| MRG Electrical Ltd | Construction | 2025 |
| MRS Building Service Ltd | Construction | 2014 |
| MS Beauty Ltd | Other services | 2023 |
| Msautotech Twickenham Limited | Wholesale & retail | 2014 |
| MTC Installations Limited | Other services | 2017 |
| MTF Engineering Consultancy Ltd | Professional & scientific | 2018 |
| MU Chado Studio Ltd | Administrative & support | 2026 |
| Muhley Property Limited | Hospitality | 1991 |
| Mulberry Accounting Solutions Ltd | Professional & scientific | 2021 |
| Mulberry Place (Woodley) Residents Management Company Limited | Households | 2017 |
| Mummas in Mind Community Interest Company | Health & social care | 2026 |
| Munemo Ltd | Health & social care | 2021 |
| Munstead Property and Investment Company Limited | Construction | 1935 |
| Murder Ball Legacy CIC | Arts & recreation | 2022 |
| Mustard Roots LLP | | 2025 |
| Muzzy Turkish Barbers Limited | Other services | 2025 |
| MVC Properties Ltd | Real estate | 2021 |
| MW Automotive Limited | Wholesale & retail | 2015 |
| MW Equine Shoeing Services Limited | Agriculture & fishing | 2016 |
| MWA Enterprises Ltd | Professional & scientific | 2020 |
| Mwgc Leisure Limited | Professional & scientific | 2003 |
| Mwilsons Properties Ltd | Real estate | 2024 |
| My Doggy Day Care Ltd | Other services | 2018 |
| My Go Coffee Ltd | Manufacturing | 2024 |
| My Labourer Ltd | Information & communication | 2025 |
| My Property Claim Limited | Financial services | 2012 |
| Myagi Kagi Ltd | Real estate | 2017 |
| Myln Ltd | Arts & recreation | 2024 |
| Mymoto Limited | Extraterritorial | 2011 |
| Mypath Limited | Health & social care | 2012 |
| Mytchett Masala Limited | Hospitality | 2026 |
| N J W Bookkeeping & Accountancy Limited | Professional & scientific | 2010 |
| Nabil Production Ltd | Information & communication | 2025 |
| Nadco Properties Limited | Real estate | 2025 |
| Naderzadeh Trading Ltd | Wholesale & retail | 2018 |
| Nail KIT Ltd | Other services | 2025 |
| Namaste Wedding Planner Ltd | Other services | 2023 |
| Namco American Ltd | Wholesale & retail | 2009 |
| Nanaki Holdings Ltd | Real estate | 2020 |
| Nandanavanam Limited | Real estate | 2024 |
| Nash Electrical Services LLP | | 2016 |
| Nashbu Consultancy Ltd | Professional & scientific | 2024 |
| Nashbu Investments Ltd | Real estate | 2020 |
| Nasme Aero Consultants Limited | Professional & scientific | 2025 |
| Natalie Isherwood Limited | Professional & scientific | 2006 |
| Natalie Sutton Ltd | Professional & scientific | 2023 |
| Nation Guarding Ltd | Administrative & support | 2024 |
| Natlsa Global Limited | Health & social care | 2018 |
| Natural Health Taichi Ltd | Health & social care | 2024 |
| Natural Instinct Limited | Manufacturing | 2009 |
| Nature and Nurture Farm CIC | Education | 2025 |
| Navigating Life Ltd | Health & social care | 2024 |
| Navratri Estate Limited | Real estate | 2024 |
| Nawis Ltd | Manufacturing | 2026 |
| NAZ Electrical Ltd | Construction | 2022 |
| NBU Consulting Limited | Wholesale & retail | 2014 |
| NCM Homes Limited | Construction | 2015 |
| NDA Consulting Limited | Professional & scientific | 2004 |
| NDH Connectivity Ltd | Professional & scientific | 2024 |
| Ndxing Ltd | Financial services | 2025 |
| Neale Butler Limited | Professional & scientific | 2011 |
| Neale Turk Rochfort LLP | | 2017 |
| Neat Enterprise Limited | Administrative & support | 2025 |
| Neat Nest Refresh Limited | Professional & scientific | 2026 |
| Nebula Network Equipment Trading Ltd | Wholesale & retail | 2024 |
| Needify.Co Ltd | Wholesale & retail | 2025 |
| Neehaa Ltd | Construction | 2026 |
| Nehra Consultant Limited | Health & social care | 2011 |
| Neil Chitre Consulting Limited | Professional & scientific | 2018 |
| Neil Dobson Consultancy Ltd | Administrative & support | 2012 |
| Nell @ Action Ltd | Professional & scientific | 2008 |
| Nelson Environment and Transport Services Ltd | Professional & scientific | 2026 |
| Nelson's Access Flooring Ltd | Construction | 2016 |
| Nerd Herd Ltd | Manufacturing | 2024 |
| Nest Resorts Limited | Professional & scientific | 2011 |
| Nestable Technologies Limited | Information & communication | 2025 |
| Nestor Electronics Limited | Information & communication | 1994 |
| NET Coverage Solutions Ltd | Information & communication | 2004 |
| NET Holdings Limited | Information & communication | 2005 |
| Netcargo UK Ltd | Transport & logistics | 2005 |
| Netgrp Limited | Manufacturing | 2023 |
| Network Isles CIC | Information & communication | 2024 |
| Neuro Natives Limited | Professional & scientific | 2024 |
| Neutron Ltd | Professional & scientific | 2026 |
| New Apostolic Church UK | Other services | 2012 |
| New Beginnings Health Care LT Ltd | Health & social care | 2019 |
| New Beginnings Healthcare Services Ltd | Health & social care | 2021 |
| New Care Horizons (the Pinnacle Weymouth) Limited | Construction | 2013 |
| New Inn Court Management Company Limited | Households | 2002 |
| New Look Carpet Care Limited | Administrative & support | 2002 |
| New Loon Moon Limited | Wholesale & retail | 1995 |
| New Mile Court Management Company Limited | Households | 1998 |
| New Suravi Limited | Other services | 2013 |
| New World Recycling Ltd | Water & waste | 2023 |
| New World Strategies Marketing Limited | Professional & scientific | 2025 |
| Newcombe Properties Limited | Extraterritorial | 1986 |
| Newell Hall Limited | Households | 2002 |
| News Associates Limited | Extraterritorial | 2020 |
| Newtons Consulting Ltd | Professional & scientific | 2025 |
| Nexmechs Ltd | Information & communication | 2021 |