| Maccom Automation Limited | Manufacturing | 2013 |
| Maccom Services Limited | Manufacturing | 2019 |
| Madeleine House RTM Company Limited | Households | 2025 |
| Magmoz Ltd | Health & social care | 2020 |
| Magnolias (Stourport) Limited | Wholesale & retail | 2023 |
| Maison Estates Limited | Real estate | 2012 |
| Maison Group Holdings Limited | Real estate | 2021 |
| MAK Recruitment Ltd | Administrative & support | 2018 |
| Makaz Solutions Ltd | Professional & scientific | 2014 |
| Make Your Move Property Ltd | Real estate | 2024 |
| Making Ideas Work Ltd | Information & communication | 2017 |
| Mallu Motors Ltd | Wholesale & retail | 2026 |
| Malt Harbour Ltd | Information & communication | 2023 |
| MAN on the Move Limited | Transport & logistics | 2026 |
| Mane Realty Ltd | Construction | 2025 |
| Mann Stores Ltd | Wholesale & retail | 2011 |
| Manor Court Stone Limited | Households | 2015 |
| Manor Oak Residential Properties Limited | Real estate | 1988 |
| Manorfields Ltd | Real estate | 2011 |
| Manrizore Ltd | Administrative & support | 2024 |
| Manser Investments Limited | Real estate | 2023 |
| Manufacturing Productivity Improvements Limited | Professional & scientific | 1995 |
| Maple Aion Limited | Construction | 1997 |
| Maple Bewdley Limited | Real estate | 2017 |
| Maple Construction Group Limited | Financial services | 2015 |
| Mapnovabin Ltd | Wholesale & retail | 2018 |
| Maps Cellular Global Ltd | Information & communication | 2020 |
| Maps Cellular Limited | Wholesale & retail | 2020 |
| Maps Critical Infrastructure Limited Limited | Administrative & support | 2011 |
| Maps Defence Global Ltd | Public administration | 2020 |
| Maps Defence Ltd | Public administration | 2020 |
| Maps Holdings Limited | Professional & scientific | 2013 |
| Maps Solutions Europe Limited | Administrative & support | 2012 |
| Maps Wireless Limited | Administrative & support | 2012 |
| Marc Stones Limited | Manufacturing | 2019 |
| Maredi Building Solutions Ltd | Construction | 2024 |
| Maria RUS Ltd | Health & social care | 2020 |
| Marius BUS Transport Ltd | Transport & logistics | 2025 |
| Mark Jones Property Letting Limited | Real estate | 2010 |
| Mark Palmer Plumbing & Heating Limited | Construction | 2008 |
| Mark Pearce Haulage Ltd | Transport & logistics | 2020 |
| Mark Senter Limited | Construction | 2018 |
| Mark Vernon Limited | Manufacturing | 2014 |
| Marlpool Court Limited | Real estate | 1998 |
| Marlpool Diner Limited | Hospitality | 2023 |
| Marshall Structures Ltd | Professional & scientific | 2011 |
| Marshall Taylor's of Kidderminster Limited | Wholesale & retail | 2020 |
| Martinstown Ltd | Administrative & support | 2022 |
| Mary Martin Enterprise Ltd | Real estate | 2014 |
| Maryland Group Limited | Administrative & support | 1989 |
| Masons Platforms Ltd | Administrative & support | 2026 |
| Matrix Professional Audio Limited | Manufacturing | 2020 |
| Matthew Barry Ltd | Transport & logistics | 2026 |
| Matthew Nicholas Property Limited | Real estate | 2002 |
| MAW IT Consultancy Limited | Financial services | 2012 |
| Mawley Holdings Limited | Professional & scientific | 2002 |
| Mawley Matt Ltd | Wholesale & retail | 2021 |
| Maximum Creations Ltd | Construction | 2024 |
| Maximus Consultants Limited | Financial services | 2014 |
| Maxwhimpod Ltd | Wholesale & retail | 2018 |
| Maya's Delicious Food Ltd | Manufacturing | 2025 |
| Mayfield Court (Kidderminster) Management Limited | Households | 1993 |
| Mayfield Honey Ltd | Agriculture & fishing | 2021 |
| Mayflower Foodie Limited | Hospitality | 2024 |
| Mayo's Auto Centre Limited | Wholesale & retail | 2016 |
| Mayo's Car & Commercial Limited | Wholesale & retail | 2015 |
| Mayson & Sons Ltd | Construction | 2019 |
| MB Paraplanning Solutions Ltd | Financial services | 2020 |
| MB Plastering Contractors Limited | Construction | 2019 |
| MB Solar Ltd | Construction | 2021 |
| Mbai Systems Ltd | Information & communication | 2025 |
| MBD Trans Ltd | Transport & logistics | 2025 |
| Mccarron Assets Protection Solutions Ltd. | Administrative & support | 2014 |
| Mccormack Building Consultancy Limited | Construction | 2018 |
| MCF Complex Limited | Real estate | 1986 |
| MCF Estates Limited | Real estate | 2026 |
| MDS Power Engineering Ltd | Manufacturing | 2017 |
| Meadow Valley Limited | Manufacturing | 2019 |
| Meadowmill Properties Limited | Households | 2024 |
| MEB IT Ltd | Information & communication | 2015 |
| Medal Locator CIC | Administrative & support | 2020 |
| Mederavita Ltd | Manufacturing | 2025 |
| MEDIADIVISION2013 Ltd | Information & communication | 2013 |
| Medicplus Ltd | Extraterritorial | 2010 |
| Megareg Limited | Professional & scientific | 2022 |
| Mehaj Consultancy Limited | Health & social care | 2014 |
| Melanoid Ltd | Information & communication | 2014 |
| Melconzy Ltd | Hospitality | 2023 |
| Melopize Ltd | Administrative & support | 2024 |
| Melt Software Solutions Limited | Information & communication | 2025 |
| Melvin While Management Limited | Construction | 2021 |
| Melwood Property Management Limited | Real estate | 2020 |
| Meninaria Ltd | Health & social care | 2020 |
| Mentalfit Martial Arts LLP | | 2024 |
| Mentinquone Ltd | Administrative & support | 2024 |
| Meozilmer Ltd | Wholesale & retail | 2021 |
| Mercavo Global Traders Ltd | Wholesale & retail | 2026 |
| Mercian Court RTM Company Limited | Households | 2010 |
| Mereside Projects Limited | Professional & scientific | 2023 |
| Merlin Catering Limited | Hospitality | 2007 |