| M&N Groundworks Ltd | Construction | 2022 |
| M&N Landholdings Ltd | Financial services | 2024 |
| M&O&N Services Ltd | Construction | 2021 |
| M&R Executive Ltd | Transport & logistics | 2022 |
| M&S Future Property Ltd | Real estate | 2025 |
| M&S Health Ltd | Health & social care | 2020 |
| M&S Repair Ltd | Wholesale & retail | 2024 |
| M&S Transport Services Ltd | Transport & logistics | 2021 |
| M&S Travel Ltd | Transport & logistics | 2025 |
| M&W Trading Limited | Hospitality | 2018 |
| M&Zee Ltd | Construction | 2025 |
| M-A Cotea Limited | Wholesale & retail | 2024 |
| M. D. D. Services (UK) Limited | Administrative & support | 2014 |
| M. O'Malley Electrical Services Limited | Construction | 2008 |
| M.A Financial Consulting Svcs Ltd | Real estate | 2021 |
| M.A Goflow Plumbing and GAS Engineering Limited | Construction | 2026 |
| M.A Whitestone Limited | Construction | 2025 |
| M.A.È Eatlovelisten Limited | Hospitality | 2018 |
| M.B.P Technical Services Limited | Professional & scientific | 2011 |
| M.D.C. Exports Limited | Professional & scientific | 1985 |
| M.D.D. Buildings Limited | Real estate | 2018 |
| M.E. VLC Ltd | Construction | 2026 |
| M.G. Design & Management Limited | Arts & recreation | 2007 |
| M.H Jewellers Ltd | Wholesale & retail | 2021 |
| M.Hussain Consulting Services Ltd | Information & communication | 2016 |
| M.I Capital Investments Ltd | Construction | 2020 |
| M.K BRO Properties Ltd | Real estate | 2024 |
| M.M.Dattani Property Group Ltd | Real estate | 2025 |
| M.S Groundworkers Ltd | Construction | 2025 |
| M.S N Utilities Ltd | Construction | 2024 |
| M.V’S Plumbing&Heating Ltd | Construction | 2023 |
| M1 Alignments Ltd | Wholesale & retail | 2025 |
| M1 Autos Ltd | Wholesale & retail | 2018 |
| M1 Tyres Ltd | Wholesale & retail | 2024 |
| M25 Moto Ltd | Wholesale & retail | 2022 |
| M2H Group Ltd | Transport & logistics | 2019 |
| M2RD Limited | Hospitality | 2022 |
| M4I Partners Ltd | Health & social care | 2008 |
| MA Car Supermarket Ltd | Wholesale & retail | 2024 |
| MA Construction (South) Limited | Construction | 2024 |
| MA Law Consultancy Ltd | Professional & scientific | 2026 |
| MA Luton Properties Ltd | Real estate | 2025 |
| MA Tech Services Limited | Information & communication | 2025 |
| MA Transport Group Ltd | Transport & logistics | 2020 |
| Ma&Aa Co Ltd | Administrative & support | 2025 |
| Ma&Rox Logistics Ltd | Transport & logistics | 2025 |
| Ma&S Limited | Other services | 2021 |
| MAA Accommodations Ltd | Real estate | 2020 |
| Maaloos UK Ltd | Hospitality | 2023 |
| Maani & Co Ltd | Wholesale & retail | 2025 |
| Maati Tech Technnology Solutions Ltd | Information & communication | 2017 |
| Maazz Ltd | Wholesale & retail | 2022 |
| MAB & Sheys Ltd | Wholesale & retail | 2026 |
| MAB Autos Ltd | Wholesale & retail | 2020 |
| MAC Archie Flooring Ltd | Wholesale & retail | 2025 |
| MAC Glen Plastering Ltd | Construction | 2018 |
| MAC Health Ltd | Education | 2024 |
| MAC LY Limited | Hospitality | 2008 |
| Macagen Chuab Ltd | Wholesale & retail | 2025 |
| Macaj Ltd | Real estate | 2026 |
| Macdonald Ventures Limited | Administrative & support | 2021 |
| Mace Ductwork Limited | Construction | 2006 |
| Machine TEK Limited | Professional & scientific | 1996 |
| Machinery Movement Training Ltd | Education | 2021 |
| Machinery-Movers Ltd | Education | 2024 |
| Machins Solicitors LLP | | 2010 |
| Machx Tuning Ltd | Wholesale & retail | 2025 |
| MACHY2005 Construct Ltd | Construction | 2022 |
| Maciej Szkodowski Ltd | Information & communication | 2025 |
| MACIEK4X Ltd | Financial services | 2025 |
| Mackcon Pipeline Services Ltd | Construction | 2015 |
| Mackeye Limited | Health & social care | 2023 |
| Maclean Builders Limited | Extraterritorial | 2007 |
| Macoc Educational Services Ltd | Education | 2024 |
| Macomms Ltd | Construction | 2023 |
| Maconleo Ltd | Information & communication | 2014 |
| Macrete Home Solutions Limited | Real estate | 2019 |
| Macrocyber Enterprises Limited | Information & communication | 2006 |
| Macrodata Analysis Ltd | Professional & scientific | 2025 |
| MAD Croc Limited | Hospitality | 2015 |
| MAD4BIKES Ltd | Wholesale & retail | 2015 |
| Madadin Transport Ltd | Transport & logistics | 2024 |
| Madalin 4 Construction Limited | Construction | 2021 |
| Madaripur Trading Ltd | Wholesale & retail | 2018 |
| Madden Mechanical Limited | Construction | 2015 |
| Maddison Carter Ltd | Wholesale & retail | 2026 |
| Made by Meesh Ltd | Arts & recreation | 2020 |
| Made IT Marketing Ltd | Professional & scientific | 2021 |
| Made of Money Ltd | Wholesale & retail | 2017 |
| MADE2CARE Ltd | Hospitality | 2026 |
| MADE4ORDER Ltd | Manufacturing | 2025 |
| Madeena Limited | Information & communication | 2026 |
| Madhuram Products Limited | Wholesale & retail | 2025 |
| Madi Investments Limited | Real estate | 2026 |
| Madina Catering and Wholesale Limited | Wholesale & retail | 2024 |
| Madina Market Ltd | Wholesale & retail | 2026 |
| Madinah Munawara Investment Limited | Real estate | 2024 |
| Madlova Limited | Wholesale & retail | 2026 |
| Madrian Care Ltd | Administrative & support | 2023 |
| MAE Global Limited | Wholesale & retail | 2025 |