| M Staniland Travel Limited | Administrative & support | 2014 |
| M T Traffic Safety Ltd | Construction | 2026 |
| M Tawa Express Limited | Hospitality | 2019 |
| M Texh Ltd | Wholesale & retail | 2025 |
| M Veitch Limited | Real estate | 2020 |
| M W H Estates Ltd | Water & waste | 2022 |
| M W Lane Developments Limited | Construction | 2003 |
| M W Projects Ltd | Construction | 2021 |
| M W Richardson Ltd | Administrative & support | 2025 |
| M White (Skips) Limited | Water & waste | 2013 |
| M White Builders Limited | Construction | 2013 |
| M Woolhouse Builders Limited | Construction | 1990 |
| M Worth Auto Repairs Ltd | Wholesale & retail | 2014 |
| M Worth Autos Ltd | Wholesale & retail | 2013 |
| M Y Construction(Yorkshire) Limited | Construction | 2025 |
| M Y Drainage & Groundworks Limited | Construction | 2012 |
| M& N Eco Car Wash Limited | Transport & logistics | 2019 |
| M&A Construction & Development Limited | Construction | 2024 |
| M&A Hair and Beauty Ltd | Other services | 2026 |
| M&A Hair Shop Ltd | Other services | 2026 |
| M&A Ltd | Wholesale & retail | 2023 |
| M&A Signs and Print Ltd | Manufacturing | 2024 |
| M&C Distributors Ltd | Wholesale & retail | 2020 |
| M&C Ultrasound Limited | Health & social care | 2025 |
| M&F Services UK Limited | Wholesale & retail | 2009 |
| M&G Elite Ventures Ltd | Households | 2024 |
| M&H Commerce Ltd | Wholesale & retail | 2026 |
| M&J Group of Companies Ltd | Wholesale & retail | 2025 |
| M&J Morris Contractors Ltd | Transport & logistics | 2025 |
| M&J Pido Properties SPV Limited | Real estate | 2017 |
| M&K Homes Ltd | Real estate | 2025 |
| M&K Luxe Properties Limited | Real estate | 2024 |
| M&L Facade Ltd | Construction | 2019 |
| M&M Accounting Ltd | Professional & scientific | 2024 |
| M&M Leisure Ltd | Hospitality | 2024 |
| M&M Stores Ltd | Wholesale & retail | 2016 |
| M&N Medics Limited | Health & social care | 2022 |
| M&P Caswell Limited | Hospitality | 2012 |
| M&P Holdings Limited | Financial services | 2019 |
| M&P Ventures Ltd | Administrative & support | 2024 |
| M&R Custom Made Ltd | Manufacturing | 2020 |
| M&S Medical Consulting Ltd | Health & social care | 2025 |
| M&S PUB Management Ltd | Administrative & support | 2025 |
| M&T Chahal Ltd | Transport & logistics | 2024 |
| M&Z Food Ltd | Hospitality | 2025 |
| M'Flys Logistic Ltd | Transport & logistics | 2021 |
| M-Eat Restaurants Ltd | Hospitality | 2024 |
| M-Fibre Solutions Ltd | Information & communication | 2022 |
| M-Line Travel Ltd | Transport & logistics | 2024 |
| M. & T. Welding Systems Limited | Manufacturing | 1989 |
| M. and B. Cycles (Dronfield) Limited | Real estate | 1979 |
| M. Bailey Decorating Services Ltd | Construction | 2009 |
| M. Carr (Sheffield) Limited | Construction | 1977 |
| M. I. Services (Retail) Limited | Construction | 2014 |
| M. Jaffer Ltd | Health & social care | 2020 |
| M. M. Bell & Sons (Holdings) Limited | Financial services | 2012 |
| M. M. Bell & Sons Limited | Manufacturing | 1998 |
| M. R. Machine Knives Ltd | Manufacturing | 2008 |
| M. Rilo Ltd | Health & social care | 2012 |
| M. Seed Properties Group Ltd | Real estate | 2026 |
| M.A Electrical Contractor Ltd | Construction | 2019 |
| M.A.E Hope Wealth Management Ltd | Financial services | 2023 |
| M.A.F. Holdings Limited | Real estate | 2016 |
| M.A.H Ridall Ltd | Information & communication | 2016 |
| M.A.T Construction Group Ltd | Construction | 2026 |
| M.A.T.S Construction Ltd | Construction | 2022 |
| M.Aura My Signature Ltd | Wholesale & retail | 2025 |
| M.E.G Hair Studio Ltd. | Other services | 2018 |
| M.E.N Engineering Services Ltd | Professional & scientific | 2026 |
| M.F. Hire Limited | Administrative & support | 1978 |
| M.F.H. Contract Engineering Services (Leicester) Limited | Professional & scientific | 1979 |
| M.F.H. Contract Engineering Services Limited | Manufacturing | 1975 |
| M.F.H. Engineering (Holdings) Limited | Professional & scientific | 1978 |
| M.G.L. Management & Engineering Services Limited | Professional & scientific | 1993 |
| M.H.A Property Holdings Ltd | Real estate | 2019 |
| M.H.A. (Eyeco) Limited | Wholesale & retail | 2017 |
| M.H.A. (Healthco) Limited | Wholesale & retail | 2017 |
| M.H.G (Supplies) Holdings Limited | Financial services | 2024 |
| M.H.G. (Supplies) Limited | Wholesale & retail | 2001 |
| M.I. Vision Limited | Professional & scientific | 2011 |
| M.Ita Engineering Ltd | Administrative & support | 2023 |
| M.J Cleaning Services Ltd | Administrative & support | 2025 |
| M.J. & B. Plastering Limited | Construction | 2002 |
| M.J.Buz.Electrical Limited | Construction | 2022 |
| M.J.G(Management)Limited | Extraterritorial | 1968 |
| M.K. Floortec Services Ltd | Administrative & support | 2010 |
| M.K.D. Properties Limited | Real estate | 2000 |
| M.K.O. Abbeydale Limited | Health & social care | 1998 |
| M.Kwame Limited | Construction | 2018 |
| M.M Cellar Ltd | Wholesale & retail | 2023 |
| M.M. Design Limited | Professional & scientific | 2012 |
| M.M. Graff Ltd | Real estate | 2024 |
| M.Mehboob Limited | Wholesale & retail | 2025 |
| M.R Croke Limited | Other services | 2023 |
| M.R. Brickwork Solutions Ltd | Construction | 2026 |
| M.R. Flooring Ltd | Construction | 2012 |
| M.R.L Services Ltd | Construction | 2024 |
| M.S. Shirts Box Company Limited | Other services | 1986 |
| M.S. Sibley Associates Limited | Construction | 2019 |
| M.W.R. Radatz Limited | Health & social care | 2009 |