| Milton Fish & Chips (Sittingbourne) Ltd | Hospitality | 2025 |
| Milton Heating Solutions Ltd | Construction | 2018 |
| Milton Miles Ltd | Arts & recreation | 2023 |
| Milton Pipes Limited | Real estate | 1963 |
| Mindara Wellbeing Ltd | Health & social care | 2026 |
| Mindful Moon Ltd | Wholesale & retail | 2025 |
| Mindgeeks Ltd | Health & social care | 2023 |
| Minerva Scientific Limited | Professional & scientific | 2001 |
| Minibus Coach Travel Limited | Transport & logistics | 2015 |
| Minister-Power Limited | Professional & scientific | 2012 |
| Mint Assets Ltd | Real estate | 2018 |
| Mint Buildings Ltd | Real estate | 2021 |
| Mint Command Ltd | Professional & scientific | 2026 |
| Mirabelle Properties Limited | Real estate | 2019 |
| MISSION2CONDITION Limited | Arts & recreation | 2018 |
| Mitchell Atkinson Ltd | Financial services | 2019 |
| Mitec Fire and Security Ltd | Other services | 2020 |
| Mitec Safety Management Limited | Public administration | 2015 |
| MJ Bourke Associates Limited | Professional & scientific | 2025 |
| MJB Architects Limited | Professional & scientific | 2022 |
| MJM Consult (UK) Limited | Professional & scientific | 2014 |
| Mjoo Service Ltd | Administrative & support | 2023 |
| MK Quartz & Granite Worktops Ltd | Manufacturing | 2021 |
| MKB Consulting Ltd | Professional & scientific | 2019 |
| ML Property Maintenance Services Ltd | Construction | 2004 |
| Mldt Properties Ltd | Real estate | 2017 |
| Mlisana Limited | Health & social care | 2022 |
| Mls-Protection Ltd | Administrative & support | 2018 |
| MM Trans-Training Limited | Transport & logistics | 2013 |
| MNE Environmental Ltd | Professional & scientific | 2021 |
| Mobart Cladding Ltd | Construction | 2025 |
| Mode Resources Limited | Administrative & support | 2019 |
| Model World Limited | Wholesale & retail | 2003 |
| Modern Forge Construction Ltd | Construction | 2025 |
| Modern Lighting Solutions Ltd | Wholesale & retail | 2010 |
| Modern Vintage Living Ltd | Wholesale & retail | 2024 |
| Modular Pipe Organ Systems Limited | Manufacturing | 2008 |
| Moesha Tate Limited | Information & communication | 2015 |
| Molly's Events Limited | Administrative & support | 2018 |
| Molo Trans 91 Ltd | Wholesale & retail | 2018 |
| Monada Touch Ltd | Administrative & support | 2024 |
| Money Box Ltd | Construction | 2015 |
| Monolith London Ltd | Financial services | 2026 |
| Monolith Propco Ltd | Real estate | 2026 |
| Montego's Trading Ltd | Wholesale & retail | 2019 |
| Montville Business Services Limited | Administrative & support | 2025 |
| Moore Plumbing & Heating Ltd | Construction | 2019 |
| Mopelola Limited | Health & social care | 2022 |
| Moregame Ltd | Professional & scientific | 2025 |
| Morning Club Ltd | Extraterritorial | 2023 |
| Morningside Care Services Ltd | Health & social care | 2025 |
| Morso & Pinner Ltd | Wholesale & retail | 2024 |
| Mortgage and More Limited | Financial services | 2007 |
| Motorsport at the Palace Ltd. | Arts & recreation | 2009 |
| Move on NOW Limited | Real estate | 2002 |
| MP Properties Kent Limited | Real estate | 2023 |
| MPC Precast Limited | Financial services | 2010 |
| MPW Associates Ltd | Professional & scientific | 2009 |
| MR EV UK Ltd | Information & communication | 2024 |
| MR S Barnes Ltd | Financial services | 2023 |
| MRACCOUNTANT4ALL Ltd | Professional & scientific | 2024 |
| MS (Kent) Services Limited | Construction | 2024 |
| MSA Supply Limited | Administrative & support | 2025 |
| MSI Transport Limited | Transport & logistics | 2026 |
| MSK Trade Ltd | Construction | 2017 |
| Mstp Consulting Limited | Other services | 2010 |
| Mudaka Properties Limited | Real estate | 2023 |
| Mudze Core Solutions Ltd | Administrative & support | 2020 |
| Mulan Property Services and Management Limited | Real estate | 2018 |
| Munehisa & Co Limited | Financial services | 2022 |
| Munehisa Labs Ltd | Information & communication | 2026 |
| Munsgore Farm Stables Ltd | Agriculture & fishing | 2018 |
| Musique-Cordiale Services Ltd. | Arts & recreation | 2015 |
| Musumali Properties Ltd | Real estate | 2024 |
| Mutual Holdings Limited | Financial services | 2022 |
| Muzafry Homes Limited | Real estate | 2024 |
| MVC1 Limited | Financial services | 2023 |
| MVV Environment Ridham Limited | Energy | 2012 |
| MW IT Services (Hospitality) Ltd | Information & communication | 2017 |
| My Chocolate Shop Limited | Wholesale & retail | 2021 |
| My Little Dreamer Home Ltd | Wholesale & retail | 2026 |
| My New Start Ltd | Health & social care | 2026 |
| MYM Group Ltd | Construction | 2025 |
| Myzambia Myafrica Limited | Information & communication | 2017 |
| Mzk.Uk.Trans Ltd | Transport & logistics | 2020 |
| N Johnston Limited | Professional & scientific | 2019 |
| N. L. Services Garage Ltd | Wholesale & retail | 2017 |
| N33RKA Ltd | Transport & logistics | 2024 |
| Nadir Indian Cuisine Ltd | Hospitality | 2018 |
| Nakar Design & Consultancy Ltd | Professional & scientific | 2024 |
| Nambs Services Limited | Health & social care | 2020 |
| Namsu Pilates Studio Ltd | Arts & recreation | 2025 |
| Nark Properties Limited | Real estate | 2025 |
| Natalie Mead Consultancy Ltd | Professional & scientific | 2018 |
| National Consultants Ltd | Construction | 2024 |
| Nationwide Industrial Services Ltd | Manufacturing | 2020 |
| Naturally Salon Rental Ltd | Other services | 2026 |
| Naturally U Ltd | Other services | 2017 |
| Natures Soul Ltd | Administrative & support | 2019 |
| Natzac Ltd | Real estate | 2024 |