| MV Consulting Invest Ltd | Extraterritorial | 2025 |
| MVG Carpentry & Building Limited | Construction | 2024 |
| Mweni Limited | Transport & logistics | 2018 |
| MWL Property Ltd | Construction | 1999 |
| My Ikigai Ltd | Hospitality | 2016 |
| My Property Key Services Ltd | Real estate | 2024 |
| My Tracker Group Limited | Education | 2017 |
| Mynudge Concepts Inc. | | 2025 |
| MZK Food Invest Ltd | Extraterritorial | 2025 |
| MZK Food Ltd | Extraterritorial | 2025 |
| N J N Groundworks Limited | Construction | 2022 |
| N U Steps Ltd | Education | 2008 |
| N V Dover International Food Centre Ltd | Wholesale & retail | 2024 |
| Nabob Limited | Professional & scientific | 2015 |
| Nadd Ltd | Real estate | 2025 |
| NAG Services Limited | Professional & scientific | 2003 |
| Nail Blossom Ltd | Other services | 2023 |
| Napana, Inc., | | 2019 |
| Natkin Limited | Households | 1989 |
| Nature Consulting Limited | Information & communication | 2019 |
| Naughtical Marine Ltd | Wholesale & retail | 2022 |
| Navenu, Inc. | | 2023 |
| Navitas Management Ltd | Professional & scientific | 2022 |
| Naya 4 UK Ltd | Administrative & support | 2024 |
| Neerosoft Solutions Ltd | Information & communication | 2026 |
| Neil Scrivener Stonemason Limited | Manufacturing | 2026 |
| Neil Smith Retouching Limited | Professional & scientific | 2019 |
| Neptune Repairs Ltd | Construction | 2025 |
| Nervae Solutions Ltd | Wholesale & retail | 2025 |
| Netlock Limited | Real estate | 2003 |
| New Build Landscapes Ltd | Construction | 2017 |
| New Line Networks LLC | | 2014 |
| Newcombe Berry Estate Ltd | Real estate | 2020 |
| News in Ltd | Wholesale & retail | 2018 |
| Nexus Geotec Ltd | Construction | 2023 |
| Nick Howson Limited | Construction | 2011 |
| Nick Ovenden Plant Hire Limited | Construction | 2004 |
| Nicole James Catering Limited | Hospitality | 2014 |
| Nigel Lang Ltd | Professional & scientific | 2006 |
| Night and Day Collection Ltd | Professional & scientific | 2023 |
| Nija Invest Ltd | Extraterritorial | 2009 |
| Nimal Food and Wine Ltd | Wholesale & retail | 2026 |
| Nimble APE Ltd | Information & communication | 2013 |
| Nimbusync Ltd | Wholesale & retail | 2025 |
| Ninthu’S RN Ltd | Hospitality | 2026 |
| Nito Ltd | Wholesale & retail | 2022 |
| Njord Ltd | Professional & scientific | 2023 |
| Njord Subsea Ltd | Professional & scientific | 2024 |
| NJW Associates (UK) Limited | Professional & scientific | 2005 |
| NK & MK Transport Limited | Transport & logistics | 2008 |
| Nlcbproperties Ltd | Real estate | 2025 |
| NO MAS Vello Investment Limited | Other services | 2011 |
| Norta Trading Ltd | Wholesale & retail | 2024 |
| North Barracks Deal Management Company Limited | Households | 2019 |
| North Downs Consulting Limited | Professional & scientific | 2023 |
| North of England Properties Ltd | Real estate | 2022 |
| Northdown Dahley (Commercial) Ltd | Financial services | 2024 |
| Northdown Financial Services Limited | Financial services | 2021 |
| Northdown Property Services Ltd | Real estate | 2023 |
| Northdown Property Solutions Ltd | Real estate | 2025 |
| Northon's Media PR & Marketing Ltd | Information & communication | 2018 |
| Northstar Investments Group Ltd | Real estate | 2025 |
| Norton Timber Limited | Manufacturing | 2006 |
| NOT Just Door’S Ltd | Construction | 2024 |
| Notting Hill Heating Limited | Construction | 2022 |
| Nova Genesis Ltd | Construction | 2026 |
| Nova Pizza Limited | Hospitality | 2026 |
| NSL Fire & Security Ltd | Administrative & support | 2013 |
| Nursery Mews Management Eythorne Limited | Real estate | 2025 |
| Nusystem Holdings Limited | Other services | 2017 |
| Nusystem Limited | Hospitality | 2014 |
| NUU Home Group Ltd | Health & social care | 2025 |
| NVL UK Construction Ltd | Construction | 2020 |
| NVL UK Consulting Ltd | Administrative & support | 2020 |
| O.J.M Cars Invest Ltd | Extraterritorial | 2020 |
| O.J.M Cars Ltd | Extraterritorial | 2020 |
| Oakdale Care Home Ltd | Health & social care | 2016 |
| Oakdale Holdings Limited | Other services | 2017 |
| Oakdown Estates Ltd | Real estate | 2024 |
| OB Tree Service Ltd | Administrative & support | 2022 |
| Obulus Group Limited | Financial services | 2018 |
| Oceanview Consultancy Limited | Information & communication | 1994 |
| Odum's House Ltd | Real estate | 2023 |
| Odyo Ltd | Administrative & support | 2018 |
| Old Colliery Engineering Ltd | Professional & scientific | 2025 |
| Old Orchards Management Company Limited | Households | 2022 |
| Oliver Carpets Ltd | Wholesale & retail | 2005 |
| Olivia's Sales Limited | Wholesale & retail | 2021 |
| Olson-Welsh Limited | Information & communication | 2020 |
| Olympus Learning Collective Ltd | Education | 2024 |
| Omex London Ltd | Wholesale & retail | 2018 |
| Omnia Property Investing Ltd | Real estate | 2022 |
| Omnimax International, LLC | | 2025 |
| Once Upon the MAT Limited | Education | 2025 |
| Oneiric Therapy Limited | Health & social care | 2019 |
| Onepoint Vending Group Ltd | Wholesale & retail | 2025 |
| Onlyouagency Ltd | Wholesale & retail | 2023 |
| Open PN Invest Ltd | Extraterritorial | 2025 |
| Open PN Ltd | Extraterritorial | 2025 |
| Open Space Labs CIC | Information & communication | 2026 |