| Macon Management and Design Limited | Professional & scientific | 1991 |
| Madaleine Bassett Ltd | Arts & recreation | 2023 |
| Madalin Grigorie Ltd | Transport & logistics | 2018 |
| Madama Cleaning Service Limited | Administrative & support | 2026 |
| Maddison Legal Services Limited | Administrative & support | 2004 |
| Madeley Aggregates Limited | Extraterritorial | 2006 |
| Madeley Developments Limited | Construction | 2003 |
| Madeley HEY Limited | Real estate | 1972 |
| Madeley Rural Community Charity | Education | 2009 |
| Maestro Consultants Ltd | Professional & scientific | 2023 |
| Magdalen 1953 Limited | Extraterritorial | 2013 |
| Magenta Moon Limited | Administrative & support | 2014 |
| Magformers UK Limited | Wholesale & retail | 2015 |
| Magnartism Limited | Wholesale & retail | 2008 |
| Magnet Homes Limited | Real estate | 2020 |
| Magnetic I D Limited | Information & communication | 2007 |
| Magnetix Therapy Limited | Wholesale & retail | 2013 |
| Magpie Cards Limited | Wholesale & retail | 2014 |
| Magvision Limited | Professional & scientific | 2021 |
| MAID2CLEAN (NW) Ltd | Administrative & support | 2012 |
| Mailboxx Limited | Wholesale & retail | 2023 |
| Main & Gerrard Ltd | Information & communication | 2014 |
| Maison Construction and Landscapes Limited | Construction | 2020 |
| Makarsky Ltd | Transport & logistics | 2019 |
| Make Moving Easy Ltd | Extraterritorial | 2021 |
| Making Momentum CIC | Health & social care | 2021 |
| Malabar Property Company Limited | Real estate | 2014 |
| Malindi Consultancy Limited | Professional & scientific | 2006 |
| MALONE18 Ltd | Transport & logistics | 2023 |
| Maloneys Roof Build Ltd | Construction | 2024 |
| Maltbykeegan Limited | Extraterritorial | 2016 |
| Mama Afrikana Ltd | Wholesale & retail | 2025 |
| Mama MIA Eats Ltd | Hospitality | 2026 |
| Man.M.Wind Ltd | Construction | 2023 |
| Manage Hospitality Platform Ltd | Information & communication | 2024 |
| Manchester Analytics Ltd | Professional & scientific | 2025 |
| Mandi Transport Ltd Ltd | Transport & logistics | 2019 |
| Manifesting Memories Limited | Real estate | 2022 |
| Manning Access Ltd | Manufacturing | 2024 |
| Manor Farm Englesea Brook Cattery Limited | Other services | 2024 |
| Manor Haus Ltd | Real estate | 2026 |
| Manor Orchard Management Company Limited | Households | 2017 |
| Mansell Group Ltd | Other services | 2025 |
| Mantar Assist Ltd | Administrative & support | 2013 |
| Manufactured Components Company Limited | Professional & scientific | 2016 |
| MAP Scrap Metals Limited | Water & waste | 2014 |
| Maple Leaf Designs Limited | Construction | 2001 |
| Marangoni Junior Limited | Information & communication | 2025 |
| Marathon Homes Ltd | Real estate | 2025 |
| Maravilla Pictures Limited | Information & communication | 2009 |
| Marcel Driving Services Ltd | Transport & logistics | 2019 |
| Marcin Garage Ltd | Wholesale & retail | 2025 |
| Marina Padel Limited | Arts & recreation | 2026 |
| Mario Driver Ltd. | Transport & logistics | 2015 |
| MARIO23 Travel Ltd | Transport & logistics | 2026 |
| MARIOTRANS2015 Ltd | Transport & logistics | 2019 |
| Mariusz Z Transportation Ltd. | Transport & logistics | 2019 |
| Mark Clubbe Limited | Construction | 2016 |
| Mark Hancock Caravans Limited | Other services | 2003 |
| Mark J Wilson Plumbing and Renewables Ltd | Construction | 2022 |
| Mark Titley Limited | Agriculture & fishing | 2019 |
| Markden (Audlem Projects) Limited | Construction | 2017 |
| Marks Top Properties Limited | Administrative & support | 2026 |
| Marlena &M Ltd | Construction | 2025 |
| Marlow Richards Ltd | Real estate | 2018 |
| Marrington Construction Limited | Construction | 2005 |
| Marsden International Limited | Transport & logistics | 1991 |
| Marshall Property Partnership Ltd | Real estate | 2020 |
| Marshall Three Investments Ltd | Financial services | 2025 |
| Marshmallow Kids Ltd | Other services | 2021 |
| Marshmallow Spa & Parties Ltd | Other services | 2022 |
| Marslav Transport Ltd | Transport & logistics | 2022 |
| Mart Services Ltd | Wholesale & retail | 2023 |
| Marteck Ltd | Professional & scientific | 2026 |
| Martian Red Limited | Information & communication | 2010 |
| Martin Homes Improvement Ltd | Administrative & support | 2021 |
| Martin Massey Limited | Construction | 2013 |
| Martin Turner Performance Psychology Services Ltd | Health & social care | 2019 |
| Martins Amenities Limited | Real estate | 1997 |
| Martins Dried Flowers Limited | Wholesale & retail | 2011 |
| Mary Matha South Indian Store Limited | Wholesale & retail | 2023 |
| MAS Parts Limited | Wholesale & retail | 2020 |
| Mashuk Ltd | Real estate | 2020 |
| Mason Property Experts Ltd | Real estate | 2023 |
| Mass Spectrometry Solutions Ltd | Manufacturing | 2005 |
| Massey Bros LLP | | 2011 |
| Massey Bros Partnership LP | | 2011 |
| Massey Harper Limited | Manufacturing | 2012 |
| Massey Software Solutions Limited | Information & communication | 1999 |
| Maston Transport Ltd | Transport & logistics | 2018 |
| Materialise Group Ltd | Financial services | 2023 |
| Matfell Motors Ltd | Wholesale & retail | 2026 |
| Matsmi Services Ltd | Construction | 2017 |
| Matt Griffiths Holdings Ltd | Real estate | 2023 |
| Matt Hillier TV, Film & Photography Limited | Information & communication | 2015 |
| Matthew Baldwin Holdings Limited | Financial services | 2022 |
| Matthew Baldwin Property Limited | Real estate | 2022 |
| Matthew Burkill Lettings Ltd | Real estate | 2022 |
| Matthews Rail Ltd | Construction | 2014 |
| Matthews UK Management Limited | Professional & scientific | 2014 |