| Mark Philip Cronin Limited | Extraterritorial | 2025 |
| Mark Steeles Developments Ltd | Construction | 2008 |
| Mark Tinkler Simple Window Solutions Ltd | Construction | 2013 |
| Marketlaw Ltd | Professional & scientific | 2003 |
| Marnic Technology Limited | Manufacturing | 1992 |
| Maro Pure Ltd | Administrative & support | 2025 |
| Marrakech Bazar Ltd | Administrative & support | 2018 |
| Marron Accounts Limited | Professional & scientific | 2023 |
| Marsha Limited | Real estate | 2025 |
| Marsha Lloyd Hairdressing Limited | Other services | 2011 |
| Marshall Partners Ltd | Professional & scientific | 2015 |
| Marshall's Garage (Fallowfield) Ltd | Wholesale & retail | 2015 |
| Martin Morris Consulting Limited | Construction | 2015 |
| Marvellous Security Services Limited | Administrative & support | 2016 |
| Marvelous Properties Limited | Real estate | 2012 |
| Mary Kitty Limited | Financial services | 2023 |
| Mary Sophora Ltd | Wholesale & retail | 2025 |
| Maryam Ellouis Limited | Wholesale & retail | 2022 |
| Maryland Securities Group Limited | Professional & scientific | 2022 |
| Maryland Securities Investments Ltd | Real estate | 2005 |
| Maryland Securities Limited | Real estate | 1986 |
| MAS (NW) Limited | Construction | 2023 |
| MAS Optometry Ltd | Wholesale & retail | 2025 |
| MAS Property Ventures Limited | Real estate | 2019 |
| Masaat London Ltd | Wholesale & retail | 2026 |
| Masair Group Limited | Wholesale & retail | 2025 |
| Mass Property & Management Ltd | Real estate | 2018 |
| Massala Spice Limited | Hospitality | 2018 |
| Mast Architecture Limited | Professional & scientific | 2022 |
| Master Rates International Ltd | Professional & scientific | 2020 |
| Master Rates POS Ltd | Information & communication | 2020 |
| Masters Rates Ltd | Professional & scientific | 2018 |
| Mata Jiwa Fineart Limited | Wholesale & retail | 2023 |
| Matcha LAB Ltd | Hospitality | 2025 |
| Matchdayevents Ltd | Administrative & support | 2026 |
| Mathers Printing Limited | Manufacturing | 2019 |
| Mathsyava Consulting Services Ltd | Information & communication | 2018 |
| Matildas Animal Feed and Bedding Ltd | Wholesale & retail | 2026 |
| Matos Cleaning Ltd | Administrative & support | 2025 |
| Matrec (Developments) Limited | Construction | 1978 |
| Matt I Pharma Ltd | Wholesale & retail | 2024 |
| Matt Windsor Ltd | Arts & recreation | 2012 |
| Mattard Trade Co., Limited | Wholesale & retail | 2025 |
| Matteve Limited | Financial services | 2013 |
| Mattie Goodvibes Limited | Information & communication | 2025 |
| Maturo Property Ltd | Real estate | 2024 |
| Maunder Homes Ltd | Real estate | 2025 |
| Maurice Kilbride (Residential Sales) Limited | Real estate | 2008 |
| Mawlana UK Ltd | Wholesale & retail | 2023 |
| MAX Construction Limited | Construction | 2026 |
| MAY Nineteen Services Limited | Administrative & support | 2024 |
| Maya Emporium Limited | Wholesale & retail | 2022 |
| Mayer Textile Limited | Wholesale & retail | 2022 |
| Mayfair Media Production Ltd | Information & communication | 2023 |
| Mayfield House (Didsbury) Limited | Households | 1997 |
| Maze & Tonic CIC | Health & social care | 2024 |
| MB & AB Limited | Health & social care | 2024 |
| MB Education & Translation Services Ltd | Professional & scientific | 2020 |
| MB Medisport Limited | Health & social care | 2020 |
| MB Solutions Group Limited | Professional & scientific | 2022 |
| MBG Brickwork Limited | Construction | 2018 |
| MBK Medicals Ltd | Health & social care | 2020 |
| MC Advisory Limited | Professional & scientific | 2013 |
| MC Aviation Services Limited | Manufacturing | 2022 |
| MC Fire Group Ltd | Public administration | 2025 |
| MC Furniture and Design Ltd | Wholesale & retail | 2021 |
| MC Property Refurbs Limited | Construction | 2022 |
| MC Residential Ltd | Real estate | 2024 |
| MCA Fitness and Events Ltd | Arts & recreation | 2022 |
| Mccracken Marketing Ltd | Professional & scientific | 2025 |
| Mccumesky Floor's Ltd | Construction | 2025 |
| Mcdermott's Electrical Services Limited | Construction | 2017 |
| Mcdonald Brothers Limited | Real estate | 2025 |
| Mcevans Properties Ltd | Construction | 2024 |
| MCG Consulting Services Ltd | Information & communication | 2018 |
| MCN Grafix Ltd | Wholesale & retail | 2024 |
| Mcneil IT Services Co Ltd | Information & communication | 2024 |
| Mcphee Printing Ltd | Manufacturing | 2013 |
| MCR Drivers Ltd | Transport & logistics | 2025 |
| MCR Enterprises Group Ltd | Wholesale & retail | 2020 |
| MCR Executive Chauffeurs Ltd | Transport & logistics | 2020 |
| MCR Surfacing Ltd | Construction | 2026 |
| MCR1 Ltd | Real estate | 2019 |
| Mcrheat Limited | Construction | 2025 |
| MD GAS Services North West Limited | Construction | 2015 |
| MD Murray IT Limited | Information & communication | 2016 |
| MD Roofing Company MCR Limited | Extraterritorial | 2025 |
| MDM Print Packaging Ltd | Manufacturing | 2023 |
| MDP Builds Ltd | Manufacturing | 2026 |
| Meade Holdings Ltd | Real estate | 2017 |
| Meadows and Meanders CIC | Professional & scientific | 2024 |
| Meadowvale (Chorlton) Property Management Company Limited | Households | 2004 |
| Meadway Homestays Ltd | Real estate | 2025 |
| Mealab Ltd | Hospitality | 2025 |
| Medallion Merchandise Limited | Wholesale & retail | 1999 |
| Medcon Support Limited | Administrative & support | 2022 |
| Media Factory Limited | Information & communication | 2013 |
| Media Image Ltd | Manufacturing | 2005 |
| Medics Events Ltd | Other services | 2018 |
| Medicus Legal Limited | Professional & scientific | 2014 |