| M & N Riccio Ltd | Other services | 2016 |
| M Form Limited | Construction | 2018 |
| M Y Accountancy Services (Essex) Limited | Professional & scientific | 2009 |
| M&H Commercial Repairs Ltd | Wholesale & retail | 2020 |
| M&N Fire Door Solutions Ltd | Construction | 2026 |
| M&Z Worldwide Ltd | Administrative & support | 2019 |
| M.R.C. Support Services Ltd | Construction | 2015 |
| Macalle Holdings Ltd | Financial services | 2020 |
| Macgerald Services Limited | Professional & scientific | 2006 |
| MAD Focus Productions Ltd | Professional & scientific | 2025 |
| Maddie Holdings Ltd | Construction | 2016 |
| Madwork Motorsport Ltd | Wholesale & retail | 2025 |
| Magnum Logistics Limited | Transport & logistics | 2009 |
| Maken Services Limited | Professional & scientific | 2019 |
| Maktoob Collection Ltd | Manufacturing | 2017 |
| Malvina Properties Limited | Construction | 2004 |
| Manex (Sand and Gravel) Limited | Real estate | 1982 |
| Manju & Co Stays Ltd | Hospitality | 2025 |
| Manns Heating & Bathrooms Ltd | Construction | 2023 |
| Mario Building & Plumbing Ltd | Construction | 2017 |
| Martin Enterprise India -UK Ltd | Mining & quarrying | 2025 |
| Mason Roofing Ltd | Construction | 2026 |
| Matrix Connections Ltd | Other services | 2023 |
| Matthew James Property Limited | Real estate | 2019 |
| Maug Detox and Addiction Services Limited | Health & social care | 2025 |
| Maywin Drive Residents Association Limited | Real estate | 2009 |
| MB Electrical & Controls Limited | Construction | 2022 |
| MBC Hires Ltd | Hospitality | 2023 |
| Mbcb Construction Ltd | Construction | 2021 |
| Mccarry's Ltd | Information & communication | 2018 |
| Mdl-Plus Limited | Public administration | 2023 |
| MDT Ceilings & Walls Limited | Construction | 2006 |
| MDT Glazing Ltd | Construction | 2026 |
| Med-X Health Mart Limited | Wholesale & retail | 2016 |
| Meedah Limited | Wholesale & retail | 2023 |
| Mental Health Momentum Ltd | Health & social care | 2024 |
| Mental Marketing Limited | Professional & scientific | 2008 |
| MF Express Limited | Wholesale & retail | 2025 |
| MG Property Rentals Ltd | Real estate | 2018 |
| MG Residence Ltd | Real estate | 2024 |
| MH UK Motors Ltd | Wholesale & retail | 2018 |
| MHM Publications Limited | Information & communication | 2024 |
| Mico Fellas Ltd | Other services | 2026 |
| Milano Beverage Ltd | Hospitality | 2024 |
| Milestone Legacy Ltd | Extraterritorial | 2023 |
| Millane Contract Services Ltd | Construction | 2002 |
| Millane Investments Holdings Limited | Real estate | 2021 |
| Millane London Ltd | Construction | 2016 |
| Millane Ltd | Construction | 2002 |
| Miller Motorsport Ltd | Construction | 2018 |
| Millieside Therapy & Coaching Ltd | Professional & scientific | 2020 |
| Mindorbit UK Ltd | Information & communication | 2025 |
| Minty Sky Ltd | Wholesale & retail | 2020 |
| Mj's Delicious Bakes Ltd | Hospitality | 2024 |
| MJB Project Services Limited | Administrative & support | 2016 |
| MJC 11 Limited | Transport & logistics | 2020 |
| MJH Ventilation Limited | Construction | 2017 |
| MK Consultancy Ltd | Professional & scientific | 2021 |
| MOE K2 Properties Limited | Real estate | 2021 |
| MON Chere Ltd | Manufacturing | 2020 |
| Montinest Ltd | Wholesale & retail | 2025 |
| Moonlight & White Limited | Information & communication | 2015 |
| Moonstone Massage and Spa Limited | Other services | 2023 |
| Motacam Limited | Extraterritorial | 2020 |
| Mothering Global Ltd | Information & communication | 2023 |
| Mouldsworth Estates Limited | Administrative & support | 2001 |
| Mount Aureol Healthcare Professionals Limited | Public administration | 2024 |
| MPF Renovations Ltd | Construction | 2026 |
| MPH Auto Services Limited | Wholesale & retail | 2023 |
| MSH Transport & Logistics Limited | Transport & logistics | 2021 |
| MTS Asset Holdings Limited | Real estate | 2026 |
| MTS Energy Limited | Extraterritorial | 2012 |
| MTS Estates Limited | Real estate | 2007 |
| MTS Mortgages Limited | Financial services | 2007 |
| Multiple Lifts Limited | Professional & scientific | 2019 |
| Muly Expedition Ltd | Transport & logistics | 2016 |
| Musa Mutawwir Limited | Information & communication | 2025 |
| MV HGV Ltd | Transport & logistics | 2023 |
| Mydolas Limited | Professional & scientific | 2018 |
| N C Trade Services Ltd | Construction | 2014 |
| N&D Building Ltd | Construction | 2013 |
| Nada Lambert Scrub Hats Limited | Manufacturing | 2021 |
| NADIR27 Ltd | Hospitality | 2025 |
| Nala Bake Ltd | Wholesale & retail | 2026 |
| Nandan Limited | Professional & scientific | 2023 |
| Nang Properties Ltd | Real estate | 2023 |
| Nang Rentals Ltd | Real estate | 2023 |
| Natasha John-Lewis Limited | Other services | 2023 |
| Navicena Ltd | Transport & logistics | 2015 |
| Neata Transport Ltd | Transport & logistics | 2016 |
| Nedflor Ltd | Wholesale & retail | 2024 |
| Nelbest London Ltd | Construction | 2024 |
| Nerkau Interiors Ltd | Construction | 2019 |
| Nero Construction Limited | Construction | 2024 |
| Nettverk (Global) Limited | Professional & scientific | 2017 |
| Newell Total Services Ltd | Construction | 2022 |
| Newham Cargo Ltd | Manufacturing | 2017 |
| Next Generation Windows Limited | Construction | 2017 |
| Next Level Prospects Ltd | Education | 2014 |
| NG Furniture Solution Ltd | Other services | 2018 |