| Midas Touché Limited | Administrative & support | 2024 |
| Middle East & European Trading Ltd | Professional & scientific | 2020 |
| Middle East UK Advertising Limited | Information & communication | 2011 |
| Middleton Technology Limited | Information & communication | 2011 |
| Middlewich Limited | Professional & scientific | 2014 |
| Middlewich Physiotherapy & Sports Injury Clinic Limited | Health & social care | 2011 |
| Middytech Limited | Professional & scientific | 2024 |
| Midlands Private Neurophysiology Ltd | Health & social care | 2010 |
| Midlands Web Solutions Limited | Information & communication | 2004 |
| Midollo Limited | Professional & scientific | 2018 |
| Midspan Construction Ltd | Administrative & support | 2016 |
| Midvale Properties Ltd | Real estate | 2024 |
| Miex UK Limited | Construction | 2014 |
| MIFIT35 Ltd | Arts & recreation | 2017 |
| MIG Facades Limited | Construction | 2022 |
| MIG Mechanical Ltd | Construction | 2016 |
| MIG Medical Installations Ltd | Construction | 2010 |
| Mighty Salts Ltd | Manufacturing | 2024 |
| Mike Baker Consulting Limited | Professional & scientific | 2025 |
| Mike LEE Accounting and Consulting Limited | Professional & scientific | 2016 |
| Mike Perry Planning Services Limited | Professional & scientific | 2017 |
| Mike Thompson Associates Limited | Professional & scientific | 2015 |
| Mikiki Ltd | Professional & scientific | 2024 |
| Mila Decor Limited | Wholesale & retail | 2019 |
| Milano Tiling Ltd | Construction | 2024 |
| Milborne Properties Limited | Professional & scientific | 1988 |
| Milburg Ltd | Wholesale & retail | 2019 |
| Milemanor Limited | Real estate | 1984 |
| Milestone Aspirem Limited | Mining & quarrying | 2014 |
| Milestone Commercial Services Limited | Real estate | 2016 |
| Miletown Consulting Limited | Administrative & support | 2024 |
| Millennium 3 Design Studio Limited | Administrative & support | 2000 |
| Miller Estate Agents Limited | Professional & scientific | 1990 |
| Millers of Chester Limited | Real estate | 1953 |
| Millfield END Management Company Limited | Households | 2022 |
| Millforest Limited | Professional & scientific | 2025 |
| Millie Consultancy Limited | Administrative & support | 2010 |
| Milliken Defence Consultants Limited | Administrative & support | 2024 |
| Millington Paper Company Limited(The) | Professional & scientific | 1983 |
| Millington Property Development Ltd | Real estate | 2018 |
| Millington Slitting and Rewinding Company Limited(The) | Manufacturing | 1982 |
| Mills Mortgage Services Ltd | Financial services | 2024 |
| Millsdai Power Limited | Professional & scientific | 2023 |
| Millwala Limited | Administrative & support | 2015 |
| Milner Boardman Partnership Holdings Ltd | Financial services | 2017 |
| Milner Boardman Partnership Limited | Professional & scientific | 2010 |
| Milo Magic Limited | Professional & scientific | 2025 |
| Milton Construction and Property Limited | Professional & scientific | 2017 |
| Milton CP Limited | Construction | 2018 |
| Mima Propco Ltd | Construction | 2026 |
| Mind Experts Properties Ltd | Real estate | 2023 |
| Mind Remedies Limited | Administrative & support | 2012 |
| Mindblown Limited | Other services | 2023 |
| Mindful Data Limited | Information & communication | 2025 |
| Mindful Tech Company Limited | Information & communication | 2019 |
| Mindstream News Limited | Information & communication | 2023 |
| Mindstrong Consulting UK Limited | Information & communication | 2014 |
| Mindvale Ltd | Health & social care | 2026 |
| Mindwell Creative Ltd | Information & communication | 2025 |
| Minerva House Ltd | Real estate | 2013 |
| Minerva Place (Lymm) Management Company Limited | Real estate | 2022 |
| Minim Law Ltd | Professional & scientific | 2011 |
| Minimally Limited | Information & communication | 2016 |
| Mint Bridging (2) Limited | Financial services | 2020 |
| Mint Bridging Limited | Financial services | 2011 |
| Mint Clothing Ltd | Wholesale & retail | 2018 |
| Mint Property Finance Group Limited | Financial services | 2019 |
| Mint Property Finance Limited | Financial services | 2014 |
| Mint Property Trading Limited | Financial services | 2015 |
| Miplus Beauty Ltd | Other services | 2026 |
| Miragon Asset Management Limited | Financial services | 2019 |
| Miragon Capital Ltd | Professional & scientific | 2019 |
| Mirelo AI (UK) Ltd | Information & communication | 2026 |
| Mirivo Limited | Professional & scientific | 2026 |
| Mirmire Ltd | Information & communication | 2024 |
| Misp Holdings Limited | Wholesale & retail | 2019 |
| Missportrait Ltd | Wholesale & retail | 2015 |
| Mist Systems Ltd | Information & communication | 2004 |
| Mitchell Holding International Limited | Wholesale & retail | 2024 |
| Miteg Investments Ltd | Real estate | 2020 |
| Mitespring Ltd | Professional & scientific | 2014 |
| Mivv Limited | Professional & scientific | 2018 |
| Mixmups Entertainment Ltd | Information & communication | 2021 |
| Mizu Bathroom Design Ltd | Wholesale & retail | 2025 |
| MJ Beer Company Ltd | Hospitality | 2024 |
| MJ Consulting Services Limited | Professional & scientific | 2023 |
| MJ Lavin Ltd | Information & communication | 2023 |
| MJ Stanbrook Consulting Limited | Professional & scientific | 2023 |
| MJD Aviation Limited | Professional & scientific | 2025 |
| MJD Storage Solutions Limited | Other services | 2024 |
| MJF Design & Developments Ltd | Administrative & support | 2005 |
| MJF Solutions Limited | Professional & scientific | 2023 |
| MJG Chiropractic Limited | Health & social care | 2024 |
| MJH Software Solutions Ltd | Information & communication | 2019 |
| MJL Media & Education Ltd | Education | 2025 |
| Mjlm Consultancy Limited | Professional & scientific | 2023 |
| MJM QA Limited | Professional & scientific | 2021 |
| MJP Compliance Consulting Limited | Administrative & support | 2025 |
| Mjsm Properties Limited | Real estate | 2016 |
| MJT Consultancy Group Limited | Information & communication | 2020 |