| MAD Hatters Day Nursery Limited | Education | 2014 |
| Madamombe Logistics Ltd | Transport & logistics | 2024 |
| Maddalena Creative Services Limited | Professional & scientific | 2003 |
| Maddison Homes Limited | Construction | 2007 |
| Made (Digbeth 4) Limited | Construction | 2023 |
| Made Architecture Limited | Professional & scientific | 2010 |
| Made Design and Build Limited | Construction | 2023 |
| Made Design and Build Two Limited | Construction | 2025 |
| Made Property Group Ltd | Construction | 2022 |
| Made Real Estate Ltd | Construction | 2023 |
| Made Social Care Limited | Health & social care | 2011 |
| Madft Limited | Real estate | 2021 |
| Madslug Ltd | Information & communication | 2014 |
| Magden Limited | Extraterritorial | 1999 |
| Magenta Enterprises Limited | Financial services | 2023 |
| Magic Accountancy Services Ltd | Professional & scientific | 2013 |
| Magic Business Essentials Ltd | Professional & scientific | 2008 |
| Magic Carpets (Wholesale) Limited | Wholesale & retail | 1994 |
| Magma Investment Enterprises Limited | Professional & scientific | 2021 |
| Magma Software Limited | Information & communication | 2014 |
| Magna Civils Limited | Construction | 2021 |
| Magna Consultants Limited | Professional & scientific | 2014 |
| Magnet Property Investments Limited | Real estate | 2016 |
| Magnolia House N1 Ltd | Real estate | 2025 |
| Magnos Somnia Consultancy Limited | Other services | 2019 |
| Magnus Digital Limited | Information & communication | 2026 |
| Maguire & Co (751 Warwick Road) Limited | Construction | 2025 |
| Magus Acumen Ltd | Professional & scientific | 2019 |
| Mahadevnandi Limited | Construction | 2024 |
| Mahal Sweet Shop Ltd | Hospitality | 2024 |
| Maharg Investments Limited | Real estate | 2004 |
| Mahesh Consultants Limited | Real estate | 2018 |
| MAHIMA2014LTD Limited | Health & social care | 2015 |
| Mahindra Cars Distributors (UK) Limited | Wholesale & retail | 2012 |
| Mahnoorbridal Ltd | Other services | 2022 |
| Maia Engineering Services Limited | Professional & scientific | 2002 |
| Mail Order Sales Ltd | Wholesale & retail | 2002 |
| Main Event Products Limited | Manufacturing | 2000 |
| Main Street (Silsoe) Limited | Construction | 2018 |
| Mainbrace Limited | Real estate | 2004 |
| Maini Wholesale Distribution Limited | Real estate | 2010 |
| Mainly Ford Ltd | Wholesale & retail | 2025 |
| Mainpipe Ltd | Construction | 2026 |
| Maintain (WM) Ltd | Other services | 2018 |
| Maintain Building Services Ltd | Construction | 2022 |
| Maintain Roofing Ltd | Construction | 2022 |
| Maison AL Fattah Aesthetics Ltd | Health & social care | 2026 |
| Maison Capital Limited | Real estate | 2026 |
| Maison XI Ltd | Other services | 2025 |
| Maisonmars Limited | Real estate | 2018 |
| Maiva Properties Ltd | Real estate | 2022 |
| Majdanski Property Ltd | Real estate | 2018 |
| Majorworks Limited | Real estate | 1998 |
| Make UP Spot Limited | Other services | 2018 |
| Make-Up by Mollie Ltd | Wholesale & retail | 2020 |
| Makeitsimple Consulting Limited | Information & communication | 2018 |
| Makers Yard Ltd | Households | 2026 |
| Making IT Happen Ltd | Education | 2025 |
| Malcolm Brooks Limited | Wholesale & retail | 1960 |
| Maliha's Foods Limited | Hospitality | 2023 |
| Malik Property Investment Limited | Real estate | 2018 |
| Malik-Swift Services Ltd | Transport & logistics | 2023 |
| Malku Community Hub CIC | Education | 2026 |
| Malku Training and Education Ltd | Education | 2023 |
| Mallatite Limited | Manufacturing | 1991 |
| Mallatite Minor Structures & Products Ltd | Manufacturing | 2021 |
| Maloney Asset Management Ltd | Real estate | 2025 |
| Malthouse Court (Warwick) Management Company Limited | Households | 2004 |
| Malvern Consulting Limited | Professional & scientific | 2010 |
| Malvern House Acquisitions Limited | Administrative & support | 2019 |
| Malvern House Real Estate Investors Limited | Financial services | 2015 |
| Malvern North Ltd | Real estate | 2024 |
| Malvern Park Estates Limited | Real estate | 2013 |
| Mama Turtle Ltd | Information & communication | 2012 |
| Mambos Stilled Pizza Limited | Hospitality | 2024 |
| MAN Commercial Protection Limited | Administrative & support | 2003 |
| Manage My Utilities Limited | Professional & scientific | 2019 |
| Manage UR Property Limited | Real estate | 2016 |
| Managed Care Solutions Limited | Administrative & support | 2015 |
| Mancosus Limited | Financial services | 2022 |
| Manderley Residents Management Company Limited | Households | 2010 |
| Mangat Medical Services Limited | Health & social care | 2016 |
| Mango Delivery Ltd | Hospitality | 2014 |
| Mango Tree Dental Limited | Health & social care | 2021 |
| Mangopoint UK Limited | Administrative & support | 2024 |
| Manmore Limited | Construction | 2018 |
| Mann Cave Limited | Hospitality | 2017 |
| Mann Lettings Limited | Real estate | 2026 |
| Mann's Medical Services Limited | Health & social care | 2002 |
| Mannix Security Consultants Limited | Administrative & support | 2015 |
| Manor Court (Leamington) Limited | Households | 2003 |
| Manor Court (Solihull) RTM Company Limited | Households | 2023 |
| Manor Farm (Broad Hinton) Limited | Construction | 2024 |
| Manor Hargman Limited | Administrative & support | 1973 |
| Manor Homes Limited | Construction | 1979 |
| Manor House Records Ltd | Manufacturing | 2026 |
| Manor Lane (Manor Farm) Ltd | Construction | 2024 |
| Manor Park Farm Management Company Limited | Households | 1995 |
| Manor Road Residents (Dorridge) Management Company Limited | Extraterritorial | 2014 |
| Manor Stables Management Company Limited | Real estate | 1997 |