| Motorsport Finance Ltd | Financial services | 2014 |
| Motto Lita Ltd | Information & communication | 2022 |
| Mountain View Properties LLP | | 2012 |
| Mountross Investment Management Ltd. | Financial services | 2015 |
| Mountwood Construction Limited | Construction | 2013 |
| Mountwood Investments Limited | Construction | 2014 |
| Mountwood Limited | Construction | 2013 |
| Mountwood Projects Limited | Construction | 2020 |
| Mountwood Ventures Limited | Construction | 2020 |
| Mova Consulting Limited | Financial services | 2018 |
| Movement Grips Limited | Administrative & support | 2021 |
| Moving Capital Limited | Information & communication | 2012 |
| MP Construction Limited | Construction | 2010 |
| MPD Group Limited | Professional & scientific | 2000 |
| MPH NO 1 Limited | Construction | 2017 |
| MPL Business Images LLP | | 2008 |
| MPL Interiors Ltd | Construction | 2019 |
| MR Boulton Consulting Ltd | Information & communication | 2025 |
| MR Corporations Ltd | Wholesale & retail | 2021 |
| Mrgpeople Limited | Extraterritorial | 2007 |
| Mrgsearch Limited | Extraterritorial | 2007 |
| Mrtmt Limited | Information & communication | 2023 |
| MRX Medical Limited | Health & social care | 2021 |
| MS Ovencare Limited | Administrative & support | 2009 |
| MSB Motor Company Limited | Wholesale & retail | 2009 |
| MSK Construction Consultants Limited | Professional & scientific | 2026 |
| MSL Aviation Limited | Education | 2016 |
| Msmith Electrical Services Limited | Construction | 2018 |
| Mtmt Limited | Professional & scientific | 2026 |
| Mudbrick Holdings Limited | Real estate | 2026 |
| Mulberry Design & Build (Oxshott) Limited | Construction | 2024 |
| Mulberry Home Care Services Limited | Health & social care | 2017 |
| Mulberry Homes (Construction Projects) Limited | Construction | 2016 |
| Mulberry Homes (Surrey) Limited | Real estate | 2015 |
| Mulberry Homes (Woking) Limited | Real estate | 2015 |
| Multi Service Direct Limited | Administrative & support | 2016 |
| Multi Service Ovencare Limited | Administrative & support | 2019 |
| Multi-Tech Computers (U.K.) Limited | Wholesale & retail | 1986 |
| Multiserve Innovations Ltd | Wholesale & retail | 2024 |
| Munks and ME Ltd | Manufacturing | 2017 |
| Munro Group Holdings Limited | Financial services | 2022 |
| Munro Nest Limited | Real estate | 2024 |
| Munster Management Company Limited | Real estate | 1991 |
| Murlough Sales Limited | Wholesale & retail | 2024 |
| Muse Agents LLP | | 2011 |
| Mutznutz Limited | Wholesale & retail | 2006 |
| MV Property Solutions Ltd | Construction | 2026 |
| Mwej Consulting Limited | Professional & scientific | 2024 |
| MWM Automotive Limited | Wholesale & retail | 2023 |
| MWM Estates Ltd | Real estate | 2018 |
| My Coaching Guru Ltd | Professional & scientific | 2018 |
| My Lives Limited | Other services | 2022 |
| My Media Network Ltd | Information & communication | 2026 |
| Myland Homes Limited | Real estate | 2016 |
| Mymedicaladvisor.Co.Uk Ltd | Professional & scientific | 2015 |
| MYTIME2BE Ltd | Health & social care | 2020 |
| N & a Payne Limited | Health & social care | 2005 |
| N & L Mcallister Limited | Other services | 2014 |
| N B Orthopaedic Clinic Limited | Health & social care | 2003 |
| N&A Couriers Ltd. | Transport & logistics | 2017 |
| N&R Consultancy Services Limited | Information & communication | 2013 |
| N. B. Holdings Limited | Real estate | 2000 |
| Nalan Athletica Ltd | Wholesale & retail | 2024 |
| Nanda's Catering LLP | | 2016 |
| Napier BOB Limited | Professional & scientific | 2019 |
| National Mining Ltd | Financial services | 2016 |
| National Services Ltd | Other services | 2019 |
| Natural Flames Limited | Wholesale & retail | 2011 |
| Nature by Heston | Health & social care | 2017 |
| Navigator UK Limited | Information & communication | 1996 |
| Navitas Consulting Ltd | Education | 2024 |
| NBE Associates Limited | Administrative & support | 2008 |
| NBM02 Limited | Real estate | 2003 |
| ND Designers Ltd | Professional & scientific | 2022 |
| NDA Regulatory Science Limited | Administrative & support | 1999 |
| Ndoto Limited | Administrative & support | 2018 |
| Nebulyx AI Limited | Information & communication | 2025 |
| Needlerock Services Limited | Professional & scientific | 2022 |
| Neel Builder Services Ltd | Construction | 2017 |
| Neeraj IT Consultancy Ltd | Information & communication | 2016 |
| Neil Richmond Limited | Real estate | 2010 |
| Neil Ward & Associates UK Limited | Administrative & support | 2015 |
| Neil Ward Investments Limited | Financial services | 2021 |
| Nemoris Group Ltd | Financial services | 2026 |
| Neo-Blu Ltd. | Wholesale & retail | 2015 |
| Neoinfinity Ltd | Information & communication | 2018 |
| Neos Opus Ltd | Construction | 2022 |
| Neptune Weybridge (Holdings) Ltd | Financial services | 2024 |
| Neptune Weybridge Ltd | Wholesale & retail | 2015 |
| Nestmatch Ltd | Information & communication | 2026 |
| Netherby & Terrace LLP | | 2024 |
| Netmera UK Ltd | Information & communication | 2013 |
| Networksupermarket.Com Limited | Wholesale & retail | 2012 |
| Neurosomatic Ltd | Other services | 2025 |
| Neutradvance Limited | Wholesale & retail | 2012 |
| Never Economy Again Limited | Information & communication | 2025 |
| New Build Contractors Ltd | Construction | 2021 |
| New Groove Ltd. | Manufacturing | 2007 |
| New Life Limited | Financial services | 2025 |
| New Penny Cleaning Limited | Administrative & support | 2012 |