| M a Foods (Bury) Limited | Hospitality | 2018 |
| M a Transport (BDF) Ltd | Transport & logistics | 2017 |
| M ALI Foods Ltd | Wholesale & retail | 2025 |
| M Azlan Ltd | Wholesale & retail | 2023 |
| M Brearley Motor Bodies Limited | Wholesale & retail | 2014 |
| M C & D Construction Limited | Construction | 2016 |
| M J Laycock Heavy Haulage Limited | Transport & logistics | 2020 |
| M J Wood Agencies Ltd | Professional & scientific | 2011 |
| M Leahy Property Limited | Real estate | 2018 |
| M R Caravans Limited | Wholesale & retail | 2011 |
| M T Leake Electrical Contracting Ltd | Construction | 2018 |
| M T Simpson Ltd | Construction | 2026 |
| M Taylor Installations Ltd | Construction | 2019 |
| M Tool Limited | Extraterritorial | 2012 |
| M W S Consult Ltd | Administrative & support | 2022 |
| M White Ductwork Installation Limited | Construction | 2013 |
| M Wright Property Portfolio Ltd | Real estate | 2022 |
| M&Co Property Limited | Real estate | 2023 |
| M&M Motors & Autobodies Ltd | Wholesale & retail | 2023 |
| M&M Property Works Ltd | Real estate | 2021 |
| M&O Services Ltd | Other services | 2018 |
| M&Q Collection Limited | Wholesale & retail | 2025 |
| M&S Global Properties Ltd | Real estate | 2024 |
| M&Sh Consultancy Ltd | Information & communication | 2011 |
| M-Tech Vehicles Ltd | Wholesale & retail | 2021 |
| M. J. Howard Technical Services Limited | Manufacturing | 1989 |
| M. K. Kitchen and Bedrooms Ltd | Manufacturing | 2021 |
| M. Mahad Limited | Health & social care | 2024 |
| M.A.K Recruitment Solutions Ltd | Administrative & support | 2025 |
| M.B Mobiles Ltd | Wholesale & retail | 2023 |
| M.C. LO SOL Ltd | Health & social care | 2004 |
| M.C. Motor Repairs Ltd | Wholesale & retail | 2003 |
| M.D. Homes Management Company Limited | Professional & scientific | 2004 |
| M.H.C.(Uk) Limited | Extraterritorial | 2011 |
| M.P. Motor Company (Holdings) Limited | Financial services | 2021 |
| M.P. Motors (MEP) Limited | Financial services | 2021 |
| M.R.B. Fabrications Limited | Manufacturing | 2002 |
| M.Rehman Scans Ltd | Health & social care | 2022 |
| M.S Tyres & Auto Care Limited | Wholesale & retail | 2026 |
| M.Shabir Management Consultancy Limited | Professional & scientific | 2018 |
| M1 Kicks Ltd | Wholesale & retail | 2022 |
| M24 Pest Control Ltd | Manufacturing | 2024 |
| M3 Electrical Engineering Ltd | Construction | 2025 |
| M60 Skip Hire Limited | Water & waste | 2010 |
| M65 Logistics Ltd | Transport & logistics | 2024 |
| M66 Car and Commercials Ltd | Wholesale & retail | 2021 |
| M66 Motors (Bury) Ltd | Wholesale & retail | 2024 |
| MA Smart Vend Ltd | Wholesale & retail | 2026 |
| Maalg Couriers Ltd | Transport & logistics | 2019 |
| MAC 2 Ltd | Construction | 2004 |
| MAC Automotive Group Ltd | Other services | 2019 |
| MAC Business Consulting Ltd | Professional & scientific | 2021 |
| MAC Electrical Services NW Ltd | Construction | 2026 |
| MAC Fleet Maintenance Ltd | Other services | 2019 |
| MAC Fuel Drains Ltd | Other services | 2019 |
| MAC Rescue & Recovery Ltd | Wholesale & retail | 2019 |
| Macan Smart Living Limited | Real estate | 2025 |
| Macclesfield Nature Restoration Project Ltd | Professional & scientific | 2025 |
| Mack NW Limited | Wholesale & retail | 2023 |
| Mackin and SON Limited | Real estate | 2025 |
| Macksoft Limited | Information & communication | 2008 |
| Mackys Kicks Ltd | Wholesale & retail | 2023 |
| Made Collective Limited | Professional & scientific | 2026 |
| Made R Holding Limited | Professional & scientific | 2026 |
| Maderunning Limited | Arts & recreation | 2026 |
| Madison Solutions WPC Ltd | Transport & logistics | 2019 |
| MAE Groundwork & Construction Ltd | Construction | 2015 |
| Maeme's Bolton Limited | Hospitality | 2023 |
| MAF Design and Build Limited | Extraterritorial | 2008 |
| Mag:Net Solutions Ltd | Information & communication | 2001 |
| Magic Frame Ltd | Wholesale & retail | 2019 |
| Magicuts Ltd | Other services | 2023 |
| Magnus Developments Ltd | Construction | 2026 |
| Magpark Property Ltd | Extraterritorial | 2024 |
| Mahar&Co Limited | Wholesale & retail | 2025 |
| Mahasal Luxe Ltd | Wholesale & retail | 2025 |
| Maher London Ltd | Wholesale & retail | 2017 |
| Mahon Web & Design Limited | Professional & scientific | 2024 |
| Maine Estates Limited | Households | 2021 |
| Mainline Menswear Holdings Limited | Professional & scientific | 2014 |
| Mainline Menswear Limited | Wholesale & retail | 1997 |
| Majas Solutions Limited | Administrative & support | 2015 |
| Majestic Motors MCR Ltd | Wholesale & retail | 2025 |
| Majestic Transport Services Ltd | Transport & logistics | 2023 |
| Majin BUU Ltd | Administrative & support | 2024 |
| Majjon Limited | Professional & scientific | 2008 |
| Majorbase Holdings Limited | Professional & scientific | 2016 |
| MAK Motor Traders Ltd | Wholesale & retail | 2016 |
| Maker Industrial Products Limited | Manufacturing | 2015 |
| Makers of History LLP | | 2013 |
| Makes Properties Ltd | Construction | 2025 |
| Makin and Waddock Property Ltd | Real estate | 2018 |
| Makin HAY Limited | Financial services | 2017 |
| Making Safeguarding Real Ltd | Health & social care | 2022 |
| Malamute Outdoor Clothing and Equipment Ltd | Wholesale & retail | 2016 |
| Malebox Ltd | Wholesale & retail | 2024 |
| Mama Ann's Cafe Ltd | Hospitality | 2025 |
| Mama MIA Pizza Heywood Ltd | Hospitality | 2024 |
| Mambique Joinery Ltd | Construction | 2012 |
| Mamorisk Ltd | Wholesale & retail | 2018 |