| Nuphase Limited | Wholesale & retail | 2026 |
| Nuqi Cosmetics Ltd | Professional & scientific | 2019 |
| Nurburg Motor Ltd | Wholesale & retail | 2026 |
| Nurture in Nature GM CIC | Health & social care | 2026 |
| Nurture Saddleworth Ltd | Other services | 2019 |
| Nurturedessencestudio Ltd | Other services | 2026 |
| Nurturing Hope CIC | Health & social care | 2021 |
| Nurun MED Corporation Ltd | Wholesale & retail | 2024 |
| Nurv Media Ltd | Information & communication | 2017 |
| Nusrat UL Islam Women Education Centre Limited | Education | 2023 |
| Nusrat Ventures Limited | Wholesale & retail | 2025 |
| Nusuk Ltd | Wholesale & retail | 2025 |
| Nutra-Labs Shop Ltd | Wholesale & retail | 2025 |
| Nutriq Ltd | Wholesale & retail | 2026 |
| Nuttall Plant Sales Limited | Wholesale & retail | 2011 |
| Nuvoro Stuff Ltd | Wholesale & retail | 2026 |
| Nvisage Group Ltd | Information & communication | 2024 |
| NW Auto Techz Ltd | Wholesale & retail | 2022 |
| NW Healthy Living Ltd | Wholesale & retail | 2016 |
| NW Hire Solutions Ltd | Other services | 2022 |
| NW Polishing Ltd | Manufacturing | 2025 |
| NW Properties Oldham Ltd | Financial services | 2020 |
| NW Social Work Ltd | Health & social care | 2011 |
| NWA Seniors Tour Ltd | Arts & recreation | 2014 |
| Nwcpp Neuropsychology Ltd | Health & social care | 2025 |
| NWE Consultants Limited | Education | 2026 |
| NWE Properties Limited | Real estate | 2024 |
| NWT Flooring Ltd | Wholesale & retail | 2023 |
| NWX Scaffolding Ltd | Construction | 2023 |
| Nxgn Sports Academy Ltd | Education | 2022 |
| NXT GEN ABC Oldham CIC | Arts & recreation | 2023 |
| NXT GEN Vapours Denton Ltd | Wholesale & retail | 2019 |
| NXT GEN Vapours Hyde Ltd | Wholesale & retail | 2023 |
| NXT GEN Vapours Ltd | Wholesale & retail | 2016 |
| NXT GEN Vapours Mossley Ltd | Wholesale & retail | 2018 |
| NXT Step Education Ltd | Education | 2026 |
| Nxtgen Education Ltd | Education | 2023 |
| NY Motors Ltd | Wholesale & retail | 2024 |
| NY Pizza Co Ltd | Hospitality | 2024 |
| Nyawira Care Limited | Health & social care | 2023 |
| Nydean Care Ventures Limited | Wholesale & retail | 2024 |
| Nyewood Dental Practice Limited | Health & social care | 2010 |
| Nynex Business Communications Limited | Information & communication | 2018 |
| Nyrightworld Ltd | Administrative & support | 2020 |
| NZ Recovery Ltd | Other services | 2025 |
| NZB Upvc Limited | Construction | 2025 |
| O and a Cleaning Limited | Administrative & support | 2026 |
| O B S Leeds Ltd | Hospitality | 2025 |
| O Casement Ltd | Real estate | 2022 |
| O'Donnell Solicitors Limited | Professional & scientific | 2015 |
| O'S Plant Hire Ltd | Administrative & support | 2025 |
| O.E.I. Limited | Other services | 2000 |
| O.K. W Homes Limited | Households | 2024 |
| O.T.C. Consultancy Ltd | Education | 1989 |
| O4B Holdings Limited | Financial services | 2020 |
| O5 Property Limited | Real estate | 2025 |
| Oak & Iron Furniture Store Ltd | Wholesale & retail | 2025 |
| Oak Artisans Holdings Limited | Financial services | 2024 |
| Oak Community Development | Other services | 2007 |
| Oak Deer Ltd | Real estate | 2024 |
| Oak Estates Ltd | Real estate | 2019 |
| Oak Hill Scaffolding Ltd | Construction | 2018 |
| Oak Mews Knutsford (Management Company) Ltd | Households | 2023 |
| Oak Residence Ltd | Households | 2024 |
| Oakburn Securities Limited | Real estate | 1963 |
| Oakdale Mills Property Ltd | Real estate | 2011 |
| Oakdene Care Home Limited | Health & social care | 2017 |
| Oaken Royd Croft Management Limited | Households | 2007 |
| Oakenrod Properties Limited | Real estate | 1965 |
| Oakland Joinery and Construction Limited | Construction | 2018 |
| Oakmont Capital Investments Limited | Professional & scientific | 2014 |
| Oakstone Property Investment Limited | Real estate | 2024 |
| Oaktree 2012 Ltd | Extraterritorial | 2012 |
| Oakwood Interiors Limited | Manufacturing | 2005 |
| Oakworth Manor Residential Home Limited | Health & social care | 2017 |
| Oasis Castle Limited | Real estate | 2021 |
| Oatley Garment Trades Limited | Wholesale & retail | 2022 |
| OBA Millennium Cultural Centre Management Company Limited | Arts & recreation | 2002 |
| Obaid Business Services Ltd | Transport & logistics | 2020 |
| Obash Properties Limited | Real estate | 2020 |
| Obash Security Limited | Administrative & support | 2021 |
| Obbligato Hotels Limited | Hospitality | 2002 |
| Observer Building (Wigan) Management Limited | Households | 2022 |
| Obsidian Atelier Limited | Manufacturing | 2025 |
| Obsidian Detailing Ltd | Administrative & support | 2012 |
| Obtix Fibre Solutions Ltd | Construction | 2025 |
| OCB Store Ltd | Wholesale & retail | 2023 |
| Occupational Management Consultants Limited | Professional & scientific | 2010 |
| Ocean 1989 Ltd | Wholesale & retail | 2023 |
| Ocean Care Homes Ltd | Health & social care | 2021 |
| Oceanfood Limited | Hospitality | 2023 |
| Oceania Capital Holdings LLP | | 2024 |
| Oceania Capital Reserves Limited | Construction | 2021 |
| Oceanic Floors Limited | Extraterritorial | 2013 |
| Octagon Care Ltd | Health & social care | 2017 |
| Octane Recruitment (Holdings) Limited | Other services | 2022 |
| Octane Recruitment Ltd | Administrative & support | 2009 |
| Oculta MCR Ltd | Hospitality | 2020 |
| Odinimir Ltd | Professional & scientific | 2025 |
| Odoi Ltd. | Information & communication | 2015 |