| M&N Global Foods Limited | Wholesale & retail | 2023 |
| M&N Joinery Ltd | Manufacturing | 2021 |
| M&P Care PVT Ltd | Health & social care | 2019 |
| M&S Estates Ltd | Real estate | 2025 |
| M&S Realty 2 Ltd | Real estate | 2023 |
| M&S Realty Ltd | Real estate | 2017 |
| M&S Seller Ltd | Wholesale & retail | 2025 |
| M&S Solutions Limited | Information & communication | 2011 |
| M&T Transport Ltd | Transport & logistics | 2018 |
| M-Z Trans Ltd | Transport & logistics | 2017 |
| M. E Optical Limited | Health & social care | 2009 |
| M. J. Anderson Ltd | Professional & scientific | 2000 |
| M. J. Bedford Ltd | Construction | 2008 |
| M.A.S-71 Ltd | Health & social care | 2022 |
| M.A.Saleem Investment Ltd | Real estate | 2023 |
| M.A.Saleem Ltd | Health & social care | 2022 |
| M.B.F Pets Ltd | Wholesale & retail | 2025 |
| M.C. Integ Limited | Construction | 1983 |
| M.D.V. Trans Limited | Transport & logistics | 2018 |
| M.Di Domenico Carpets & Flooring Ltd | Construction | 2019 |
| M.E.G.A Ministerio Evangelico Geracao DO Amor Ltd | Other services | 2019 |
| M.F. Hansen & Co. Limited | Construction | 1975 |
| M.H.S. Farms Limited | Agriculture & fishing | 1996 |
| M.I.M.E Group Ltd | Administrative & support | 2014 |
| M.J. Farley Communications Limited | Information & communication | 2005 |
| M.K Rauner Car Parts Import Export Ltd. | Wholesale & retail | 2021 |
| M.K. Barud Ltd | Construction | 2017 |
| M.L. Worsdall & SON Limited | Transport & logistics | 2008 |
| M.M Trans Services Ltd | Transport & logistics | 2025 |
| M.Mustafa Ltd | Transport & logistics | 2021 |
| M.R. Topham Limited | Agriculture & fishing | 1998 |
| M.R.Contractors Limited | Construction | 2024 |
| M.Visuals Limited | Information & communication | 2022 |
| M18PRODUCTION Ltd | Information & communication | 2018 |
| M19 Production Ltd | Information & communication | 2018 |
| M2 Consultancy Limited | Professional & scientific | 2022 |
| M2S Cars & Vans Ltd | Wholesale & retail | 2024 |
| M8M Logistics Ltd | Transport & logistics | 2023 |
| MA Foods Peterborough Ltd | Wholesale & retail | 2024 |
| MA Grandé Motors Ltd | Wholesale & retail | 2025 |
| MA Imperial Homes Limited | Real estate | 2025 |
| MA Plant Ltd | Wholesale & retail | 2021 |
| MAA Global Ltd | Real estate | 2023 |
| MAA Group Holdings Ltd | Professional & scientific | 2021 |
| MAA Investments Ltd | Real estate | 2016 |
| Maabiz Group Ltd | Wholesale & retail | 2021 |
| Maac Logistics Ltd | Transport & logistics | 2019 |
| Maande Ltd | Real estate | 2025 |
| Maani International Ltd | Transport & logistics | 2024 |
| Maaz Properties Ltd | Real estate | 2020 |
| Mabask Ltd | Other services | 2019 |
| Macade Golf Ltd | Wholesale & retail | 2026 |
| Maccoll Brother Investments Ltd | Real estate | 2022 |
| Mace Services Ltd | Administrative & support | 2018 |
| Macgregor MAY Ltd | Real estate | 2023 |
| Mach Transport Ltd | Transport & logistics | 2020 |
| Machinefix Ltd. | Administrative & support | 2010 |
| Machiningworks Limited | Manufacturing | 2005 |
| Macinvest Holding Ltd | Financial services | 2023 |
| Mack Contracting Services Ltd | Professional & scientific | 2024 |
| Mack Investment Ventures Ltd | Financial services | 2025 |
| Maclor Solutions Ltd | Professional & scientific | 2021 |
| MAD Garage Ltd | Wholesale & retail | 2025 |
| MAD Mario's Garage Ltd | Wholesale & retail | 2017 |
| MAD Wasp Productions Ltd | Manufacturing | 2017 |
| Mada&Edi Trans Ltd | Transport & logistics | 2025 |
| Madamm Vision LLP | | 2025 |
| Madani Limited | Health & social care | 2011 |
| Madani Trading Limited | Transport & logistics | 2026 |
| Madcaps and Mini Madcaps Limited | Health & social care | 2026 |
| Madcow Brand Limited | Manufacturing | 2018 |
| Madden Installations Limited | Construction | 2021 |
| Madden Property Lets Ltd | Real estate | 2025 |
| Maddocks Works Ltd | Professional & scientific | 2025 |
| Maddy Turley Consulting Limited | Professional & scientific | 2014 |
| Made 4 Care Ltd | Health & social care | 2024 |
| Made Clear Ltd | Financial services | 2014 |
| Madewithwanderlust Ltd | Administrative & support | 2026 |
| Madina Curry House Ltd | Hospitality | 2023 |
| Madina Foods Limited | Wholesale & retail | 2015 |
| Madina Grill (Cambs) Ltd | Hospitality | 2017 |
| Madion Limited | Construction | 2025 |
| Madn Ltd | Transport & logistics | 2025 |
| Maeaura Luxe Limited | Professional & scientific | 2025 |
| Maes Peterborough Ltd | Transport & logistics | 2024 |
| Maes Transport Ltd | Transport & logistics | 2021 |
| Mafe Martial Arts for Everyone Ltd | Education | 2023 |
| Maflor Ltd | Transport & logistics | 2022 |
| Mafyoo Limited | Information & communication | 2013 |
| MAG Distribution Ltd | Wholesale & retail | 2023 |
| Maga NW Ltd | Wholesale & retail | 2016 |
| Magazine World Ltd | Wholesale & retail | 2024 |
| Magic Beans Trading Limited | Wholesale & retail | 2020 |
| Magic Broom Cleaning Service Limited | Administrative & support | 2019 |
| Magic Brush Beauty Salon Limited | Other services | 2021 |
| Magic Cat Luster Ltd | Wholesale & retail | 2024 |
| Magic Clps Ltd | Manufacturing | 2020 |
| Magic Mack Ltd | Transport & logistics | 2023 |
| Magic Roofing Ltd | Construction | 2016 |
| Magic Tattoo Ltd | Other services | 2017 |