| Mahil Portfolio Limited | Real estate | 2013 |
| Mahjoods Property Limited | Real estate | 2024 |
| Mahjouri Nexus Limited | Administrative & support | 2025 |
| Mahmood & Azam Investments Limited | Real estate | 2023 |
| Mahmood & Sons Limited | Financial services | 2018 |
| Mahmood Commercial Limited | Real estate | 2026 |
| Mahmood Property Services Limited | Real estate | 2020 |
| Mahmoods Estates Ltd | Real estate | 2026 |
| Mahran Anwer Mohammed Horamee Ltd | Real estate | 2025 |
| MAI Medical Limited | Health & social care | 2016 |
| MAI Nails Ltd | Other services | 2024 |
| MAI Thai Massage Ltd | Other services | 2021 |
| Maid Marian Convenience Limited | Wholesale & retail | 2014 |
| Maid Marian Property Management Ltd | Real estate | 2016 |
| Maid Marinade Ltd | Wholesale & retail | 2020 |
| Maidenhead V.E. Limited | Other services | 1997 |
| Maidstone Drive Records Ltd | Wholesale & retail | 2025 |
| Mail-Hub UK Limited | Transport & logistics | 2020 |
| Mailing, Export and Distribution Services Limited | Administrative & support | 1982 |
| Maillard Malaga Limited | Transport & logistics | 2025 |
| Mailmanager Limited | Information & communication | 2016 |
| Mailorder Beads Limited | Wholesale & retail | 2017 |
| Maini Group Investment Limited | Households | 2021 |
| Maini Partnerships Ltd | Real estate | 2019 |
| Maini Properties Limited | Real estate | 2016 |
| Mainline Property Services Ltd | Households | 2024 |
| Mainline Site Services Limited | Construction | 2014 |
| Mains Services Ltd | Construction | 2019 |
| Mainstone Developments Ltd | Construction | 2019 |
| Mainstream-Enterprise Ltd | Wholesale & retail | 2025 |
| Maintech Engineering Ltd | Professional & scientific | 2024 |
| Maintenance & Technical Management Limited | Construction | 2020 |
| Maintenance Free Fencing Ltd | Construction | 2025 |
| Maintenance Services (Midlands) Limited | Administrative & support | 2014 |
| Maintenance Team East Midlands Ltd | Administrative & support | 2019 |
| Mainwise Limited | Other services | 1988 |
| Maison & Key Holdings Ltd | Financial services | 2025 |
| Maison Dana Ltd | Wholesale & retail | 2026 |
| Maison DE L'Elegance Ltd | Wholesale & retail | 2025 |
| Maison Diamond Ltd | Other services | 2025 |
| Maison DU Fleurs Ltd | Hospitality | 2020 |
| Maison Haven Furniture Limited | Wholesale & retail | 2025 |
| Maison Management UK Limited | Real estate | 2024 |
| Maison Stays Limited | Real estate | 2023 |
| Maite N Sami Ltd | Hospitality | 2021 |
| MAITEE3 Ltd | Health & social care | 2013 |
| Maitland Education Limited | Education | 2025 |
| MAJ Plumbing and Electrical Ltd | Construction | 2021 |
| MAJ Residential Ltd | Real estate | 2026 |
| MAJ37 Ltd | Health & social care | 2026 |
| Majestic Bingo Limited | Arts & recreation | 2013 |
| Majestic Commercial & Domestic Cleaning Ltd | Administrative & support | 2025 |
| Majestic Grill (Nottingham) Ltd | Hospitality | 2024 |
| Majestic Mobile Ltd | Wholesale & retail | 2024 |
| Majestic Trophies Limited | Professional & scientific | 1976 |
| Majic Footwear Ltd | Wholesale & retail | 2023 |
| Majid Corporation Ltd | Real estate | 2022 |
| Majid Property Developments Limited | Real estate | 2015 |
| Majid Property Ltd | Real estate | 2024 |
| Majlis Ltd | Construction | 2026 |
| Major Labia Limited | Arts & recreation | 2022 |
| Major Oak Coaching Limited | Arts & recreation | 2012 |
| Major Oak Education Ltd | Administrative & support | 2017 |
| Major Oak Groundwork Limited | Construction | 2023 |
| Major Oak Holdings Limited | Financial services | 2022 |
| Major Oak Innovation Limited | Manufacturing | 2018 |
| Major Oak Property Ltd | Real estate | 2025 |
| Majour Corporation Limited | Financial services | 2021 |
| Majumder Properties Limited | Real estate | 2023 |
| MAK Architecture Ltd | Professional & scientific | 2025 |
| MAK Foods Limited | Hospitality | 2024 |
| MAK More Ltd | Wholesale & retail | 2009 |
| MAK Nottingham Ltd | Hospitality | 2023 |
| Makaav Ltd | Wholesale & retail | 2025 |
| Makamana Limited | Hospitality | 2018 |
| Makdici Estates Limited | Real estate | 2025 |
| Make Each Clean Count Ltd | Administrative & support | 2019 |
| Make HAY Ethical E-Media Ltd | Information & communication | 2004 |
| Make IT Games Ltd | Manufacturing | 2021 |
| Make IT Media Limited | Information & communication | 2012 |
| Make Some Noise Media Ltd | Professional & scientific | 2015 |
| Make to Make CIC | Arts & recreation | 2014 |
| Make to Measure Ltd | Manufacturing | 2026 |
| Make UP Nation Ltd | Other services | 2025 |
| Makeahouseahome Ltd | Real estate | 2021 |
| Makeen Homes Ltd | Real estate | 2024 |
| Makers of Imaginary Worlds Ltd | Arts & recreation | 2019 |
| Makies Ltd | Hospitality | 2024 |
| Making Broken Beautiful Limited | Arts & recreation | 2024 |
| Makj Limited | Real estate | 2020 |
| Makka Group Ltd | Hospitality | 2025 |
| Makkah (Nottingham) Ltd | Wholesale & retail | 2021 |
| Makks Services Limited | Administrative & support | 2018 |
| Makomah Ltd | Health & social care | 2015 |
| Maksoud Medical Limited | Health & social care | 2004 |
| Makulu Enterprises Limited | Wholesale & retail | 2016 |
| Makwana Partners Ltd | Health & social care | 2025 |
| Mala Global Limited | Wholesale & retail | 2024 |
| Malaak Ltd | Other services | 2025 |
| Malaj Property Limited | Real estate | 2023 |