| MUM Histo Limited | Health & social care | 2016 |
| Mumbleswerve Ltd | Financial services | 2011 |
| Muscle Tank Ltd | Wholesale & retail | 2025 |
| Music Creation Limited | Arts & recreation | 2009 |
| Music for Film Limited | Arts & recreation | 2010 |
| Mustafa Estates Ltd | Real estate | 2023 |
| Mvjd Electrical Ltd | Manufacturing | 2026 |
| MVP Ventures (Group Services) Limited | Professional & scientific | 2021 |
| MVP Ventures (Holdings) Limited | Financial services | 2021 |
| MW Design & Publishing Limited | Information & communication | 2014 |
| MW67 Locations Limited | Information & communication | 2018 |
| My Auction Ltd | Real estate | 2019 |
| My Business Activities Limited | Professional & scientific | 2021 |
| My Green Room Ltd | Information & communication | 2024 |
| My Health Biotics Limited | Wholesale & retail | 2025 |
| Myryad Systems Limited | Professional & scientific | 1993 |
| Mystoreuk Ltd | Wholesale & retail | 2026 |
| N L H Homes Ltd | Extraterritorial | 2023 |
| N&N-Joy Ltd. | Hospitality | 2026 |
| N.D.R. Contracting Limited | Construction | 2005 |
| N.E.Aviation Ltd | Professional & scientific | 2026 |
| N.O.P. Hospitality Consulting Ltd | Administrative & support | 2018 |
| Nabarro Technical Services (Consulting) Ltd | Professional & scientific | 2011 |
| Naderav Holdings Limited | Real estate | 2019 |
| Nado Properties Ltd | Real estate | 2019 |
| Nahda Fine Art Limited | Other services | 2019 |
| Nailed IT Stunts Ltd | Arts & recreation | 2017 |
| Nails Diva Ltd | Other services | 2024 |
| Nang Topco Limited | Other services | 2020 |
| Nani Hoku Limited | Real estate | 2024 |
| Natalie Kingham Limited | Professional & scientific | 2021 |
| Natalie's Coaching Club Ltd | Education | 2024 |
| Natasha Popoola Ltd | Information & communication | 2017 |
| Nathan Stickley Limited | Arts & recreation | 2010 |
| Natural BOW Treats Ltd | Manufacturing | 2025 |
| Natural Unique Mind Ltd | Professional & scientific | 2022 |
| Natvic Construction Limited | Construction | 2011 |
| Navah-Consulting Ltd | Professional & scientific | 2018 |
| Nazaara Estates Limited | Real estate | 2025 |
| NB Commissioning Management Ltd | Professional & scientific | 2025 |
| NCA Investments Limited | Financial services | 2023 |
| NED PR Ltd | Professional & scientific | 2022 |
| Needham Chalks (HAM) Limited | Mining & quarrying | 1993 |
| Negawattsource Limited | Professional & scientific | 2014 |
| Neighbourhood Pathways Improvement Ltd | Health & social care | 2026 |
| Neil Ventre Accountancy Ltd | Professional & scientific | 2021 |
| Nelson & Sons Plumbing & Heating Ltd | Construction | 2024 |
| Neon Artisan Ltd | Professional & scientific | 2018 |
| Neptune Gasguard Services Ltd | Construction | 2026 |
| Neptune International Trading Limited | Wholesale & retail | 1973 |
| Nest & Vine Ltd | Construction | 2024 |
| Netbar Consultants Ltd | Construction | 2005 |
| Network 21 Limited | Construction | 2026 |
| Neuromodulation Market Access Ltd | Professional & scientific | 2022 |
| Neuroreport Ltd | Health & social care | 2025 |
| New Crossways Ltd | Real estate | 2024 |
| New GEN Fitness Limited | Other services | 2020 |
| New Harts Productions Ltd | Professional & scientific | 2011 |
| New Road Clinic Limited | Health & social care | 2021 |
| Newlands Farm Holdings Ltd | Financial services | 2020 |
| Newman Capital Holdings Ltd | Financial services | 2025 |
| Newon Electrical Services Ltd | Construction | 2023 |
| Newstraid Benevolent Fund | Other services | 2006 |
| Newtechnos Limited | Professional & scientific | 2018 |
| Nexo Properties Ltd | Real estate | 2018 |
| Next GEN Management Ltd | Professional & scientific | 2024 |
| Next Steps Training and Coaching Ltd | Education | 2020 |
| Nextgrid Consulting Ltd | Professional & scientific | 2025 |
| NG Residential Ltd | Real estate | 2023 |
| NH Publishing Limited | Information & communication | 2005 |
| Niara Software Solutions Ltd | Administrative & support | 2025 |
| Nicholls & Sons Developments Limited | Real estate | 2020 |
| Nicolealvin Ltd | Wholesale & retail | 2011 |
| Nigel Purkiss Financial Planning Ltd | Professional & scientific | 2020 |
| Nils Salon Ltd | Other services | 2025 |
| Nine Spaces Consultancy Limited | Professional & scientific | 2024 |
| NINE87 Group Limited | Construction | 2022 |
| Ninetythree Creative Ltd | Arts & recreation | 2025 |
| Njdunn Geotechnical Ltd. | Construction | 2015 |
| NJF Training Ltd | Professional & scientific | 2023 |
| NN Works Limited | Professional & scientific | 2017 |
| NO 14 BS Limited | Hospitality | 2025 |
| NO More Boring Papers Limited | Professional & scientific | 2022 |
| NO REP Apparel Limited | Wholesale & retail | 2023 |
| Noah Green Ltd | Information & communication | 2020 |
| Noble Heating & Plumbing Limited | Construction | 2004 |
| Noble Knight Fitness Ltd | Arts & recreation | 2025 |
| Nockolds Consulting Limited | Professional & scientific | 2021 |
| Nockolds Trust Corporation Limited | Administrative & support | 2021 |
| Nockolds Wealth Limited | Financial services | 2015 |
| Nodedoubt Ltd | Information & communication | 2026 |
| Nomada Properties Limited | Households | 2019 |
| Nomadic Education Community Interest Company | Education | 2013 |
| Nomos Advisory Limited | Professional & scientific | 2018 |
| NON Stop Cleaninguk Ltd | Administrative & support | 2026 |
| Norfolk Nirvana Limited | Households | 2021 |
| Norris Steam Investments Ltd | Real estate | 2009 |
| Norris Steam Services (London) Limited | Manufacturing | 1972 |
| Norso Creative Ltd | Information & communication | 2024 |
| North London Fitness Centre Limited | Health & social care | 1996 |