| Mark King Quality Pharma Ltd | Professional & scientific | 2024 |
| Mark L Riley Transport Limited | Transport & logistics | 2025 |
| Marlborough Estates (Sandbach) Limited | Real estate | 2012 |
| Marrow Developments Ltd | Real estate | 2025 |
| Martech Services Ltd | Information & communication | 2022 |
| Martree Residents Group Limited | Households | 2022 |
| Martrim Limited | Wholesale & retail | 1998 |
| Mason Homes Ltd | Real estate | 2018 |
| Matrix 4.TV Limited | Wholesale & retail | 2018 |
| Matrix Hair Salon Ltd | Other services | 2014 |
| Matthew Hayward Architects Limited | Professional & scientific | 2013 |
| Maxibuild Limited | Construction | 1980 |
| MC College Alumni UK Ltd | Other services | 2019 |
| MCB Highway Solutions Ltd | Professional & scientific | 2023 |
| MCC Plant Hire Limited | Administrative & support | 2016 |
| Mckmurray Services Ltd | Households | 2025 |
| Mckown Magalhaes Consulting Limited | Professional & scientific | 2007 |
| MCM Contract Solutions Limited | Construction | 2024 |
| Mcmahon Transport Ltd | Transport & logistics | 2025 |
| MCS Commissioning Ltd | Professional & scientific | 2023 |
| MDP Handling Limited | Professional & scientific | 2024 |
| ME 2 Yang Ltd | Hospitality | 2023 |
| Meadows & Partners Ltd | Professional & scientific | 2025 |
| Meadowside Ltd | Real estate | 2022 |
| Meadowside Rentals Limited | Real estate | 2024 |
| Meadowside Sevenoaks Ltd | Administrative & support | 2024 |
| Mearlag Limited | Professional & scientific | 2009 |
| Media Cat Limited | Other services | 2023 |
| Megawatt Project Solutions Limited | Administrative & support | 2017 |
| Melia and Cheung Ltd | Professional & scientific | 2011 |
| Melia Cheung (Manchester) Limited | Professional & scientific | 2015 |
| Mellow Digital Growth Agency Ltd | Information & communication | 2026 |
| Melody Corporation Limited | Administrative & support | 2015 |
| Menu App Ltd | Other services | 2023 |
| MER Engineering Solutions Ltd | Professional & scientific | 2024 |
| Mercia Tree Care Ltd | Administrative & support | 2019 |
| Merrill Construction Ltd | Construction | 2011 |
| MET Investments Limited | Real estate | 2017 |
| MH Financial Ltd | Financial services | 2008 |
| Michael Jones Chartered Forensic Fire Electrical Limited | Information & communication | 2019 |
| Midas CC Projects Limited | Construction | 2016 |
| Midas Construction (Cheshire) Limited | Construction | 2008 |
| Midland Inns Enterprises Limited | Hospitality | 2019 |
| Midlands Vape Supplies Ltd | Wholesale & retail | 2025 |
| Milisnehal Construction Ltd | Construction | 2017 |
| Military Arms Ltd | Hospitality | 2024 |
| Millbuck Limited | Administrative & support | 2013 |
| Millstream Yield Ltd | Health & social care | 2014 |
| Millys Garage Ltd | Wholesale & retail | 2020 |
| Minblast Ltd | Mining & quarrying | 2014 |
| Mindful Transformations Limited | Information & communication | 2015 |
| Mineral & Mining Consultancy Ltd | Professional & scientific | 2019 |
| Mint Events Limited | Administrative & support | 2005 |
| MIX Broadcast Limited | Information & communication | 2017 |
| Mksw Limited | Other services | 2016 |
| Mode Projects (NW) Ltd | Construction | 2021 |
| Modsec Investments Ltd | Financial services | 2024 |
| Mojo Tanning Studio Ltd | Other services | 2018 |
| MOL Associates Ltd | Manufacturing | 2019 |
| Monika Palka Hospitality Limited | Hospitality | 2019 |
| Monster Print Group Ltd | Manufacturing | 2019 |
| Moravia Steel UK Limited | Wholesale & retail | 2000 |
| Morris Agri Ltd | Manufacturing | 2021 |
| Mounfield Property Solutions Limited | Real estate | 2025 |
| Mountain Heather Holdings Limited | Financial services | 2012 |
| Mountain Heather Hotels Limited | Extraterritorial | 2023 |
| Mountain Heather Investments and Developments Ltd | Financial services | 2025 |
| Mourne Landscapes & Design Ltd | Administrative & support | 2023 |
| MPM Scales LLP | | 2012 |
| MPR Plumbing & Heating Services Ltd | Construction | 2026 |
| MRV Engineering Ltd | Professional & scientific | 2022 |
| MS Plast Limited | Professional & scientific | 2010 |
| MSD Driveways Ltd | Construction | 2023 |
| MT Commercial Vehicles Limited | Wholesale & retail | 2017 |
| MTM Building Services Ltd | Construction | 2026 |
| Muju Ltd | Manufacturing | 2017 |
| Multiple Solutions Limited | Construction | 2018 |
| Multisensory Ltd | Manufacturing | 2024 |
| Multistar Container Transport Limited | Administrative & support | 1986 |
| Munna Babu Infinity Hospitality Ltd | Hospitality | 2024 |
| Mustard Seed Marketing Limited | Information & communication | 2013 |
| MVL Services Limited | Construction | 2006 |
| MVP Tankhaul Ltd | Transport & logistics | 2016 |
| MYALUJOK9 Services Limited | Agriculture & fishing | 2021 |
| Mypotential Ltd | Wholesale & retail | 2025 |
| Mytoolkit Ltd | Wholesale & retail | 2012 |
| Namor Developments Ltd | Construction | 2019 |
| Nantwich Vipers Ltd | Arts & recreation | 2024 |
| Naylor Budd Education Limited | Professional & scientific | 2004 |
| NE Truck and Trailer Ltd | Wholesale & retail | 2022 |
| Neighbour Legal Limited | Professional & scientific | 2019 |
| Nemesiscollectables Ltd | Wholesale & retail | 2025 |
| Networks Resourcing Limited | Administrative & support | 2016 |
| Neux Renovations Ltd | Construction | 2022 |
| Neve Minton Marketing & Consultancy Ltd | Wholesale & retail | 2024 |
| New Leadership Network Limited | Education | 2013 |
| New Street Developments Elworth Limited | Construction | 2020 |
| New World Restaurant Holdings Ltd | Hospitality | 2018 |
| Newenco Limited | Manufacturing | 2011 |
| Newfield Fabrications Company Limited | Manufacturing | 1965 |