| Markden Homes SPV 5 Limited | Construction | 2023 |
| Markden Homes SPV 6 Limited | Construction | 2023 |
| Markden Homes SPV 7 Limited | Construction | 2024 |
| Markden Homes SPV3 Limited | Construction | 2022 |
| Markdon Ltd | Professional & scientific | 2003 |
| Markem-Imaje Limited | Manufacturing | 2013 |
| Market Ashington Estates Limited | Other services | 2025 |
| Market Intelligence Partners Limited | Professional & scientific | 2024 |
| Market Launch Ltd | Information & communication | 2026 |
| Market Place Garage Limited | Wholesale & retail | 2019 |
| Market Regent Limited | Professional & scientific | 2025 |
| Markfield Services Ltd | Manufacturing | 2013 |
| Marlo Hats Ltd | Wholesale & retail | 2025 |
| Marm Global Services Ltd | Transport & logistics | 2026 |
| Marmalade (GBR) Ltd | Professional & scientific | 2019 |
| Marmic Construction Ltd | Construction | 2021 |
| Marriagehouse Ltd | Professional & scientific | 2023 |
| Marriott Legal Services Limited | Professional & scientific | 2022 |
| Marronford Limited | Real estate | 1974 |
| Marsh Care Ltd | Public administration | 2020 |
| Mart & ENI Ltd | Construction | 2020 |
| Martin a Lewis Ltd | Education | 2012 |
| Martin Brooks Project Management Ltd | Construction | 2025 |
| Maru Group Limited | Professional & scientific | 2015 |
| Maru/Usurv Limited | Professional & scientific | 2011 |
| Marvel Kitchen Limited | Hospitality | 2022 |
| Marvelous Trading Limited | Wholesale & retail | 2021 |
| Marwa Holdings Limited | Real estate | 2018 |
| Marx & Engels International Humanities Exchange Association | Professional & scientific | 2024 |
| Maryam Export Trading Limited | Wholesale & retail | 2025 |
| Masaya Stays Ltd | Hospitality | 2025 |
| Mash UP Ltd | Wholesale & retail | 2025 |
| Masio Limited | Wholesale & retail | 2010 |
| Maslen Holdings Limited | Health & social care | 2025 |
| Maslow Associates Limited | Administrative & support | 2019 |
| Maslow Consult Limited | Information & communication | 2024 |
| Mason Williams (Manchester) Limited | Professional & scientific | 1986 |
| Masons Entertainments Limited | Hospitality | 2017 |
| Mass-Gao Consulting Ltd | Health & social care | 2020 |
| Massati Ltd | Wholesale & retail | 2026 |
| Master Construction Group Ltd | Construction | 2026 |
| Master Guider Ltd | Construction | 2025 |
| Master Motion Pictures Ltd | Information & communication | 2024 |
| Master of Plaster Ltd | Construction | 2026 |
| Master Plan Trustees Ltd | Administrative & support | 2016 |
| MAT Finishers Ltd | Construction | 2022 |
| Matamim Ltd | Hospitality | 2018 |
| Mataz Optical Limited | Health & social care | 2023 |
| Matbro Properties Ltd | Real estate | 2025 |
| Mateela Enterprises Ltd | Wholesale & retail | 2026 |
| Maten Trans Ltd | Transport & logistics | 2025 |
| Matesplanet Limited | Information & communication | 2021 |
| Mathman Estates Ltd | Real estate | 2024 |
| Matillion Limited | Information & communication | 2010 |
| Matkor Ltd | Health & social care | 2023 |
| Matlib Consultancy Ltd | Professional & scientific | 2024 |
| Matlib Limited | Financial services | 2024 |
| Matrafisc Dance Company Ltd | Arts & recreation | 2023 |
| Matt Hill Audio Ltd | Information & communication | 2014 |
| Mattalex Ltd | Construction | 2026 |
| Mattbay Limited | Other services | 2017 |
| Matuna Ltd | Wholesale & retail | 2021 |
| MAV Construction Ltd | Construction | 2020 |
| Maventech E Solutions Limited | Wholesale & retail | 2025 |
| Maveon Logistic Ltd | Transport & logistics | 2020 |
| Mavin Properties Limited | Real estate | 2019 |
| Mavo Group Ltd | Construction | 2026 |
| Mawdesley Leisure Ltd | Arts & recreation | 2014 |
| Mawdsley-Brooks & Company Limited | Wholesale & retail | 1895 |
| Mawdsleys Group Investments Limited | Professional & scientific | 2009 |
| Mawdsleys Trustee Limited | Professional & scientific | 1941 |
| MAX Deal Wholesale Limited | Wholesale & retail | 2026 |
| Maxie Express Ltd | Transport & logistics | 2019 |
| Maximus Roman Estates Limited | Real estate | 2020 |
| Maxone International Ltd | Transport & logistics | 2017 |
| MAY 123 Limited | Real estate | 2013 |
| Maybank Conservation Ltd | Professional & scientific | 2025 |
| Maybush Healthcare Limited | Health & social care | 2021 |
| Maybush Healthcare Solutions Ltd | Real estate | 2022 |
| Maycorner Ltd | Manufacturing | 2025 |
| Mayer Holdings Ltd | Administrative & support | 2025 |
| Mayer Investments Limited | Real estate | 1957 |
| Mayfair Estates (M/C) Ltd | Construction | 2005 |
| Mayfair Services Ltd | Professional & scientific | 2024 |
| Maylinx Ltd | Professional & scientific | 2013 |
| Maylor Ltd | Information & communication | 2025 |
| Mayo Stone Supplies Ltd | Water & waste | 2020 |
| Mayquinn Limited | Information & communication | 2014 |
| Mazaltov Ltd | Real estate | 2024 |
| Maze Guide Psychology Limited | Education | 2020 |
| Mazel Investments MCR Ltd | Real estate | 2022 |
| Mazylis 1989 Limited | Wholesale & retail | 2018 |
| MB & H Estates Ltd | Real estate | 2019 |
| MB Auto Body Work & Spare Parts Ltd | Wholesale & retail | 2025 |
| MB Consulting Solutions Ltd | Professional & scientific | 2016 |
| MB Real Estate Investments Ltd | Real estate | 2025 |
| MB Resells Ltd | Wholesale & retail | 2026 |
| MB Twostars Events Ltd | Wholesale & retail | 2025 |
| MBA Cleanpro Ltd | Administrative & support | 2025 |
| MBA Health Ltd | Health & social care | 2022 |