| Mayan Market UK Ltd | Wholesale & retail | 2022 |
| Maycock Butchers Ltd | Wholesale & retail | 2026 |
| Mayden Limited | Financial services | 2026 |
| Mayer (UK) Ltd | Manufacturing | 2011 |
| Mayfair Carriages Limited | Wholesale & retail | 2017 |
| Mayfair Motorhaus Ltd | Wholesale & retail | 2025 |
| Mayfield Design & Planning Ltd | Professional & scientific | 2025 |
| Mayfield Mobile Home Park Limited | Real estate | 2023 |
| Mayfield Store Limited | Wholesale & retail | 2003 |
| Maynard Brown Limited | Real estate | 2020 |
| Mayne Company Limited | Manufacturing | 2018 |
| Mays Investments Limited | Real estate | 2004 |
| Maysiya Ltd | Health & social care | 2025 |
| MAZ Healthcare Limited | Health & social care | 2022 |
| MAZ Novok Ltd | Professional & scientific | 2025 |
| Mazhu GP Services Limited | Health & social care | 2013 |
| MB Commercial Consulting Ltd | Professional & scientific | 2020 |
| MB Drainage Limited | Water & waste | 2026 |
| MB Engraving Ltd | Other services | 2023 |
| MB Exec Travel Ltd | Transport & logistics | 2024 |
| MB Heating and Plumbing Limited | Construction | 2023 |
| MB Home Improvements Midlands Limited | Construction | 2021 |
| MB Reactive Maintenance Limited | Construction | 2026 |
| MB Topmost Ltd | Education | 2022 |
| MBE Capital Private Limited | Financial services | 2026 |
| Mbhella Properties UK Ltd | Real estate | 2025 |
| Mbj-Trans Limited | Other services | 2017 |
| MBM Media Limited | Wholesale & retail | 2025 |
| MBS Consult Limited | Professional & scientific | 2023 |
| MBS Derby Ltd | Transport & logistics | 2024 |
| Mbzx Limited | Hospitality | 2021 |
| MC Brick Cutting Services Limited | Manufacturing | 1999 |
| MC Troy Ltd | Hospitality | 2025 |
| MCA (UK) Limited | Wholesale & retail | 2012 |
| Mcadam Property Services Ltd | Real estate | 2023 |
| Mcaldar Properties UK Ltd | Real estate | 2026 |
| Mcanderson Associates Limited | Information & communication | 2022 |
| Mcandrew Property Developments Limited | Construction | 2009 |
| Mcandrew Utilities Limited | Construction | 2002 |
| Mcandrew Utilities Trustees Limited | Financial services | 2024 |
| MCB Software Limited | Information & communication | 2005 |
| MCC Car Sales Limited | Wholesale & retail | 2025 |
| MCC Infra Advisory Limited | Professional & scientific | 2013 |
| Mccabe Civils Ltd | Construction | 2021 |
| Mccallan Medical Limited | Manufacturing | 2010 |
| Mccarthy Accounting & Advisory Ltd | Professional & scientific | 2025 |
| Mccarthy Hill Family Office Ltd | Administrative & support | 2016 |
| Mccorquodale (Midlands) Limited | Other services | 2019 |
| Mccready Brickwork Ltd | Construction | 2021 |
| MCD Professional Services Limited | Information & communication | 2018 |
| MCD Property Investments Limited | Real estate | 2022 |
| Mcdaidengineering Limited | Construction | 2025 |
| Mcdermott Holding Group Ltd | Professional & scientific | 2019 |
| Mcdermott Investment Group Ltd | Financial services | 2019 |
| Mcdskymex Ltd | Real estate | 2012 |
| Mcgarrett Limited | Real estate | 2021 |
| Mcgee&Durraniconsulting Ltd | Professional & scientific | 2025 |
| Mcguire Building Services (Derby) Limited | Construction | 2007 |
| Mchs Holdings Limited | Professional & scientific | 2008 |
| Mchs Utilities Limited | Financial services | 2026 |
| Mcintyre Landlord and Building Services Ltd | Real estate | 2021 |
| MCK (UK) Limited | | 2009 |
| Mckastle Associates Limited | Professional & scientific | 2008 |
| Mckay-Boshell Ltd | Health & social care | 2019 |
| Mckenna and SON Ltd | Wholesale & retail | 2025 |
| Mckibben Ltd | Wholesale & retail | 2026 |
| Mckinsey Waterhouse Ltd | Professional & scientific | 2018 |
| MCL Live Action Limited | Wholesale & retail | 2026 |
| Mclaren Property Group Limited | Extraterritorial | 2019 |
| Mclure Associates Limited | Professional & scientific | 2016 |
| Mcmahon Projects Ltd | Other services | 2017 |
| Mcml - 1967 Limited | Administrative & support | 2014 |
| Mcneil Consulting and Property Services Limited | Information & communication | 2016 |
| Mcneill NDT Ltd | Manufacturing | 2016 |
| Mcpc Ltd | Construction | 2026 |
| Mcplas Ltd | Wholesale & retail | 2019 |
| MCQ Enterprises Ltd | Real estate | 2024 |
| Mcrb Limited | Professional & scientific | 2018 |
| Mcrock Berkeley & Lords Belgravia Ltd | Professional & scientific | 2026 |
| Mcturk Catering Supplies Limited | Manufacturing | 1994 |
| Mcturk Kebabs Ltd | Hospitality | 2015 |
| Mcturks Express Limited | Manufacturing | 2018 |
| MD Auto Traders Limited | Extraterritorial | 2018 |
| MD Cars (Derby) Ltd | Transport & logistics | 2018 |
| MD Conveyancing Limited | Professional & scientific | 2023 |
| MD Fencing (Derby) Ltd | Construction | 2021 |
| MD Psych Ltd | Education | 2025 |
| MD Smartrepair Ltd | Construction | 2017 |
| MD1718 Ltd | Hospitality | 2025 |
| MDA Plumbing Limited | Construction | 2018 |
| MDH UK Property Ltd | Real estate | 2025 |
| MDJ Manufacturing Limited | Manufacturing | 2009 |
| MDJ Project Support Ltd | Professional & scientific | 2026 |
| MDP Building Services Limited | Construction | 2019 |
| MDP365 Ltd | Information & communication | 2026 |
| MDS UK Holdings Limited | Financial services | 2023 |
| ME Myself Menopause CIC | Education | 2025 |
| ME Tech & Web Development Solutions Ltd | Information & communication | 2022 |
| ME16 Ltd | Arts & recreation | 2021 |
| MEA Beauty and Theraphy Limited | Other services | 2020 |