| Mindgap Investments Limited | Financial services | 2018 |
| Minibus Driver Assessment Ltd | Education | 2016 |
| Mint Cake Medic Ltd | Health & social care | 2026 |
| Miros Express Ltd | Transport & logistics | 2019 |
| Mistral Services Limited | Other services | 2017 |
| MJ Coatings Limited | Manufacturing | 2012 |
| MJB Farming Limited | Agriculture & fishing | 2025 |
| MJB Jarvis Ltd | Real estate | 2017 |
| Mjsw Ltd | Wholesale & retail | 2015 |
| MKW Welding and Fabrication Services Limited | Manufacturing | 2025 |
| Mlex UK Designs Ltd | Professional & scientific | 2022 |
| MM (GB) Ltd | Information & communication | 2011 |
| Mmbs Services Limited | Financial services | 2006 |
| Mobile Autocare Ltd | Professional & scientific | 2024 |
| Mobile Unit Sales Limited | Manufacturing | 2020 |
| Mobius AI Limited | Information & communication | 2024 |
| Moch Consulting Ltd | Professional & scientific | 2025 |
| Modern Methods Marketing Limited | Education | 2011 |
| Modern Outlook Furniture Ltd | Wholesale & retail | 2021 |
| Modulus Digital Ltd | Transport & logistics | 2023 |
| Mofftec Ltd | Wholesale & retail | 2015 |
| Mofftec Properties Limited | Wholesale & retail | 2026 |
| Monart & Holloway Limited | Hospitality | 2023 |
| Montamedia Limited | Professional & scientific | 2008 |
| MOPCO400 Limited | Manufacturing | 2025 |
| Morebang Ltd | Professional & scientific | 2026 |
| Morgan Brothers Landscaping and Decorating Ltd | Construction | 2021 |
| Morley Briggs Developments Limited | Construction | 2025 |
| Morley Farming Limited | Agriculture & fishing | 2012 |
| Morley Land and Property Limited | Real estate | 2012 |
| Moss Turkish Barbers Ltd | Other services | 2023 |
| Motion 8 Prestige Cars Limited | Wholesale & retail | 2012 |
| Motion Dance Company Limited | Arts & recreation | 2011 |
| Moto Movers Limited | Transport & logistics | 2020 |
| Moto Trade Bikes Limited | Wholesale & retail | 2021 |
| Mousley Family Funerals Ltd | Other services | 2012 |
| Movewrite Limited | Information & communication | 2006 |
| Mowbray Contractors Ltd | Construction | 2022 |
| Mowbray Education Trust Limited | Education | 2011 |
| Mowbray Education Trust Services Limited | Education | 2015 |
| Mowbray Enterprise Management Ltd. | Transport & logistics | 2013 |
| Mowbray Metals Ltd | Other services | 2026 |
| Mowbray Pizza Ltd | Hospitality | 2025 |
| Mowbray Plumbing & Heating Ltd | Construction | 2024 |
| Mowbray Weathering Solutions Limited | Construction | 2024 |
| Moycare Limited | Real estate | 2022 |
| MRH Agri Limited | Agriculture & fishing | 2012 |
| MRS Hire Ltd | Administrative & support | 2013 |
| Mrsjk Services Limited | Wholesale & retail | 2024 |
| MSB Melton Limited | Hospitality | 2021 |
| MSN Display Limited | Construction | 2008 |
| Multimedix Limited | Professional & scientific | 2022 |
| Munro Saddle Fitting Services Ltd | Arts & recreation | 2025 |
| Murrays & Moores Respite Care Ltd | Health & social care | 2022 |
| MW Mechanical Services Ltd | Wholesale & retail | 2022 |
| My Consortium Limited | Other services | 2009 |
| My Favourite Brownie Ltd | Manufacturing | 2025 |
| My Feed Social Ltd | Information & communication | 2024 |
| My First Mountain Ltd | Administrative & support | 2018 |
| My Heating Services Limited | Extraterritorial | 2025 |
| My Own Store Limited | Real estate | 2020 |
| My Probate Guide Limited | Professional & scientific | 2020 |
| My PUB Limited | Hospitality | 2004 |
| Myriad CEG Group Limited | Administrative & support | 2009 |
| Myriad Heat and Power Products Ltd | Manufacturing | 2011 |
| N & T Composites Limited | Manufacturing | 2019 |
| N a O'Sullivan Ltd | Construction | 2017 |
| N B Melton Ltd | Wholesale & retail | 2024 |
| N H Services Limited | Construction | 2007 |
| N P Taylor Limited | Professional & scientific | 2015 |
| N&J Plumbing & Heating Services Limited | Construction | 2005 |
| N.A. Vines & SON Limited | Construction | 2003 |
| N.D. Connors Farms Limited | Agriculture & fishing | 1976 |
| N@T Technical Services Limited | Professional & scientific | 2024 |
| Naomi Irvine Ltd | Administrative & support | 2017 |
| Nash Creative Limited | Professional & scientific | 2023 |
| Nasriel Ltd | Information & communication | 2026 |
| National Futsal Series (NFS) Ltd | Arts & recreation | 2020 |
| National Quality Accommodation Ltd | Construction | 2025 |
| Naturally Grounded Nutrition Ltd | Hospitality | 2018 |
| Ndaba Limited | Information & communication | 2007 |
| Ndaba Support Services Ltd | Information & communication | 2016 |
| Neil Eaves Ltd | Education | 2018 |
| Neil Pidgeon Limited | Professional & scientific | 2011 |
| Neon Innovation Ltd | Professional & scientific | 2024 |
| Nepal Dine Melton Mowbray Ltd | Hospitality | 2025 |
| NET Accountancy Solutions Limited | Professional & scientific | 2017 |
| Neurovecta Ltd | Information & communication | 2025 |
| New Air Repair Ltd | Construction | 2024 |
| New Leaf Triangle C.I.C. | Education | 2014 |
| New Leaf Triangle Education Limited | Education | 2025 |
| New Spittles Green Energy Limited | Energy | 2017 |
| New Steel Solutions Ltd | Manufacturing | 2013 |
| Newborn Packaging Limited | Wholesale & retail | 2011 |
| Newbridge Residential (2) Limited | Real estate | 2021 |
| Newham Services Limited | Real estate | 2020 |
| Newton Technologies Ltd | Professional & scientific | 2024 |
| Nexa Finance Limited | Financial services | 2006 |
| Nexa Lending & Security Services Ltd | Financial services | 2020 |
| Nexia Holdings UK Ltd | Financial services | 2016 |