| Nsscpcl Limited | Other services | 2021 |
| Nsym Limited | Information & communication | 2025 |
| NT CPO Ltd | Administrative & support | 2026 |
| NT Distributors Ltd | Wholesale & retail | 2026 |
| NT Safeguarding & Quality Consultancy Ltd | Professional & scientific | 2026 |
| Ntungiye Ltd | Administrative & support | 2023 |
| NTW Davis Ltd | Hospitality | 2021 |
| NU Architectural Ltd | Construction | 2019 |
| Nu-Gen Limited | Financial services | 2025 |
| Nu-Look Interiors (UK) Limited | Construction | 2011 |
| Nu-Wave Auto Worx Ltd | Wholesale & retail | 2020 |
| Nugerontix Limited | Professional & scientific | 2007 |
| Numaria Limited | Health & social care | 2023 |
| Number 22 Cafe Ltd. | Hospitality | 2021 |
| Number Four Developments Ltd | Real estate | 2023 |
| Numerounohousing Ltd | Real estate | 2025 |
| NUR Smiles Ltd | Health & social care | 2026 |
| Nurse LED by Leeann Ltd | Other services | 2026 |
| Nuturenest Recruitment Ltd | Administrative & support | 2024 |
| Nuville Ltd | Real estate | 2020 |
| Nuvision (UK) Limited | Professional & scientific | 2014 |
| Nuvision Properties Ltd | Real estate | 2022 |
| Nuvme Ltd | Arts & recreation | 2025 |
| NV Events Ltd | Arts & recreation | 2017 |
| NVA Workshop Limited | Wholesale & retail | 2025 |
| Nvrmind Ltd | Wholesale & retail | 2025 |
| NW Buildings Limited | Real estate | 2017 |
| NW Delivery Ltd | Other services | 2024 |
| NW Nest Limited | Hospitality | 2026 |
| NW Property Development Limited | Real estate | 2017 |
| Nwsw Software Limited | Information & communication | 2021 |
| NXN Properties Limited | Real estate | 2024 |
| Nxumalo Express Ltd | Transport & logistics | 2025 |
| Nyota Scouting Ltd | Professional & scientific | 2026 |
| Nyounga Limited | Health & social care | 2019 |
| NZZ Consultants Limited | Health & social care | 2018 |
| Néviv Ltd | Wholesale & retail | 2025 |
| O & E Property Solutions Limited | Real estate | 2017 |
| O & G Empire Ltd | Hospitality | 2022 |
| O a Silver Service Ltd | Transport & logistics | 2020 |
| O G Stubbs Limited | Construction | 2015 |
| O&A Home Ltd | Real estate | 2025 |
| O&L MEP Services Limited | Professional & scientific | 2024 |
| O'Connor Property Services Limited | Real estate | 2019 |
| O'Sullivan & Edmonds Limited | Agriculture & fishing | 2013 |
| O. Green Property Ltd | Construction | 2026 |
| O.D.H Enterprises Ltd | Other services | 2022 |
| O.D.H Properties Ltd | Real estate | 2026 |
| O.Dunlop Holdings Limited | Financial services | 2024 |
| Oak Tree Avenue Ltd | Wholesale & retail | 2022 |
| Oak-Ngate (Stoke) Limited | Construction | 2017 |
| Oakamoor Forest Lodges Holdings Ltd | Financial services | 2025 |
| Oakbray Limited | Manufacturing | 1975 |
| Oakbray Management Ltd | Manufacturing | 2023 |
| Oakes Homes Ltd | Real estate | 2019 |
| Oakhill 682 Ltd | Hospitality | 2024 |
| Oakleys Farm Ltd | Agriculture & fishing | 2020 |
| Oakm Limited | Administrative & support | 2021 |
| Oakmoor Driveways Ltd | Construction | 2025 |
| Oakmoor Electrical Ltd | Construction | 2026 |
| Oakmoore Construction Services Limited | Construction | 2023 |
| Oaksward Financial Limited | Professional & scientific | 2020 |
| Oaktreez Ltd | Information & communication | 2018 |
| Oakwell Retail Ltd | Wholesale & retail | 2026 |
| Oakwood Residential Care Services Ltd | Health & social care | 2025 |
| OAS Air Conditioning Limited | Manufacturing | 2011 |
| Oasis Plant and Haulage Limited | Administrative & support | 2024 |
| Oasis Traders International Co. Ltd | Wholesale & retail | 2025 |
| Oatbakers Ltd | Hospitality | 2020 |
| Oatcake Properties Ltd | Real estate | 2016 |
| Oatcuisine Limited | Hospitality | 2013 |
| Obag Properties Ltd | Real estate | 2020 |
| Obra Sitio Limited | Wholesale & retail | 2022 |
| Obsequium Limited | Professional & scientific | 2016 |
| OBW Holdings Limited | Real estate | 2023 |
| OC Group Holdings Ltd | Real estate | 2020 |
| OC Property and Development Ltd | Households | 2025 |
| Ocbidco Limited | Financial services | 2021 |
| Occasions Catering for YOU Limited | Hospitality | 2013 |
| Oceanic Shipping & Logistics Ltd | Transport & logistics | 2020 |
| Ocnewco UK Ltd | Wholesale & retail | 2014 |
| Octane Performance Fuelling Ltd | Wholesale & retail | 2024 |
| Octatechhouse Ltd | Wholesale & retail | 2026 |
| Ocuk Limited | Information & communication | 1999 |
| Ocuocu Ltd | Transport & logistics | 2025 |
| ODD 01 Limited | Construction | 2024 |
| ODD Panda Limited | Manufacturing | 2025 |
| Odeon Antiques Limited | Real estate | 2019 |
| ODS Health Limited | Health & social care | 2025 |
| Oeco Property Ltd | Real estate | 2025 |
| OFF Plan Dubai Property Limited | Real estate | 2025 |
| Office Conversion Limited | Construction | 2021 |
| Office Essentials Emporium Limited | Wholesale & retail | 2025 |
| Official Company Data Limited | Information & communication | 2020 |
| Offshelf Ltd. | Professional & scientific | 1972 |
| Ofoodi Limited | Wholesale & retail | 2023 |
| OG Travel Ltd | Transport & logistics | 2026 |
| Ogefine Ltd | Wholesale & retail | 2025 |
| Oggy Ltd | Wholesale & retail | 2018 |
| Oggy's Bar of Hanley Ltd | Hospitality | 2020 |