| Milian Logistics Limited | Transport & logistics | 2025 |
| Miliki Ltd | Hospitality | 2024 |
| Milkcakesandmore Ltd | Hospitality | 2024 |
| Milkys Magic South Limited | Hospitality | 2022 |
| Mill Hill Garden and Allotment Society Limited | Other services | 2013 |
| Mill Yard Collective Limited | Real estate | 2011 |
| Millano Transports Ltd | Transport & logistics | 2024 |
| Millbrook Pension Management Limited | Other services | 1988 |
| Millennia Construction Ltd | Construction | 2009 |
| Millennium Consultants Ltd | Information & communication | 2020 |
| Millennium Friends UK Ltd | Construction | 2021 |
| Miller and Hall Ltd | Transport & logistics | 2019 |
| Miller Kent & Co Limited | Professional & scientific | 2014 |
| Millers View Statics Ltd | Hospitality | 2025 |
| Millfield Physio Centre Limited | Construction | 2022 |
| Millionwear Limited | Wholesale & retail | 2025 |
| Millsec Investment Group Ltd | Administrative & support | 2022 |
| Milton Connect Ltd | Real estate | 2015 |
| Milton Keynes Business School Limited | Real estate | 2000 |
| Milton Keynes MAK Limited | Hospitality | 2023 |
| Milton Motors One Ltd | Wholesale & retail | 2019 |
| Miltonbarn Limited | Professional & scientific | 1980 |
| MIM Consultancy Services Ltd | Professional & scientific | 2024 |
| Mimi Miesi Limited | Hospitality | 2013 |
| MIN Kang Ltd | Hospitality | 2014 |
| Minaar Limited | Wholesale & retail | 2026 |
| Minajewls Ltd | Administrative & support | 2026 |
| Minaraa Trading Ltd | Wholesale & retail | 2026 |
| Minasons Investments Ltd | Real estate | 2025 |
| Mind & YOU Therapy Ltd | Health & social care | 2026 |
| Mind Intelligence Limited | Professional & scientific | 2019 |
| Mind Pilot App Limited | Information & communication | 2026 |
| Mindbosslab Ltd | Administrative & support | 2026 |
| Mindland Ltd | Wholesale & retail | 2022 |
| Mindrecalls Ltd | Education | 2026 |
| Mindvera Ltd | Wholesale & retail | 2025 |
| Minera Holdings Limited | Real estate | 2021 |
| Mineral Economy Solution Limited | Professional & scientific | 2022 |
| Minhalibtahaj Ltd | Wholesale & retail | 2025 |
| Mini Champs Multi Sports Ltd | Education | 2025 |
| Mini One Plant Hire Limited | Agriculture & fishing | 2004 |
| Mini One Properties Limited | Real estate | 2007 |
| Mini Scholars Ltd | Health & social care | 2024 |
| Mini Stars Childcare Ltd | Other services | 2009 |
| Mini Steps Daycare Nursery Limited | Education | 2021 |
| Mini Treatz Ltd | Hospitality | 2026 |
| Minina Ltd | Manufacturing | 2025 |
| Minstart Ltd | Wholesale & retail | 2024 |
| Mint Property Maintenance Services Ltd | Administrative & support | 2022 |
| Mintbridge Retail Ltd | Wholesale & retail | 2025 |
| MIR Solution Keys Ltd | Administrative & support | 2014 |
| Miracle Group Limited | Information & communication | 2026 |
| Miracleselfgift Ltd | Information & communication | 2026 |
| Mirae Hiya Ltd | Information & communication | 2026 |
| Mirage Care Limited | Health & social care | 2018 |
| Miraj Consortium Ltd | Wholesale & retail | 2026 |
| Mirama Limited | Construction | 2024 |
| Miratrad Limited | Construction | 2009 |
| Mireecho Ltd | Information & communication | 2025 |
| Miretti UK Limited | Wholesale & retail | 2012 |
| Miro Builder's UK Limited | Construction | 2019 |
| Mirocin Ltd | Transport & logistics | 2019 |
| Mirpur Properties Limited | Real estate | 2023 |
| Mirrorx Tech Ltd | Wholesale & retail | 2025 |
| Miruna Logistics Limited | Transport & logistics | 2019 |
| Mirza Builders Luton Ltd | Construction | 2024 |
| Mirza Transport Management Limited | Professional & scientific | 2022 |
| MIS Gill Ltd | Wholesale & retail | 2025 |
| Misara International Ltd. | Wholesale & retail | 2015 |
| Mish Foods Limited | Professional & scientific | 2014 |
| Misha's Brows Bar Limited | Other services | 2016 |
| Misharu Ltd | Information & communication | 2003 |
| Mishi Enterprise Ltd | Administrative & support | 2021 |
| Mishiya Properties Limited | Real estate | 2019 |
| Mishkat Transport Ltd | Transport & logistics | 2022 |
| Miss Shine&Clean Limited | Administrative & support | 2017 |
| Missan Ltd | Manufacturing | 2018 |
| MISSION3D Creative Limited | Professional & scientific | 2023 |
| Mister Construction Ltd | Construction | 2024 |
| Mistletoe Court Management Company Limited | Households | 1990 |
| Mistry Investments Ltd | Construction | 2014 |
| Mitan Surfacing Limited | Construction | 2026 |
| Mitc Consulting Limited | Information & communication | 2019 |
| Mitchell Denyer Property Management Ltd | Extraterritorial | 2024 |
| Mitchell Technologies Limited | Information & communication | 2022 |
| MITEK-88 Ltd | Real estate | 2009 |
| Mithai Walla Ltd | Hospitality | 2024 |
| Mitisha Limited | Hospitality | 2021 |
| Mitu Carpentry&Joinery Ltd | Construction | 2016 |
| MIU Properties Ltd | Real estate | 2026 |
| MIU Suppliers Ltd | Wholesale & retail | 2025 |
| Mizans-Uk Ltd | Wholesale & retail | 2025 |
| Mizbaan Restaurant Ltd | Hospitality | 2026 |
| MJ Bullion Store Ltd | Wholesale & retail | 2018 |
| MJ Butt Sales and Lettings Ltd | Real estate | 2026 |
| MJ COX Electrical Services Limited | Construction | 2009 |
| MJ Fasttrack Limited | Transport & logistics | 2025 |
| MJ Home Improve Limited | Construction | 2023 |
| MJ Jacob Limited | Professional & scientific | 2025 |
| MJ LUX Ltd | Administrative & support | 2025 |