| M&R QP Pharma Consultancy Limited | Professional & scientific | 2018 |
| M&S Alarms Ltd | Construction | 2016 |
| M&S Housing Ltd | Real estate | 2000 |
| M&S Operations Limited | Administrative & support | 2026 |
| M&S Solidarity Enterprise Ltd | Real estate | 2012 |
| M&T Luca Ltd | Manufacturing | 2019 |
| M&T Property Solutions Ltd | Real estate | 2023 |
| M&V Reeves Properties Ltd | Real estate | 2026 |
| M&W Electrical & Building Contractors Ltd | Construction | 2014 |
| M&Y (Regenda Partnership) Limited | Construction | 2003 |
| M&Y Maintenance & Construction Limited | Construction | 2000 |
| M-Power Services Limited | Administrative & support | 2015 |
| M-Rose Properties Ltd | Real estate | 2023 |
| M-Tech Integrated Ltd | Real estate | 2022 |
| M-Trans Europa Ltd | Transport & logistics | 2018 |
| M. & H. Joinery Ltd. | Construction | 1997 |
| M. Bresweth Electrical Ltd | Construction | 2016 |
| M. Lewis Electrical Limited | Construction | 2024 |
| M. W. Elliott Properties Limited | Real estate | 2023 |
| M.& Y.Property Management Limited | Households | 1971 |
| M.A. Logistics Limited | Transport & logistics | 2001 |
| M.A.C Inc Ltd | Administrative & support | 2019 |
| M.A.G. Financial Services Limited | Other services | 2006 |
| M.A.M GAS & Heating Services Ltd | Construction | 2025 |
| M.A.P Design Upvc & Aluminium Limited | Construction | 2021 |
| M.Augustyniak Transport Ltd | Wholesale & retail | 2016 |
| M.B.E. Construction Limited | Construction | 2007 |
| M.C. Collection Ltd | Other services | 2020 |
| M.Christie Logistics Ltd | Transport & logistics | 2019 |
| M.Cmok Transport Ltd | Transport & logistics | 2016 |
| M.Douglas Driveways & Patios Limited | Administrative & support | 2021 |
| M.E.G.Site Management Ltd | Construction | 2015 |
| M.E.J Telecoms Ltd | Other services | 2019 |
| M.E.R. Builders Ltd | Construction | 2018 |
| M.E.S. Nationwide Services Limited | Manufacturing | 2003 |
| M.H. Detrick Company Ltd | Professional & scientific | 2008 |
| M.H. Smith Ltd | Professional & scientific | 2009 |
| M.Hristov Ltd | Transport & logistics | 2026 |
| M.I Fire & Security Systems Limited | Administrative & support | 2025 |
| M.I.A.R Company Ltd | Hospitality | 2022 |
| M.I.Cal.Instruments Limited | Manufacturing | 2000 |
| M.J. Lavin Plant and Machinery Limited | Administrative & support | 2000 |
| M.J.B. Renewables Limited | Construction | 2025 |
| M.Jablonski Ltd | Transport & logistics | 2018 |
| M.K Massage Ltd | Other services | 2015 |
| M.K Properties(Uk) Ltd | Real estate | 2019 |
| M.K.S Solutions U.K Ltd | Construction | 2017 |
| M.L.P Settle Cars Limited | Transport & logistics | 2014 |
| M.P Build Maintain Limited | Construction | 2025 |
| M.P Building Management Ltd | Real estate | 2022 |
| M.P Plumbing and Heating Solutions Ltd | Construction | 2016 |
| M.R. Bloor & Co Limited | Financial services | 2003 |
| M.Rooney Rail Engineering Ltd | Transport & logistics | 2025 |
| M.S Property Management Group Ltd | Professional & scientific | 2016 |
| M.S. Ngum Holdings Ltd | Financial services | 2026 |
| M.S.I Electrical Ltd | Construction | 2014 |
| M.T Boxing Ltd | Arts & recreation | 2024 |
| M.T.L Scaffolding Solutions Ltd | Construction | 2021 |
| M.T.W Commercials Ltd | Wholesale & retail | 2025 |
| M.V.S. Ltd | Health & social care | 2026 |
| M/Lk Executive Search Ltd | Administrative & support | 2022 |
| M0THER HQ Ltd | Wholesale & retail | 2016 |
| M1 Developments Ltd | Construction | 2022 |
| M1 Nail & Hair Allerton Ltd | Other services | 2024 |
| M12 RLP Limited | Financial services | 2017 |
| M140I Limited | Transport & logistics | 2025 |
| M2 Plumbing & Heating Ltd | Construction | 2026 |
| M2K Solutions Group Limited | Professional & scientific | 2026 |
| M2MDATA (UK) Limited | Professional & scientific | 2012 |
| M3 Properties (UK) Limited | Real estate | 2001 |
| M50 Flooring Ltd | Wholesale & retail | 2008 |
| M56 Ltd | Professional & scientific | 2023 |
| M57 Car Sales Ltd | Wholesale & retail | 2026 |
| M6 Autos Ltd | Financial services | 2022 |
| M6 Garage Limited | Financial services | 2025 |
| M6 Trailer Curtain Services Ltd | Manufacturing | 2021 |
| M62 Limited | Administrative & support | 2018 |
| M7 Services Limited | Construction | 2018 |
| M@T Caterers Limited | Hospitality | 2024 |
| MA & SC Sinclair Trading Limited | Professional & scientific | 2021 |
| MA Boyles Eatery & Alehouse Ltd | Hospitality | 2014 |
| MA Build & Renovation Ltd | Construction | 2025 |
| MA Changezi Ltd | Wholesale & retail | 2025 |
| MA Chere Motorcars Ltd | Wholesale & retail | 2024 |
| MA Davies Holdings Ltd | Construction | 2024 |
| MA Top Roofing Ltd | Construction | 2025 |
| Ma'Dudes Cleaning Services Limited | Administrative & support | 2020 |
| Ma-Legal Group Limited | Professional & scientific | 2025 |
| MA1 Limited | Real estate | 2025 |
| MAA Financial Solutions Ltd | Professional & scientific | 2025 |
| Maabapu@ Ltd | Wholesale & retail | 2024 |
| Maakah Halal Meats Limited | Wholesale & retail | 2018 |
| Maan Brothers Building Ltd | Construction | 2024 |
| Maanra Ltd | Real estate | 2012 |
| MAB Property Management Limited | Real estate | 2022 |
| MAB Suites 1 Limited | Real estate | 2024 |
| MAB Suites CW 14 Limited | Real estate | 2023 |
| MAB Suites CW 15 Limited | Real estate | 2023 |
| MAB Suites CW I Limited | Real estate | 2022 |
| MAB Suites CW II Limited | Real estate | 2022 |