| Marque Restore Chrome Plating Limited | Manufacturing | 2000 |
| Marslim Ltd | Transport & logistics | 2026 |
| Martin J. Butler Limited | Manufacturing | 1995 |
| Martin Niblett Limited | Construction | 2014 |
| Martin Robey Engineering Limited | Agriculture & fishing | 1982 |
| Martin Robey Holdings Limited | Professional & scientific | 1986 |
| Martin Robey Properties Limited | Real estate | 2016 |
| Martin Robey Sales Limited | Wholesale & retail | 1986 |
| Martin’S Roofing Contractors Ltd | Construction | 2021 |
| Martyn Taylor Limited | Construction | 2004 |
| Marxfix Limited | Construction | 2022 |
| Mary ANN Evans Hospice | Health & social care | 1992 |
| Mary ANN Evans Promotions Limited | Arts & recreation | 1996 |
| Mary Carroll Close Management Company(Ansley) Ltd | Real estate | 2020 |
| Maryvale Rise Limited | Real estate | 2023 |
| Masonic Buildings (Nuneaton) Limited | Other services | 1929 |
| Masons Carpentry Ltd | Construction | 2009 |
| Masons Interiors (Midlands) Ltd | Construction | 2014 |
| Master Build Construction Ltd | Construction | 2022 |
| Masters of INK Academy Ltd | Education | 2026 |
| Masters of INK Limited | Education | 2022 |
| Masters Production Services Limited | Arts & recreation | 2011 |
| MAT Foods Limited | Hospitality | 2022 |
| Match Fit KIT Schoolwear Limited | Wholesale & retail | 2008 |
| Matei Trans Limited | Transport & logistics | 2016 |
| Material Advantage Holdings Limited | Financial services | 2022 |
| Mathias Limited | Transport & logistics | 2022 |
| Matmoses Limited | Administrative & support | 2021 |
| Matty Trans Ltd | Transport & logistics | 2023 |
| Matyjas Property Ltd | Real estate | 2020 |
| Mavudy Holdings Limited | Financial services | 2024 |
| Mavudy Lettings Ltd | Real estate | 2025 |
| MAW Property Services Limited | Real estate | 2004 |
| MAX Co. Transport Limited | Transport & logistics | 2016 |
| Maximusmanagementofficial Limited | Extraterritorial | 2024 |
| Mayaaa Ltd | Hospitality | 2023 |
| Mayes Consulting Ltd | Manufacturing | 2000 |
| Mayfly Properties Limited | Construction | 2016 |
| Maystone Digital Ltd | Information & communication | 2026 |
| Mazilu Couriers Limited | Transport & logistics | 2022 |
| MB Building (Midlands) Limited | Construction | 2017 |
| MB Global Ltd | Hospitality | 2012 |
| MB Renovation Services Limited | Construction | 2023 |
| MBA Joinery Ltd | Construction | 2022 |
| Mbemba Distribution Ltd | Wholesale & retail | 2018 |
| MBI Partners Limited | Construction | 2020 |
| Mbong Ltd | Real estate | 2024 |
| MBW Assosciates Limited | Administrative & support | 2023 |
| Mcallister Electrical Ltd | Construction | 2025 |
| MCC Civils Ltd | Construction | 2023 |
| Mcc's Missions Ltd | Arts & recreation | 2018 |
| Mccjproperty Ltd | Households | 2023 |
| MCD Property Maintenance Ltd | Administrative & support | 2025 |
| Mcfadden Civil Engineering Limited | Construction | 2024 |
| Mcfadden Holdings Limited | Financial services | 2025 |
| MCG Media Ltd | Information & communication | 2012 |
| MCG Programing Ltd | Manufacturing | 2025 |
| Mckay Creative Enterprises Ltd | Financial services | 2025 |
| Mclaughlin Curnuck Investments Limited | Financial services | 2026 |
| Mclellan Partnership Ltd | Professional & scientific | 2023 |
| Mcmurchy Holdings Limited | Financial services | 2017 |
| MCS (Parts) Limited | Wholesale & retail | 1995 |
| MDL Exhibition & Building Services Ltd | Manufacturing | 2023 |
| MDM Transport Ltd | Transport & logistics | 2023 |
| MDO Sports Group Limited | Education | 2025 |
| MDS Flooring Ltd | Construction | 2012 |
| Mdsdeliverysolutions Limited | Transport & logistics | 2025 |
| Meadow Rise Care Ltd | Health & social care | 2025 |
| Meadow Rock Limited | Households | 2026 |
| Meadow Tree Care Ltd | Administrative & support | 2025 |
| Meadows Wholesales Ltd | Wholesale & retail | 2026 |
| Meadowview Chickens Limited | Agriculture & fishing | 2020 |
| Meah Education Ltd | Education | 2026 |
| Meah Labs Ltd | Information & communication | 2025 |
| MEB Construction Consulting Ltd | Professional & scientific | 2017 |
| MEB Contracting Ltd | Wholesale & retail | 2024 |
| Mecas Trans Ltd | Transport & logistics | 2022 |
| Med-House Ltd | Health & social care | 2022 |
| Med-International UK Health Agency Ltd | Health & social care | 2023 |
| Medica Aesthetics Ltd | Health & social care | 2010 |
| Medical Clearance Ltd | Financial services | 2023 |
| Medusa Ventures Ltd | Professional & scientific | 2020 |
| Megomerhaba Ltd | Wholesale & retail | 2026 |
| Meikleham Hospitality Ltd | Hospitality | 2026 |
| Melissa Coffee Ltd | Hospitality | 2018 |
| Melka Health Ltd | Health & social care | 2023 |
| Mellee Limited | Construction | 2021 |
| Mellor & Lovelady Holdings Ltd | Administrative & support | 2024 |
| Melnex Ltd | Other services | 2012 |
| Melon Homes Ltd | Real estate | 2018 |
| Mendwell Ltd | Construction | 2025 |
| Mentoring Arts and Diverse Educators CIC | Education | 2023 |
| Mercia Export Enterprises Limited | Wholesale & retail | 1990 |
| Mercia Flooring Group Limited | Construction | 2022 |
| Mercia Housing Solutions Ltd | Real estate | 2025 |
| Mercia Investments (East) Limited | Real estate | 1968 |
| Mercurial Enterprises Ltd | Professional & scientific | 2018 |
| Mere Real Estate Limited | Real estate | 2025 |
| Merevale Transport Ltd | Transport & logistics | 2022 |
| Mergrate Limited | Arts & recreation | 2023 |