| MD Online Limited | Information & communication | 2012 |
| MDS Medical Limited | Wholesale & retail | 2010 |
| MEAT2MEETGRILLS Ltd | Hospitality | 2025 |
| Mecam Ltd | Manufacturing | 2024 |
| Mechengineering 24/7 Ltd | Manufacturing | 2025 |
| Medalist Ltd | Wholesale & retail | 2018 |
| Mede-Pod Limited | Information & communication | 2013 |
| Medhealth Care and Support Ltd | Public administration | 2021 |
| Median Healthcare Ltd | Health & social care | 2023 |
| Medical Diamonds Limited | Health & social care | 2025 |
| Medisinn Ltd | Wholesale & retail | 2026 |
| Medisphere Ltd | Health & social care | 2022 |
| Medlin Management Consultancy Ltd | Professional & scientific | 2019 |
| Medone Healthcare Limited | Administrative & support | 2023 |
| Medsurg Critical Care Limited | Health & social care | 2013 |
| MEE TV Ltd | Information & communication | 2018 |
| Meegan Engineering Services Ltd | Professional & scientific | 2025 |
| Mega Break Limited | Arts & recreation | 2016 |
| Megabyte Media Limited | Information & communication | 2014 |
| Megafilm Limited | Extraterritorial | 1986 |
| Megan Claire Limited | Manufacturing | 2015 |
| MEJ Consulting Services Ltd | Professional & scientific | 2025 |
| MEJ Group Properties Ltd | Real estate | 2023 |
| Melberg Ltd | Wholesale & retail | 2021 |
| Melitta Professional Coffee Solutions UK Ltd. | Wholesale & retail | 1990 |
| Melle Healthcare Ltd | Health & social care | 2025 |
| Melli Design Limited | Professional & scientific | 2010 |
| Melli UK Limited | Professional & scientific | 2010 |
| Melodo Online Limited | Wholesale & retail | 2024 |
| Melta Ltd | Transport & logistics | 2019 |
| Memor Construction Ltd | Construction | 2015 |
| Mems Automotive Ltd | Wholesale & retail | 2019 |
| Mercian Gate Limited | Public administration | 2024 |
| Mercury Harbour Ltd | Real estate | 2025 |
| Mercytan Limited | Health & social care | 2023 |
| Merestone Road 1970 Limited | Extraterritorial | 2014 |
| Meringues Bakery Ltd | Manufacturing | 2024 |
| Merla Vehicle Prep Ltd | Wholesale & retail | 2026 |
| Merley Holdings Limited | Financial services | 2020 |
| Metalfabs Limited | Manufacturing | 2003 |
| Metals Express Limited | Wholesale & retail | 1992 |
| Metaspan Ltd | Information & communication | 2021 |
| Metron Specialists Ltd | Wholesale & retail | 2012 |
| MF Commercial Ltd | Real estate | 2022 |
| MG Automotive Limited | Wholesale & retail | 2023 |
| MG Moto Ltd | Transport & logistics | 2016 |
| MGD Firstcare Limited | Health & social care | 2013 |
| MGF Holdings Ltd | Real estate | 2025 |
| Mgkb Group Ltd | Financial services | 2015 |
| MGS Garage Corby Ltd | Manufacturing | 2013 |
| MGS Imports Ltd | Wholesale & retail | 2022 |
| MGS Quality Cars Limited | Wholesale & retail | 2019 |
| MGS Realty Ltd | Real estate | 2018 |
| MH Valeting Services Ltd | Other services | 2017 |
| Mhazi PVT Ltd | Health & social care | 2021 |
| MHB Logistics Ltd. | Transport & logistics | 2018 |
| MHE Associates Limited | Professional & scientific | 2011 |
| MHP Engineering Limited | Administrative & support | 2018 |
| MI Richards Carpentry Limited | Construction | 2002 |
| MIA House Ltd | Real estate | 2024 |
| Miarta Ltd | Wholesale & retail | 2021 |
| Michael Edwards Productions Limited | Arts & recreation | 2000 |
| Michaels Haulage Limited | Transport & logistics | 2017 |
| Micho Ltd | Health & social care | 2015 |
| Micro Mall Ltd | Wholesale & retail | 2023 |
| Middle AGE Settlers Limited | Hospitality | 2009 |
| Midland Snacks Limited | Manufacturing | 2001 |
| Midlands Social Housing Group Ltd | Real estate | 2025 |
| Midlands Total Care Limited | Health & social care | 2020 |
| Midlands Vehicle Sales Limited | Wholesale & retail | 2024 |
| Midnightstore Ltd | Wholesale & retail | 2025 |
| Mihai Cercel Ltd | Wholesale & retail | 2024 |
| Mihalis Solutions Ltd | Transport & logistics | 2018 |
| Mikey Faulkner Limited | Professional & scientific | 2021 |
| Mikolo Limited | Transport & logistics | 2010 |
| Milex Engineering Ltd | Manufacturing | 2006 |
| Military Emporium Kettering Limited | Wholesale & retail | 2015 |
| Mill House Park Homes Limited | Real estate | 2009 |
| Mill Paddock Enterprises Limited | Professional & scientific | 2017 |
| Milla Ltd | Transport & logistics | 2026 |
| Mimulus Limited | Real estate | 2006 |
| Mina Solutions LLC Limited | Health & social care | 2023 |
| Mincheva Ltd | Education | 2025 |
| Mindent Dental LAB Ltd | Health & social care | 2009 |
| Mini SAM Ltd | Wholesale & retail | 2016 |
| Mint Publishing Limited | Information & communication | 2006 |
| Mintridge Consulting Limited | Administrative & support | 2005 |
| Mintridge Holdings Limited | Financial services | 2009 |
| Mintridge Holdings NO. 3 Ltd | Administrative & support | 2015 |
| Mintridge Investments Limited | Real estate | 1997 |
| Mintridge Natural Capital (Bedmond) Limited | Professional & scientific | 2022 |
| Mintridge Natural Capital (Glendon) Limited | Professional & scientific | 2022 |
| Mintridge Natural Capital (Purley Chase) Ltd | Professional & scientific | 2022 |
| Mintridge Natural Capital (Reading) Ltd | Professional & scientific | 2023 |
| Mintridge Natural Capital (Weedon Lois) Ltd | Professional & scientific | 2023 |
| Mintridge Natural Capital Ltd | Administrative & support | 2022 |
| Mirac Limited | Transport & logistics | 2016 |
| Mircea Freshpaint Ltd | Construction | 2026 |
| Mirror Moon Limited | Real estate | 2006 |
| Miruuuux’S Luxe Limited | Other services | 2025 |