| Mininvest Limited | Mining & quarrying | 1996 |
| Minor Operations Ltd | Health & social care | 2025 |
| MIT Performance Ltd | Wholesale & retail | 2025 |
| Mitchell and Sanders Limited | Real estate | 2022 |
| MJ Boutique Ltd | Wholesale & retail | 2019 |
| MJ Business Coaching Ltd | Professional & scientific | 2011 |
| Mjant Limited | Professional & scientific | 2024 |
| MJB Motor Services Limited | Wholesale & retail | 2017 |
| MJC Heating and Plumbing Ltd | Construction | 2021 |
| MJN Limited | Wholesale & retail | 2018 |
| MK1 Tactical Ltd | Wholesale & retail | 2021 |
| MK3 Design Limited | Professional & scientific | 2017 |
| Mkcommercialservices Ltd | Wholesale & retail | 2024 |
| MKH Automotive Consultancy and Learning Solutions Limited | Education | 2015 |
| MLA Logistics Limited | Transport & logistics | 2008 |
| MLD Installation Ltd | Construction | 2018 |
| MLH1988 Ltd | Construction | 2015 |
| MM360 Ltd | Health & social care | 2020 |
| Moat House Care Home Limited | Health & social care | 1996 |
| Model BUS Federation | Other services | 2014 |
| Modern Aluminium Windows Limited | Manufacturing | 2024 |
| Modern Upvc Windows Limited | Real estate | 2017 |
| Modernity Ltd | Information & communication | 2024 |
| Moldova Service Limited | Transport & logistics | 2015 |
| Mono-Trail Limited | Manufacturing | 2008 |
| Monroe's Hair Limited | Other services | 2012 |
| Montage Scope Designs Limited | Professional & scientific | 2013 |
| Moore Bros Limited | Real estate | 2013 |
| Moore Earthwork Services Ltd | Construction | 2019 |
| Moore's of Burbage Ltd | Construction | 2008 |
| Moralis Grappling Academy Ltd | Education | 2023 |
| Morgan & Eeley Electrical Limited | Construction | 2023 |
| Morris Register Limited | Other services | 2017 |
| Mosi Limited | Wholesale & retail | 2016 |
| Mossala Ltd | Hospitality | 2025 |
| Motorcycle Select Ltd. | Wholesale & retail | 2016 |
| Move Assist Ltd | Administrative & support | 2025 |
| Move IT DAN Limited | Transport & logistics | 2025 |
| MQM Ltd | Manufacturing | 1995 |
| MRB Sound Ltd | Professional & scientific | 2024 |
| MRL Bearings Limited | Wholesale & retail | 2020 |
| MRL Midlands Limited | Wholesale & retail | 2009 |
| MRW Tech Ltd | Manufacturing | 2026 |
| MS Properties Hinckley Ltd | Real estate | 2024 |
| MS Shopsavvy Ltd | Wholesale & retail | 2026 |
| MSP Installations Limited | Construction | 2008 |
| MSP Plumbing Limited | Construction | 2021 |
| MTR (Machine Tool Repair) Ltd | Manufacturing | 2020 |
| Much Logistics Ltd | Transport & logistics | 2020 |
| Mulberry Square Limited | Professional & scientific | 2003 |
| Mulberry Tree Locums Limited | Professional & scientific | 2015 |
| Mulbrooke Advisory Limited | Financial services | 2024 |
| Mulbrooke House Limited | Professional & scientific | 2002 |
| Mulliganwilliams Accountancy Limited | Professional & scientific | 2014 |
| Mulliganwilliams Limited | Extraterritorial | 2009 |
| Multicare Medical Limited | Health & social care | 2013 |
| Munchkin Marketing Ltd | Wholesale & retail | 2019 |
| Murphy Construction & Civil Engineering Ltd | Professional & scientific | 2024 |
| Music Tech Hub Limited | Information & communication | 2026 |
| MVH Coaching and Consulting Ltd | Professional & scientific | 2023 |
| MW Accountants Limited | Professional & scientific | 2013 |
| MWC Search Limited | Administrative & support | 2007 |
| My Outdoor Oasis Ltd | Wholesale & retail | 2025 |
| Myshoprun Limited | Information & communication | 2025 |
| N Goodger Procurement Ltd | Professional & scientific | 2020 |
| N J & P J Gosling Ltd | Agriculture & fishing | 2020 |
| N J Assets Limited | Administrative & support | 2005 |
| N J Holdings Limited | Professional & scientific | 2005 |
| N J Screen Prints Limited | Manufacturing | 1991 |
| N W S Trading Limited | Hospitality | 2020 |
| N-Plas Living Ltd | Wholesale & retail | 2026 |
| N.A.I Transport Ltd | Transport & logistics | 2026 |
| Naas Corporation Limited | Energy | 1998 |
| National Democratic Ltd | Professional & scientific | 2025 |
| Natural Nursethetics Ltd | Health & social care | 2025 |
| Nautilus Steam Company Ltd | Manufacturing | 2022 |
| NB Automotive Ltd | Wholesale & retail | 2023 |
| NCS Building Contractors Ltd | Construction | 2009 |
| NDA Property Ltd | Real estate | 2013 |
| NE Therapy Ltd | Health & social care | 2026 |
| Neat Thinking Limited | Extraterritorial | 2009 |
| Neave Developments Limited | Real estate | 2016 |
| Need British Sign Language Limited | Education | 2011 |
| Neopress Limited | Manufacturing | 1999 |
| Neovia Logistics Services (U.K.) Limited | Transport & logistics | 1987 |
| Nerotrans Ltd | Transport & logistics | 2023 |
| Neuro Clinicians Ltd | Health & social care | 2026 |
| New Circle Events Limited | Health & social care | 2023 |
| New Fryways Ltd | Hospitality | 2014 |
| New Horizons Property Services Ltd | Construction | 2022 |
| New Look Detailing Ltd | Other services | 2013 |
| Newbold Grange Management Company Ltd | Households | 2020 |
| Newmax Holdings Limited | Financial services | 2024 |
| Newmax Precision Engineering Limited | Manufacturing | 1992 |
| Newton Electrical and Mechanical Ltd | Construction | 2006 |
| Nextgen Sports & Scholarship Ltd | Education | 2025 |
| Nextlevel Vehicle Movements Limited | Transport & logistics | 2020 |
| NFH Communications Limited | Administrative & support | 2019 |
| NHB Developments Limited | Professional & scientific | 2017 |
| Nicholson Stores Limited | Wholesale & retail | 2012 |