| MD Marco Screeding Limited | Construction | 2016 |
| MD17MARKETING Limited | Administrative & support | 2025 |
| MDB Solutions Limited | Information & communication | 2013 |
| MDG Supreme Limited | Professional & scientific | 2016 |
| MDL Construction Limited | Construction | 2026 |
| MDL Scenary Carpentry Ltd | Manufacturing | 2026 |
| Mead Motor Group Ltd | Wholesale & retail | 2024 |
| Mead Property Management Ltd | Real estate | 2020 |
| Mead Property Sales LLP | | 2026 |
| Meadfield Development Ltd | Construction | 2025 |
| Meadfield Kebab and Grill Ltd | Hospitality | 2025 |
| Meadfield Mews Limited | Households | 2013 |
| Meadowmach Rentals Ltd | Administrative & support | 2026 |
| Meadowvale Care (Bathgate) Limited | Health & social care | 2019 |
| Meads Limited(The) | Households | 1980 |
| Meah Services Limited | Public administration | 2018 |
| Mealbox Limited | Hospitality | 2000 |
| Mealglo Digital Limited | Information & communication | 2025 |
| Meat and Fish Supplies Ltd | Wholesale & retail | 2025 |
| Meat and Grill Ltd | Hospitality | 2025 |
| Mecca Estate Limited | Real estate | 2020 |
| Mecenas Legal Ltd | Information & communication | 2008 |
| Mechanical Arts Limited | Professional & scientific | 2008 |
| Mechora Group Ltd | Construction | 2025 |
| MED Support Ltd | Health & social care | 2016 |
| Medalchemy Limited | Health & social care | 2009 |
| Medanta Ltd | Health & social care | 2022 |
| Medfair Consultancy Ltd | Professional & scientific | 2022 |
| Medford Pharmaceuticals UK Limited | Wholesale & retail | 2023 |
| Medglobe Limited | Education | 2024 |
| Media Charged Limited | Professional & scientific | 2017 |
| Media Direction Limited | Professional & scientific | 2010 |
| Media One TEN Limited | Information & communication | 2010 |
| Media Perception Limited | Information & communication | 2004 |
| Media Today (Property) Limited | Real estate | 2022 |
| Medical Assessment UK Service Limited | Administrative & support | 2019 |
| Medical Staff Training Ltd | Education | 2020 |
| Medical Supreme Ltd | Administrative & support | 2024 |
| Medical Writing Consultancy & Services Ltd | Professional & scientific | 2025 |
| Medici Cosmo Services Limited | Health & social care | 2024 |
| Medicindia for YOU Limited | Professional & scientific | 2026 |
| Medico Training Limited | Education | 2019 |
| Medicsys Aylesbury Ltd | Real estate | 2025 |
| Medihub Healthcare Ltd | Wholesale & retail | 2022 |
| Medina Autos Ltd | Wholesale & retail | 2025 |
| Medina Hair & Beauty Ltd | Other services | 2022 |
| Medina Halal Meat Ltd | Wholesale & retail | 2024 |
| Medina Homes Ltd | Real estate | 2020 |
| Medinex Ltd | Wholesale & retail | 2026 |
| Medinova Medics Limited | Health & social care | 2011 |
| Mediref Consulting Ltd | Health & social care | 2016 |
| Meditand Ltd | Financial services | 2026 |
| Meditro Ltd | Information & communication | 2024 |
| Medroyce Ltd | Manufacturing | 2023 |
| MEDS2YOU (Coventry) Ltd | Wholesale & retail | 2026 |
| MEDS2YOU (Taunton) Ltd | Wholesale & retail | 2026 |
| MEDS2YOU(DUDLEY) Ltd | Wholesale & retail | 2026 |
| Medsearch Limited | Professional & scientific | 2012 |
| Medurol Ltd | Administrative & support | 2026 |
| Meedia Matrix Ltd | Professional & scientific | 2024 |
| Meer Contracting Ltd | Professional & scientific | 2026 |
| Meer Enterprises Ltd | Wholesale & retail | 2025 |
| Meerista Limited | Wholesale & retail | 2025 |
| Meewa Construction Ltd | Construction | 2023 |
| Mega ARC Electrical Ltd | Construction | 2024 |
| Mega Flooring Limited | Construction | 2025 |
| Mega Food and Drink Limited | Wholesale & retail | 2017 |
| Mega Global Ltd | Wholesale & retail | 2021 |
| Mega Haulage Limited | Transport & logistics | 2024 |
| Megan Contractors Limited | Construction | 2020 |
| Megan Estates Limited | Real estate | 2023 |
| Megan Services Ltd | Construction | 2008 |
| Megaslice LLP | | 2019 |
| Megasonic Services Limited | Transport & logistics | 2014 |
| Megastar UK Ltd | Construction | 2020 |
| Megawarne Consulting Ltd | Information & communication | 2012 |
| Meghna Tandoori Indian Restaurant Limited | Hospitality | 2004 |
| Megna Services Ltd | Wholesale & retail | 2022 |
| Mehad Ltd | Real estate | 2023 |
| Mehar KRI Ltd | Transport & logistics | 2024 |
| Mehar Limited | Extraterritorial | 2004 |
| Mehar's Route to Success Ltd | Education | 2026 |
| Mehr Beauty Bar Ltd | Other services | 2024 |
| Mehr Ltd | Administrative & support | 2023 |
| Mehra Investment Partners Ltd | Professional & scientific | 2025 |
| Mehran Altaf Ltd | Wholesale & retail | 2024 |
| Mehreen Properties UK Limited | Real estate | 2020 |
| Mehrose Construction and Roofing Limited | Construction | 2025 |
| Meiko UK Limited | Manufacturing | 1993 |
| Meka Group Ltd | Real estate | 2023 |
| Mekz Limited | Wholesale & retail | 1993 |
| Mele 4 Holdings Ltd | Financial services | 2026 |
| Mele 4 Property Ltd | Real estate | 2024 |
| Meliora International Ltd | Education | 2023 |
| Meller Holdings Limited | Financial services | 1983 |
| Melon Marketing Limited | Administrative & support | 2025 |
| Melron Ltd | Wholesale & retail | 2024 |
| Melron Property Ltd | Real estate | 2025 |
| Melsi Ltd | Construction | 2025 |
| Memento Plus Limited | Information & communication | 2021 |