| MD Kitchens Limited | Manufacturing | 2017 |
| MDC Business Management Consultancy Ltd | Other services | 2021 |
| MED Plumbing & Heating Limited | Construction | 2003 |
| Media Village Audio Visual Ltd | Wholesale & retail | 2023 |
| Media Village Limited | Extraterritorial | 2016 |
| Mediscan Diagnostics Limited | Health & social care | 2025 |
| Mediterranean Kitchen Ltd | Hospitality | 2022 |
| Megaplex Limited | Arts & recreation | 2017 |
| Megowork Ltd | Information & communication | 2018 |
| MEL & Frank’S Barkery Ltd | Manufacturing | 2021 |
| Menara Analytics Limited | Administrative & support | 2016 |
| Menara Limited | Professional & scientific | 2009 |
| Mercer Print (UK) Limited | Manufacturing | 1993 |
| Mercury Petroleum Ltd | Wholesale & retail | 2009 |
| Mercyflow Innovations Ltd | Information & communication | 2025 |
| Merry DEN Care Limited | Health & social care | 2004 |
| Metalcraft Plastic Coatings Limited | Manufacturing | 1977 |
| MHS International (UK) Ltd | Wholesale & retail | 2013 |
| Michael Mellors Limited | Information & communication | 2013 |
| Michigan Pizza Limited | Wholesale & retail | 2024 |
| Micura Holdings Ltd | Financial services | 2018 |
| Miglior Automotive Limited | Administrative & support | 2020 |
| Milano Prestige Ltd | Wholesale & retail | 2025 |
| Mill Hill Associates Limited | Information & communication | 2018 |
| Miller & Brown Properties Limited | Real estate | 2007 |
| Mind and Beyond Ltd | Health & social care | 2024 |
| Minicabit Technologies Limited | Administrative & support | 2004 |
| Mint Rentals Ltd | Real estate | 2022 |
| Miro Products Limited | Wholesale & retail | 2018 |
| Missableu Ltd | Wholesale & retail | 2022 |
| Mitali (Accrington) Ltd | Hospitality | 2019 |
| Mitchell's Scaffolding Limited | Construction | 2003 |
| MJD Mechanics Ltd | Wholesale & retail | 2022 |
| MJM Joinery Services Ltd | Administrative & support | 2008 |
| MJN Electrical Ltd | Construction | 2021 |
| MJO Music Limited | Information & communication | 2014 |
| MJR Deliveries Ltd | Transport & logistics | 2025 |
| MK Marketplace Limited | Wholesale & retail | 2026 |
| Mkdp Properties Ltd | Real estate | 2015 |
| MKF Communications Ltd | Wholesale & retail | 2018 |
| Mlmc (Group) Limited | Financial services | 2025 |
| Mlmc (Holdings) Limited | Financial services | 2017 |
| Mlmc (Property) Ltd | Real estate | 2022 |
| MLS Scaffolding Inspection Ltd | Construction | 2019 |
| MMC Garages Ltd | Wholesale & retail | 2021 |
| MMD NW Ltd | Hospitality | 2023 |
| MMD Properties NW Ltd | Real estate | 2023 |
| MMK Developments Ltd | Construction | 2025 |
| MMS Traders Ltd | Wholesale & retail | 2024 |
| Mobiuk Ltd | Wholesale & retail | 2026 |
| MOC Builders Ltd | Construction | 2019 |
| Modee London Limited | Wholesale & retail | 2025 |
| Modesty Design NW Ltd | Wholesale & retail | 2026 |
| Momentum Network Solutions Ltd | Wholesale & retail | 2025 |
| Mondra Limited | Information & communication | 2007 |
| Moneyline Daffodil Limited | Financial services | 2024 |
| Moneyline Rose Limited | Financial services | 2024 |
| Moneyline Thistle Limited | Financial services | 2024 |
| Monjo Limited | Hospitality | 2023 |
| Monopoly Management Ltd | Real estate | 2016 |
| Montanaz Limited | Hospitality | 2026 |
| Monton Construction Limited | Construction | 2020 |
| Montvale Group Ltd | Administrative & support | 2025 |
| Moore View Cars Ltd | Wholesale & retail | 2025 |
| Mooresworth Leisure Ltd | Hospitality | 2019 |
| Moorfield Plant Services Ltd | Manufacturing | 2021 |
| Moorfield Remediation Limited | Water & waste | 2019 |
| Moorland Pharmacy Limited | Wholesale & retail | 2003 |
| Moosa Convenience Store Ltd | Wholesale & retail | 2025 |
| Morning Holding Group Limited | Financial services | 2025 |
| MOTIV8-LANCS CIC | Education | 2013 |
| Mouth Full of Sugar Limited | Manufacturing | 2020 |
| Movability and More Ltd | Wholesale & retail | 2015 |
| Moving People Ltd | Wholesale & retail | 2005 |
| MP Private Hire & Mini Buses Ltd | Transport & logistics | 2023 |
| MPC Mobiles Ltd | Wholesale & retail | 2026 |
| Mprx Consulting Ltd | Wholesale & retail | 2025 |
| MPV Group Limited | Professional & scientific | 2015 |
| MPV Investments Limited | Financial services | 2015 |
| MRM Deliveries Ltd | Transport & logistics | 2024 |
| MS Car Detailing Ltd | Wholesale & retail | 2025 |
| MSD Management Solutions Ltd | Construction | 2020 |
| MSE Enterprises Ltd | Professional & scientific | 2014 |
| MSF Furnishings Ltd | Other services | 2022 |
| MSR Prestige Ltd | Wholesale & retail | 2024 |
| MSW Digital Ltd | Professional & scientific | 2026 |
| MT Medix Ltd | Wholesale & retail | 2025 |
| Mueblin Ltd | Manufacturing | 2025 |
| Muhammad Yaqub Ltd | Wholesale & retail | 2025 |
| Murad Food Ltd | Hospitality | 2026 |
| Murphy's Plasterers Limited | Construction | 2015 |
| Musbury Brook Ltd | Construction | 2020 |
| Musbury Brook Properties Ltd | Real estate | 2021 |
| Muschamp Machine Services Limited | Manufacturing | 2000 |
| MUZ Motors Ltd | Wholesale & retail | 2025 |
| Mvba Limited | Hospitality | 2024 |
| MW Foster Engineering Limited | Administrative & support | 2014 |
| MW Properties 80 Ltd | Real estate | 2021 |
| My Abaseen Accrington Ltd | Hospitality | 2025 |
| My Global Aspirations Limited | Administrative & support | 2013 |