| M H Pro Tools Ltd | Wholesale & retail | 2019 |
| M Humphreys Transport Limited | Transport & logistics | 2005 |
| M Hyde Roofing and Cladding Limited | Construction | 2015 |
| M I Coaching Ltd | Arts & recreation | 2023 |
| M J Speck Joinery Limited | Construction | 2004 |
| M K Plasterers Ltd | Construction | 2011 |
| M Kirkbride Ltd | Wholesale & retail | 2024 |
| M L Surfacing Solutions Ltd | Administrative & support | 2013 |
| M M S Maintenance Limited | Construction | 2009 |
| M Majid TM Ltd | Public administration | 2024 |
| M Mateo Ltd | Transport & logistics | 2020 |
| M MEE C.I.C. | Education | 2019 |
| M P Cargo Limited | Transport & logistics | 2014 |
| M P Owen Building Services Limited | Construction | 2020 |
| M P R Services Ltd | Professional & scientific | 2001 |
| M P Water Treatment Services Ltd | Water & waste | 2021 |
| M R Landscaping Ltd | Real estate | 2022 |
| M R Poultry Ltd | Construction | 2018 |
| M R Taylor (Builders) Limited | Construction | 2004 |
| M S Tunney Ltd | Real estate | 2024 |
| M Shillito Limited | Construction | 2016 |
| M Sibanda Care Limited | Health & social care | 2026 |
| M Siddons Limited | Construction | 2025 |
| M Smith Rail Ltd | Construction | 2016 |
| M SVN Capital Ltd | Financial services | 2025 |
| M T R Properties & Developments Ltd | Real estate | 2025 |
| M W Windows Ltd | Manufacturing | 2023 |
| M Walker Engineering Ltd | Professional & scientific | 2019 |
| M Wilson Accountants Limited | Professional & scientific | 2010 |
| M&A Autobody Repair Ltd | Wholesale & retail | 2025 |
| M&A Spotless Solutions Ltd | Administrative & support | 2026 |
| M&A Total Properties Limited | Real estate | 2025 |
| M&B (Italia) Limited | Hospitality | 2016 |
| M&B Italia Properties Limited | Real estate | 2017 |
| M&B Logistical Solutions Limited | Transport & logistics | 2018 |
| M&C Deliveries Ltd | Transport & logistics | 2021 |
| M&C Store Developments Ltd | Administrative & support | 2019 |
| M&D 87 Limited | Transport & logistics | 2023 |
| M&D Foundations Eastern Limited | Construction | 2014 |
| M&D Transport Solutions Ltd | Transport & logistics | 2025 |
| M&F Roofing Ltd | Construction | 2025 |
| M&G Service Station Ltd | Wholesale & retail | 2015 |
| M&J Speed Ltd | Manufacturing | 2016 |
| M&M Capital Holdings Ltd | Financial services | 2026 |
| M&M Delivery Ltd | Transport & logistics | 2025 |
| M&M Freight and Fitness Limited | Transport & logistics | 2025 |
| M&M Global Enterprises Ltd | Wholesale & retail | 2025 |
| M&M Logisticstransport Ltd | Transport & logistics | 2019 |
| M&M Utilities Limited | Construction | 2018 |
| M&P Training Ltd | Education | 2026 |
| M&R Contract Services Ltd | Construction | 2020 |
| M&S Leisure Property UK Ltd | Hospitality | 2025 |
| M&S Medics Limited | Health & social care | 2021 |
| M&S Ozcelik Limited | Real estate | 2024 |
| M&S Salvage Limited | Wholesale & retail | 2026 |
| M&T Haulage Ltd | Transport & logistics | 2018 |
| M&X Barbers Limited | Other services | 2022 |
| M-B Property & Investments Limited | Real estate | 2025 |
| M-Sax Ltd | Arts & recreation | 2025 |
| M-Tec Projects & Services Limited | Construction | 2014 |
| M. & D. Drilling Company Limited | Construction | 1997 |
| M. Higgins Limited | Agriculture & fishing | 1979 |
| M. J. Harvey Limited | Construction | 2005 |
| M.A.P Construction and Home Improvements Limited | Construction | 2022 |
| M.A.S Retail Management Ltd | Real estate | 2025 |
| M.C.I. Developments Limited | Construction | 2011 |
| M.E. Utilities Ltd | Construction | 2024 |
| M.E.C. Safe Limited | Professional & scientific | 2000 |
| M.E.C. Signs Limited | Manufacturing | 1962 |
| M.E.E.P Installations Ltd | Construction | 2023 |
| M.F.K Transport Ltd | Transport & logistics | 2023 |
| M.G. Builders (Doncaster) Ltd | Construction | 2017 |
| M.Haigh Building Services Ltd | Construction | 2022 |
| M.J. Harriman Limited | Information & communication | 2013 |
| M.K. Contract Solutions Ltd | Transport & logistics | 2025 |
| M.K.W. Properties Ltd | Real estate | 2000 |
| M.M.F Investments Ltd | Real estate | 2025 |
| M.S.Transportation Ltd | Transport & logistics | 2022 |
| M.Sullivan Property Maintenance Ltd | Construction | 2025 |
| M.Swann TM Ltd | Public administration | 2025 |
| M.T. Rigging Solutions Limited | Information & communication | 2018 |
| M18 Junction 4 Storage Limited | Other services | 2022 |
| M3J Limited | Education | 2013 |
| MA Transport Solutions Ltd | Transport & logistics | 2013 |
| Maat Capital Ltd | Extraterritorial | 2023 |
| Maazoya Medical Limited | Health & social care | 2011 |
| Mabcloding Ltd | Wholesale & retail | 2024 |
| Mabley Ltd. | Wholesale & retail | 2026 |
| Mabz Ltd | Extraterritorial | 2013 |
| MAC Delivery Ltd | Transport & logistics | 2025 |
| MAC Marketing Ltd | Professional & scientific | 2022 |
| MAC PM Derby Limited | Professional & scientific | 2025 |
| MAC Pro Build Limited | Construction | 2024 |
| MAC Properties Doncaster Limited | Real estate | 2020 |
| MAC Tools Doncaster Limited | Wholesale & retail | 2012 |
| MAC86 Ltd | Transport & logistics | 2018 |
| Macau Logistics Ltd | Transport & logistics | 2019 |
| Macauley Gibb Real Estate Ltd | Administrative & support | 2017 |
| Macauley Gibb Realty (Estates) Ltd | Real estate | 2023 |
| Macauley Gibb Realty Ltd | Real estate | 2023 |