| MTT Consulting Ltd | Construction | 2018 |
| Mtyn Limited | Administrative & support | 2013 |
| Muge EPM Solutions Limited | Professional & scientific | 2018 |
| Mughal Asset Management Limited | Real estate | 2019 |
| Mukherjee-Darrad Medical Ltd | Health & social care | 2021 |
| Mukon Digital Ltd | Professional & scientific | 2024 |
| Mulberry & Peak Properties Limited | Real estate | 2023 |
| Mulberry Advisors Limited | Administrative & support | 2023 |
| Mulberry Court (Shirley) Limited | Real estate | 2008 |
| Mulberry House (Dorking) Limited | Households | 2021 |
| Mulberry Place Residents Management Limited | Households | 2024 |
| Multi Home Management Ltd | Hospitality | 2025 |
| Multi-Skilled ENG Ltd | Professional & scientific | 2026 |
| Multifit (UK) Ltd | Construction | 2007 |
| Multifleet Group Limited | Financial services | 2024 |
| Multifleet Vehicle Management Limited | Wholesale & retail | 2000 |
| Multish Ltd | Information & communication | 2020 |
| MUM & DAD Properties Ltd | Real estate | 2019 |
| Mumbles Ltd | Wholesale & retail | 2017 |
| Mummyfit (Solihull & Warwickshire) Ltd | Arts & recreation | 2025 |
| Muni Private Finance Ltd | Real estate | 2016 |
| Muno Limited | Health & social care | 2011 |
| Muon 3D Technologies Ltd | Manufacturing | 2024 |
| Murfo Limited | Real estate | 2017 |
| Murfo Tech Limited | Information & communication | 2025 |
| Murrall's Kitchen Ltd | Hospitality | 2021 |
| Murray Jones Engineering (Sussex) Limited | Professional & scientific | 2011 |
| Murray Utilities Ltd | Construction | 2018 |
| Murrell Green Land Ltd | Construction | 2025 |
| Murtagh Group Consulting Limited | Other services | 2018 |
| Musa Engineering Limited | Construction | 2019 |
| Muscle Wellness Ltd | Other services | 2024 |
| Musculoskeletal Health Ltd | Health & social care | 2019 |
| Mush Transport Ltd | Transport & logistics | 2004 |
| Music Box Nursery Ltd | Extraterritorial | 2013 |
| Music Matters Limited | Wholesale & retail | 1990 |
| Music, Food & FUN Ltd | Arts & recreation | 2023 |
| Muskie Ltd | Wholesale & retail | 2022 |
| Must Chai Ltd | Wholesale & retail | 2025 |
| Mustang Hospitality Ltd | Hospitality | 2023 |
| Mustard Financial Ltd | Financial services | 2015 |
| Mustin Pearce Financial Management Ltd | Professional & scientific | 2022 |
| Mutoon.Co.Uk Limited | Information & communication | 2025 |
| Mutual Property Investments Limited | Professional & scientific | 2003 |
| MV Forward Limited | Real estate | 2016 |
| MVB Restoration Ltd | Construction | 2013 |
| Mvichi Ltd | Extraterritorial | 2024 |
| Mvsj Limited | Other services | 2024 |
| MW Business Consulting Ltd | Professional & scientific | 2012 |
| MW Praxis Ltd | Professional & scientific | 2025 |
| MWM Distributors Limited | Other services | 2000 |
| MWS Financial Advisers Limited | Administrative & support | 2001 |
| MWS Systems Ltd | Administrative & support | 2017 |
| Mxchine Ltd | Manufacturing | 2014 |
| Mxvp Limited | Real estate | 2025 |
| My Apple Core Ltd | Arts & recreation | 2023 |
| My Crispy Crust Ltd | Hospitality | 2023 |
| My Exceptional Personnel Limited | Health & social care | 2014 |
| My Fate Interiors Limited | Wholesale & retail | 2013 |
| My Financial Controller Limited | Professional & scientific | 2005 |
| My Leaf Commercial Ltd | Wholesale & retail | 2022 |
| My Mental Mojo Ltd | Health & social care | 2026 |
| My Property Launch Ltd | Real estate | 2021 |
| My Software GUY Ltd | Information & communication | 2014 |
| My Tidy Office Ltd | Professional & scientific | 2023 |
| My Training Limited | Education | 2024 |
| My Travel Assistant Ltd | Administrative & support | 2022 |
| My Travel PA Limited | Administrative & support | 2019 |
| My Virtual Finance Director Limited | Professional & scientific | 2021 |
| My Way Services Ltd | Health & social care | 2023 |
| Mybuild Ltd | Construction | 2019 |
| Mycad Integrated Services Limited | Professional & scientific | 2013 |
| Mydoc Ltd | Health & social care | 2015 |
| Mydrives (Midlands) Ltd | Construction | 2018 |
| Mykonos @ Distrykt & Co Ltd | Construction | 2021 |
| Mylan Oscar Property Letting Limited | Real estate | 2025 |
| Mylandscapes (Midlands) Ltd | Administrative & support | 2020 |
| Myles Ahead Roofing Ltd | Construction | 2025 |
| Mynd Wellness Ltd | Wholesale & retail | 2026 |
| Myproductshop Ltd | Manufacturing | 2025 |
| MYRAA4 Ltd | Wholesale & retail | 2023 |
| Myriad Private Limited | Real estate | 2024 |
| Mystique Properties Ltd | Real estate | 2019 |
| MZ Architecture Limited | Professional & scientific | 2022 |
| N a Investments Limited | Real estate | 2018 |
| N C Earthworks Ltd | Professional & scientific | 2014 |
| N Hayes Developments Ltd | Real estate | 2025 |
| N J M Electrical Limited | Construction | 2007 |
| N&A Real Estate 1 Ltd | Real estate | 2025 |
| N&N Akbar Ltd | Real estate | 2022 |
| N&W Wellness Ltd | Health & social care | 2026 |
| N-Cap Flooring Limited | Construction | 2011 |
| N-Xco Limited | Real estate | 2013 |
| N. a. Enterprise Limited | Health & social care | 2008 |
| N. N. Caterers Limited | Hospitality | 2005 |
| N.A. Eyecare Limited | Health & social care | 2010 |
| N.A.C Electrical Ltd | Construction | 2020 |
| N.E.C. Mechanical Services Limited | Energy | 1999 |
| N.J.R. Building Services Limited | Professional & scientific | 2005 |
| N.L.V Home Improvements Ltd | Construction | 2025 |