| Money Matters (South East) Limited | Financial services | 2004 |
| Money Matters Wealth Limited | Administrative & support | 2019 |
| Monster Foods Group Limited | Wholesale & retail | 2011 |
| Moon Meadow UK Ltd | Wholesale & retail | 2025 |
| Moore Scaffolding Limited | Construction | 1999 |
| Moorock Consulting Limited | Professional & scientific | 2022 |
| Moorock Developments Ltd | Real estate | 2023 |
| Moraceda Investments Limited | Professional & scientific | 2002 |
| Morganon Ltd | Professional & scientific | 2015 |
| Morris Milton Networks Limited | Information & communication | 2026 |
| Mosley Design Limited | Professional & scientific | 2003 |
| Motonomy Capital Limited | Financial services | 2025 |
| Mould & Turner Builders Merchants Limited | | 1975 |
| Mountesque Limited | Real estate | 2016 |
| MP Refurbishment Limited | Construction | 2005 |
| Mpdsupport Limited | Professional & scientific | 2022 |
| MPG Maintenance Group Limited | Construction | 2013 |
| Mpig Limited | Administrative & support | 2021 |
| MR DO IT ALL Limited | Construction | 2019 |
| MRA Sussex Solutions Limited | Extraterritorial | 2008 |
| MRC TWENTY12 Limited | Information & communication | 2012 |
| MS Consultants London Limited | Professional & scientific | 2015 |
| MSE Group Ltd | Construction | 2018 |
| MSN Roofing Limited | Construction | 2014 |
| MSW Hub Ltd | Real estate | 2026 |
| Mulberry Mews (Dormansland) Limited | Households | 2012 |
| Mulberry Mews Freehold Limited | Households | 2012 |
| Munin Engineering Services Ltd | Professional & scientific | 2024 |
| Musketier EFP | Education | 2026 |
| Musketier Investments Ltd | Professional & scientific | 2026 |
| Muxcom Limited | Information & communication | 2022 |
| My Tech Geek Limited | Other services | 2009 |
| Mydoxvault Ltd | Other services | 2004 |
| Myenhance Ltd | Health & social care | 2014 |
| Mysa Studio Ltd | Professional & scientific | 2024 |
| N-Compass OD Limited | Administrative & support | 2013 |
| N.E.S Welding and Engineering Limited | Professional & scientific | 2025 |
| NAH IT Services Ltd | Information & communication | 2010 |
| Nana's Nibbles Limited | Manufacturing | 2025 |
| Naomi Lockwood Consulting Limited | Administrative & support | 2017 |
| NAP Enterprises Limited | Professional & scientific | 1984 |
| Narconon Trust | Education | 2005 |
| Nash Care Homes Ltd | Health & social care | 2013 |
| Natcon Building Solutions Limited | Construction | 2012 |
| Natcon UK Limited | Construction | 2008 |
| National Test Services Limited | Manufacturing | 2002 |
| Natura Consulting Ltd | Administrative & support | 2015 |
| Natural Evolution (Europe) Limited | Transport & logistics | 2015 |
| Nature Power Trading Limited | Health & social care | 2005 |
| Nature Squared Ltd | Wholesale & retail | 2017 |
| Nebula Technology Solutions Limited | Information & communication | 2012 |
| Neilson Financial Limited | Financial services | 2022 |
| Nerdytech Ltd | Information & communication | 2006 |
| Nesta Investments Limited | Real estate | 1962 |
| Nestedge Asset Management Ltd | Real estate | 2025 |
| Netimpact Consulting & Advisory Ltd | Professional & scientific | 2024 |
| Netnor Ltd. | Professional & scientific | 2014 |
| Neutek Limited | Information & communication | 2015 |
| Nevertime Ltd | Wholesale & retail | 2018 |
| Nevz 01 Ltd | Hospitality | 2024 |
| New Concept General Cleaning Company Limited. | Administrative & support | 1987 |
| New ERA Publications U.K. Limited | Information & communication | 1984 |
| New Evergreen Chinese Limited | Hospitality | 2020 |
| New Home Snags Ltd | Construction | 2020 |
| New Life Kitchens Ltd | Construction | 2025 |
| Newhaze Building Services Limited | Construction | 2003 |
| Newman Electrical Services (South East) Limited | Construction | 2019 |
| Newmarc Consulting Ltd | Professional & scientific | 2011 |
| Next Shoot Ltd | Administrative & support | 2009 |
| Nextline Development Ltd | Information & communication | 2014 |
| Nexus Magazine (UK) Limited | Wholesale & retail | 2006 |
| NG Aviatrix Ltd | Transport & logistics | 2022 |
| NG Beers Limited | Hospitality | 2022 |
| Nicholas Cooper Ltd | Arts & recreation | 2011 |
| Nick and CAM Ltd | Information & communication | 2021 |
| Nicky Heard Limited | Manufacturing | 2013 |
| Nightingale Veterinary Services Ltd | Professional & scientific | 2019 |
| Nightjar Compliance Services Ltd | Professional & scientific | 2026 |
| Nimblenet Ltd | Information & communication | 2018 |
| NINETY3 Build Ltd | Manufacturing | 2025 |
| Ninskadesigns Ltd | Wholesale & retail | 2024 |
| Nireg Capital Holdings Ltd. | Financial services | 2021 |
| Nireg Capital Limited | Hospitality | 2018 |
| NJS Properties Limited | Real estate | 2017 |
| NJW Logistical Solutions Ltd | Professional & scientific | 2026 |
| NN Health Distribution Ltd | Wholesale & retail | 2021 |
| Noble Exterior Cleaning Ltd | Administrative & support | 2026 |
| Noert Ltd | Wholesale & retail | 2018 |
| Noha Partnership LLP | | 2004 |
| Nordcell Limited | Wholesale & retail | 2010 |
| Nordic Conveyor Solutions Ltd | Professional & scientific | 2024 |
| Norscar Properties Limited | Real estate | 2011 |
| North END (East Grinstead) Management Company Limited | Real estate | 2015 |
| Northern Compass Accommodation Ltd | Hospitality | 2023 |
| Norway Street Studios Ltd | Real estate | 2025 |
| Notions London Limited | Wholesale & retail | 2023 |
| Nova Flow Plumbing and Heating Limited | Construction | 2025 |
| Novasil Limited | Wholesale & retail | 2024 |
| Novaturient Ltd | Wholesale & retail | 2026 |
| November Tango Romeo Limited | Financial services | 2015 |