| M Koshan Ltd | Wholesale & retail | 2025 |
| M LAL Heating Ltd | Construction | 2024 |
| M N Floor Training Limited | Construction | 2021 |
| M Nayyar Investments Limited | Real estate | 2020 |
| M Optical Limited | Wholesale & retail | 2017 |
| M P L Plastering Limited | Construction | 2005 |
| M P Meats Limited | Wholesale & retail | 2007 |
| M Pahal Ltd | Construction | 2016 |
| M R Hewitt Electrical Services Limited | Manufacturing | 2013 |
| M R Investment Properties Ltd | Real estate | 2022 |
| M S Afzal Properties Limited | Real estate | 2022 |
| M Sami Ltd | Wholesale & retail | 2026 |
| M Smith Reinforcement Limited | Construction | 2002 |
| M Traders Last Ltd | Information & communication | 2026 |
| M Zaviyar Enterprises Ltd | Wholesale & retail | 2026 |
| M&A.A Electrical Services Ltd | Construction | 2024 |
| M&B Logistic U.K. Ltd | Transport & logistics | 2020 |
| M&C Properties Midlands Ltd | Real estate | 2023 |
| M&Elv Ltd | Real estate | 2021 |
| M&Grigoras Ltd | Construction | 2024 |
| M&I Ultimate Glass Ltd | Construction | 2014 |
| M&J Design Engineers Ltd | Professional & scientific | 2019 |
| M&K 87 Ltd | Wholesale & retail | 2018 |
| M&K Freight Limited | Transport & logistics | 2018 |
| M&K Property Synergy Ltd | Real estate | 2025 |
| M&N Retail Ltd | Wholesale & retail | 2022 |
| M&O Motors Limited | Wholesale & retail | 2023 |
| M&R 985 Limited | Extraterritorial | 2005 |
| M&R Heating and Plumbing Limited | Construction | 2023 |
| M&R Transport Services Ltd | Transport & logistics | 2024 |
| M&S Care Solutions Ltd | Health & social care | 2016 |
| M&S Poultry Ltd | Wholesale & retail | 2026 |
| M. a. Davies (Wolverhampton) Limited | Construction | 2014 |
| M. E. Porter Publishing Ltd | Information & communication | 2025 |
| M. Foster Construction Limited | Construction | 1996 |
| M. P. S. Property Services Limited | Real estate | 2004 |
| M. Walton Electrical Limited | Construction | 2005 |
| M.A.J Construction Limited | Construction | 2024 |
| M.A.L Sisters Ltd | Other services | 2026 |
| M.A.X Building Construction Ltd | Construction | 2024 |
| M.B.E Management LLP | | 2021 |
| M.B.H. Builders Limited | Water & waste | 2004 |
| M.Byrne Conversions Ltd | Construction | 2020 |
| M.C. Windows & Building Services Ltd. | Construction | 2003 |
| M.D. Jeavons Limited | Professional & scientific | 2010 |
| M.D.G Rail Ltd | Administrative & support | 2014 |
| M.E. Footwear Ltd | Wholesale & retail | 2020 |
| M.E. Perrins Car & Light Commercial Vehicle Painting Limited | Manufacturing | 1979 |
| M.G.S.V Team Ltd | Manufacturing | 2018 |
| M.J.S. (Steels) Limited | | 1982 |
| M.L.R Homes Limited | Real estate | 2016 |
| M.Mathew Limited | Health & social care | 2022 |
| M.N. UGO Services Limited | Other services | 2016 |
| M.P.A. Services Limited | Health & social care | 1988 |
| M.R.M Furniture Ltd | Manufacturing | 2025 |
| M.S.A Delivery Services Ltd | Transport & logistics | 2025 |
| M1 Cuts Ltd | Other services | 2026 |
| M1 Systems Ltd | Wholesale & retail | 2026 |
| M155 HGV Ltd | Transport & logistics | 2011 |
| M2 Courier Services Ltd | Transport & logistics | 2025 |
| M3 Academy Audit & Consultancy Services Limited | Professional & scientific | 2016 |
| M3 Agency Manchester Limited | Professional & scientific | 2025 |
| M3 Communications Limited | Professional & scientific | 1999 |
| M3DIA City Ltd | Professional & scientific | 2025 |
| M6 Freight Ltd | Transport & logistics | 2022 |
| MA Distributors Ltd | Wholesale & retail | 2015 |
| MA Small Business Solution Ltd | Professional & scientific | 2025 |
| MA Tax Solutions Ltd | Professional & scientific | 2015 |
| MA Transit Ltd | Wholesale & retail | 2024 |
| MA UK Rentals Ltd | Hospitality | 2025 |
| Ma&P Homes Ltd | Real estate | 2026 |
| Maan Brothers Ltd | Real estate | 2023 |
| Maan Distribution Limited | Transport & logistics | 2025 |
| Maangat Transport Limited | Transport & logistics | 2020 |
| Maarifa-Tree Limited | Education | 2022 |
| Maast Services Ltd | Wholesale & retail | 2026 |
| MAB Rail Consultants Limited | Professional & scientific | 2024 |
| Mabika Business Limited | Extraterritorial | 2022 |
| Mably Ltd | Hospitality | 2024 |
| Mabuza Limited | Health & social care | 2023 |
| MAC Group Europe Ltd | Wholesale & retail | 2014 |
| MAC Mall Limited | Wholesale & retail | 2017 |
| Maca Contracts Limited | Construction | 2005 |
| Macario Entertainment Ltd | Hospitality | 2020 |
| Macderic Bakers Ltd | Manufacturing | 2024 |
| Mach Finance Ltd | Professional & scientific | 2024 |
| Machin Midlands Properties Limited | Real estate | 2025 |
| Mackays Consulting Ltd | Information & communication | 2017 |
| Macks Logistics Ltd | Transport & logistics | 2021 |
| Maclang Consulting Ltd | Professional & scientific | 2024 |
| Macro Minds Ltd | Information & communication | 2023 |
| Macrome Garage Limited | Manufacturing | 2012 |
| Macuga Property Ltd | Real estate | 2025 |
| MAD Plumbing Limited | Construction | 2026 |
| MAD Transport Group Ltd | Transport & logistics | 2026 |
| Madasales Ltd | Transport & logistics | 2025 |
| Madd Leisure Ltd | Hospitality | 2025 |
| Maddie Moos Ltd | Wholesale & retail | 2025 |
| Maddison Media Limited | Administrative & support | 2006 |
| Maddox Offices Limited | Real estate | 2021 |