| Nufarm ABF Trustees Limited | Financial services | 2023 |
| Nufarm Crop Products UK Limited | Professional & scientific | 2004 |
| Nufarm UK Limited | Manufacturing | 1993 |
| NUH Grocery Ltd | Wholesale & retail | 2025 |
| Nuhr Ltd | Wholesale & retail | 2024 |
| Numan Ltd | Wholesale & retail | 2025 |
| Number Fourteen Interiors Ltd | Wholesale & retail | 2020 |
| Number One Carpet Cleaning Limited | Administrative & support | 2014 |
| Number One Security & Training Ltd | Administrative & support | 2023 |
| Number Plate Factory UK Limited | Manufacturing | 2025 |
| Nuna Psakan Ltd | Administrative & support | 2026 |
| NUR Real Estate Ltd | Real estate | 2024 |
| Nureh by Maryam Faisal Ltd | Wholesale & retail | 2026 |
| Nurra Health Ltd | Wholesale & retail | 2026 |
| Nurrx Limited | Health & social care | 2025 |
| Nursing & Healthcare Services Experts Ltd | Health & social care | 2014 |
| Nurture and Thrive Ltd | Health & social care | 2025 |
| Nurture Facilities Ltd | Hospitality | 2024 |
| Nurturebyquintessential Limited | Wholesale & retail | 2026 |
| Nurtureu Healthcare Ltd | Health & social care | 2022 |
| Nurvia Limited | Wholesale & retail | 2025 |
| Nusah House Ltd | Wholesale & retail | 2024 |
| Nusrat Foods Ltd | Wholesale & retail | 2020 |
| Nusret Shawarma Ltd | Hospitality | 2024 |
| Nutcracker Hair Ltd | Other services | 2020 |
| Nutlip Limited | Information & communication | 2023 |
| Nutrixo Limited | Manufacturing | 2025 |
| NV Yorkshire Development Ltd | Construction | 2019 |
| NVS Trading Limited | Manufacturing | 2025 |
| NW Dental Ltd | Health & social care | 2025 |
| NW Design Ltd | Arts & recreation | 2016 |
| NW Medispa Ltd | Other services | 2025 |
| NW VEG Limited | Wholesale & retail | 2018 |
| NWM Co Investments Ltd | Construction | 2025 |
| NXG Works Ltd | Information & communication | 2026 |
| NXT Services Ltd | Professional & scientific | 2026 |
| NY Capital Ltd | Hospitality | 2025 |
| NY Health Solutions Ltd | Information & communication | 2015 |
| NY IT and Digital Solutions Ltd | Information & communication | 2025 |
| Nyarai Care Limited | Health & social care | 2015 |
| Nyatesphysio Ltd | Health & social care | 2024 |
| NYK Commercial Ltd | Hospitality | 2024 |
| NYK Group Limited | Financial services | 2025 |
| NYK Halifax Ltd | Hospitality | 2024 |
| NYK Huddersfield Limited | Hospitality | 2026 |
| NYK Leeds Limited | Hospitality | 2023 |
| NYK Leeds Road Ltd | Hospitality | 2024 |
| NYK SFD Limited | Hospitality | 2026 |
| Nyla Clothing Ltd | Wholesale & retail | 2026 |
| Nyloc Limited | Administrative & support | 2005 |
| NYX Route Logistics Ltd | Transport & logistics | 2026 |
| NZ Management Ltd | Real estate | 2020 |
| NZF Worldwide Ltd | Administrative & support | 2016 |
| Nzho Ltd | Wholesale & retail | 2024 |
| O D F Furniture Limited | Wholesale & retail | 2016 |
| O EL Mansoury Ltd | Health & social care | 2022 |
| O R a Í a Skyn Ltd | Other services | 2026 |
| O&Jl Properties Ltd | Households | 2024 |
| O&M Estates Limited | Real estate | 2021 |
| O'Hara Properties Limited | Real estate | 2006 |
| O'Hara Services Limited | Other services | 2001 |
| O'Kek Textile Recycling Ltd | Administrative & support | 2012 |
| O'S Courier Ltd | Transport & logistics | 2025 |
| O.Phils Music and Media Ltd | Arts & recreation | 2024 |
| O2 Essential Group Limited | Wholesale & retail | 2026 |
| O2C Vape Limited | Wholesale & retail | 2018 |
| Oak & Anvil Limited | Wholesale & retail | 2025 |
| Oak & Aura Ltd T/A Madhouse Clearance Outlet Ltd | Wholesale & retail | 2025 |
| Oak H Investments Limited | Real estate | 2016 |
| Oak Hive Property Holdings Limited | Real estate | 2021 |
| Oak House Investments Limited | Real estate | 2016 |
| Oak Initiative Global Impact Ltd | Administrative & support | 2026 |
| Oak Initiative UK CIC | Education | 2021 |
| Oak Lane Barbers Ltd | Other services | 2020 |
| Oak Lane FC Ltd | Hospitality | 2025 |
| Oak Lane Holdings Limited | Extraterritorial | 1985 |
| Oak Lane Plaza Ltd | Construction | 2004 |
| Oak Lane Tyres BFD Ltd | Wholesale & retail | 2022 |
| Oak Motors Limited | Wholesale & retail | 2019 |
| Oak Mount Residence Limited | Real estate | 2020 |
| Oak Tree Flats Ltd | Real estate | 2021 |
| Oakdale Campers Limited | Wholesale & retail | 2020 |
| Oakdale Contractors Limited | Construction | 1997 |
| Oakdale Motors & Recovery Ltd | Wholesale & retail | 2025 |
| Oakes Developments Ltd | | 1985 |
| Oakfield Ltd | Professional & scientific | 2004 |
| Oakforest Joinery Contractors Limited | Construction | 2016 |
| Oakhall Holdings Ltd | Professional & scientific | 2025 |
| Oaks Fish Bar Ltd | Hospitality | 2015 |
| Oakshirebeds Ltd | Wholesale & retail | 2026 |
| Oakswood Financial Compliance Ltd. | Financial services | 2013 |
| Oaktree Homes (Durham) Limited | Construction | 2007 |
| Oakway 1979 Limited | Extraterritorial | 2015 |