| My Beauty Academy Ltd | Education | 2023 |
| My Dream Mortgage Limited | Financial services | 2023 |
| My PAD Ltd | Real estate | 2013 |
| My Refill Life Limited | Wholesale & retail | 2020 |
| My Rentals Limited | Real estate | 2026 |
| My Vibrant Vitality Limited | Information & communication | 2024 |
| MYA3MBEL Limited | Health & social care | 2024 |
| Mymaterna Ltd | Health & social care | 2026 |
| Mystik Nāga Ltd | Wholesale & retail | 2023 |
| N J Gentry Limited | Education | 2007 |
| N P & P Plastering Ltd | Construction | 2017 |
| NA Installations Limited | Construction | 2015 |
| NAC Interim Ltd | Professional & scientific | 2025 |
| Nadia Rose Interiors Ltd | Professional & scientific | 2025 |
| Nadya Giffen Therapies Ltd | Wholesale & retail | 2023 |
| Naked Lounge Ltd | Other services | 2020 |
| Nannies 4 Grannies Limited | Other services | 2013 |
| Nanny Tech Limited | Information & communication | 2022 |
| NAR Technology Ltd | Information & communication | 2018 |
| Nash JR Care Ltd | Administrative & support | 2025 |
| National Roofing and Building Ltd | Construction | 2023 |
| NDC Finance Consulting Limited | Professional & scientific | 2024 |
| Neal and Smith Ltd | Real estate | 2024 |
| Neal and Smith Rentals Ltd | Real estate | 2017 |
| Neil Mason Construction Ltd | Construction | 2021 |
| NEL Care Limited | Health & social care | 2017 |
| Nemeton Ltd | Professional & scientific | 2021 |
| Neosyne Project Management Limited | Professional & scientific | 2024 |
| Nepara Ltd | Education | 2025 |
| Nero Projects Ltd | Information & communication | 2015 |
| NET I SYS Limited | Professional & scientific | 2006 |
| NET Resonance Ltd | Information & communication | 2014 |
| Netra Ltd | Wholesale & retail | 2021 |
| Neuro Consulting Limited | Information & communication | 2013 |
| Neuro Emdr Ltd | Professional & scientific | 2024 |
| New Eastern Solutions Ltd | Information & communication | 2009 |
| New ERA Aviation Limited | Financial services | 2024 |
| New Haulage Limited | Transport & logistics | 2018 |
| New Order Clean Ltd | Administrative & support | 2021 |
| New York Nails AL5 Ltd | Other services | 2024 |
| Newell Logic Limited | Information & communication | 2026 |
| Newlife Call Center Solutions Ltd | Information & communication | 2019 |
| Newmac Freeholds Limited | Real estate | 2008 |
| Newmac Properties Ltd | Real estate | 2007 |
| Newmitre Limited | Energy | 2018 |
| News 4 U (Harpenden) Limited | Wholesale & retail | 2018 |
| Newtek Ltd | Professional & scientific | 2021 |
| Nextgen Properties Limited | Real estate | 2016 |
| Nice Management Ltd | Professional & scientific | 2026 |
| Nick Mawditt Consultancy Ltd | Professional & scientific | 2021 |
| Nickynokeynoo Limited | Professional & scientific | 2019 |
| Nicolas Associates Limited | Information & communication | 1996 |
| Nightingale Capital Advisors (UK) Ltd | Financial services | 2020 |
| Nightlight Entertainment Limited | Information & communication | 2015 |
| Nimar Global LLC (UK) Limited | Wholesale & retail | 2023 |
| Nimble Results Ltd | Information & communication | 2017 |
| NINE9THREE Limited | Professional & scientific | 2024 |
| Nissen Warehousing Limited | Transport & logistics | 1980 |
| Nixolve Consulting Limited | Professional & scientific | 2014 |
| Nnedi Limited | Wholesale & retail | 2025 |
| Noah Design Limited | Administrative & support | 2002 |
| Noah's ARK Harpenden Limited | Education | 2018 |
| Noakes Consulting Limited | Professional & scientific | 2026 |
| Noble Touch Limited | Information & communication | 2010 |
| Noex Ltd | Professional & scientific | 2025 |
| NOH Holdings Limited | Real estate | 2020 |
| Noma Energy Ltd | Professional & scientific | 2024 |
| Nomi Official Ltd | Wholesale & retail | 2025 |
| Nonna's Cafe Ltd | Wholesale & retail | 2024 |
| North Shore Health Limited | Health & social care | 2012 |
| North Star Mobile Beautician Ltd | Other services | 2020 |
| Northdean Property Company Ltd | Real estate | 2019 |
| Northstack Consulting Ltd | Information & communication | 2025 |
| Northstar Analytics Ltd | Information & communication | 2020 |
| Noshaq Ltd | Extraterritorial | 2016 |
| NOT Fine Art Ltd | Wholesale & retail | 2025 |
| Notation Ventures Ltd | Financial services | 2023 |
| Nothingless Ltd | Information & communication | 2022 |
| Nourisol Limited | Professional & scientific | 2021 |
| Novoradiant Limited | Health & social care | 2025 |
| Nrtsquared Limited | Real estate | 2024 |
| NU Concept Construction Ltd | Construction | 2024 |
| Nuovo Group Limited | Information & communication | 2025 |
| Nurtureway Home Care Ltd | Health & social care | 2025 |
| Nutrilogica UK Limited | Administrative & support | 2012 |
| Nutwood Holdings Ltd | Real estate | 2024 |
| NW5 Property Management Limited | Real estate | 2020 |
| NW6 Contractors Ltd | Construction | 2017 |
| NYA Consulting Ltd | Information & communication | 2020 |
| Nyewood Limited | Professional & scientific | 2017 |
| O & D Management Ltd | Health & social care | 2019 |
| O & M Holdings Ltd | Professional & scientific | 2025 |
| O'Connor Property Sourcing Ltd | Real estate | 2023 |
| Oak & Mason Ltd | Professional & scientific | 2023 |
| Oakbury Capital Ltd | Financial services | 2025 |
| Oakdaks Limited | Information & communication | 2011 |
| Oakfield Insurance Brokers Limited | Financial services | 2015 |
| Oaklands Roofing and Building Limited | Construction | 2025 |
| Oakley Media Consulting Limited | Professional & scientific | 2026 |
| Oakview Assets Ltd | Real estate | 2025 |