| M & D Moore Ltd | Real estate | 2025 |
| M and M (Tunbridge Wells) Limited | Health & social care | 2020 |
| M Hibbert Consultancy Limited | Administrative & support | 2010 |
| M J Morgan Properties Limited | Real estate | 2021 |
| M J Wright Plastering Limited | Construction | 2021 |
| M Lord Ltd | Professional & scientific | 2018 |
| M R Garland Limited | Professional & scientific | 2002 |
| M T B Computer Services Limited | Information & communication | 1999 |
| M T S Design Limited | Professional & scientific | 2017 |
| M W Floorz Limited | Construction | 2003 |
| M&P Care Services Limited | Health & social care | 2020 |
| M. Iles Contractor (Kent) Ltd | Construction | 2015 |
| M. J. Oley Building Services Limited | Construction | 2003 |
| M.D.V. Limited | Manufacturing | 1985 |
| M.E.Willis Plastering Contractor Ltd | Construction | 2023 |
| M.F.C. International Limited | Manufacturing | 1959 |
| M.J.K. Limited | Administrative & support | 1998 |
| M.R.G Home Improvements Limited | Construction | 2019 |
| M2M Fenders Limited | Administrative & support | 2006 |
| M365 Experts Ltd | Information & communication | 2025 |
| M3ND Ltd | Information & communication | 2025 |
| Mabledon Development Limited | Real estate | 2008 |
| Mabledon Services Limited | Construction | 1986 |
| Maccounts Solutions Limited | Professional & scientific | 2013 |
| Macgregor & Associates Limited | Professional & scientific | 1998 |
| Macian Ltd | Professional & scientific | 2020 |
| Mack IT Consulting Ltd | Information & communication | 2022 |
| Mackie Avenue Resident Management Company Limited | Households | 2008 |
| Macro View Ltd | Information & communication | 2024 |
| Macrodata Refinement Ltd | Information & communication | 2022 |
| Macventure Consulting Limited | Professional & scientific | 2017 |
| Maddisons Residential Limited | Real estate | 2013 |
| Made 2 Measure Fenders LLP | | 2006 |
| Made Happy Gifts Limited | Wholesale & retail | 2020 |
| Made Studio Limited | Professional & scientific | 2008 |
| Madeira Park Property Company Limited | Households | 1989 |
| Madshall Properties Ltd | Real estate | 2023 |
| Madumbe Ltd | Professional & scientific | 2007 |
| Maeassist Ltd | Administrative & support | 2025 |
| Maffei Home of Havana Ltd | Wholesale & retail | 2018 |
| Magenta Digital Systems Limited | Information & communication | 2011 |
| Magheit Limited | Hospitality | 2020 |
| Magna Sigma Ltd | Information & communication | 2023 |
| Magnifiqueline. Ltd | Health & social care | 2024 |
| Magnify Design and Research Ltd | Information & communication | 2022 |
| Magnolia Home D&M Ltd | Construction | 2018 |
| Magrathea (UK) Limited | Professional & scientific | 2006 |
| Mahan Takeaway (Bexley) Limited | Hospitality | 2015 |
| Maharg Properties Limited | Construction | 1960 |
| Mahoni Artisan Furniture Ltd | Wholesale & retail | 2026 |
| Maia's Property Maintenance Company Ltd | Construction | 2025 |
| Maifayre Developments Limited | Other services | 1987 |
| Mailow Limited | Professional & scientific | 2026 |
| Mainspring Marketing LLP | | 2009 |
| Mainvalley Limited | Professional & scientific | 1984 |
| Majestic Cedar Cleaning Ltd | Administrative & support | 2025 |
| Majestic Cedar Ltd | Health & social care | 2023 |
| Majestic Cedar Properties Ltd | Real estate | 2024 |
| MAK Invest LLP | | 2017 |
| Make I.T. Count Limited | Information & communication | 2002 |
| Make Software Ltd | Information & communication | 2006 |
| Make US Care Group Ltd | Professional & scientific | 2021 |
| Make Your Mark Limited | Extraterritorial | 2008 |
| Making Digital Simple Limited | Administrative & support | 2011 |
| Making Scents Dog Training Limited | Education | 2022 |
| Making Waves Publishing Ltd | Information & communication | 2024 |
| Makkan Properties Ltd | Real estate | 2024 |
| Mako Associates Limited | Professional & scientific | 2026 |
| Maks Holdings Limited | Financial services | 2018 |
| Malaphor Ltd | Professional & scientific | 2026 |
| Malcolm R Smith Ltd | Transport & logistics | 2018 |
| Malford Patricia Ltd | Real estate | 2019 |
| Malic UK Limited | Wholesale & retail | 2000 |
| Malkoha Limited | Financial services | 2019 |
| Malla Studio Ltd | Information & communication | 2022 |
| Mallory Whitfield Consultants Limited | Professional & scientific | 2019 |
| Mallts Group Ltd | Construction | 2026 |
| Maltclaim Limited | Financial services | 1996 |
| Maltnott Investments Limited | Households | 2018 |
| Malton Way Green Spaces Ltd | Households | 2016 |
| Mama Makes Books Ltd | Information & communication | 2019 |
| Mamba Labels Limited | Manufacturing | 2006 |
| Mamoda LLP | | 2011 |
| Management Skills Centre Limited | Administrative & support | 2008 |
| Manchester Investors Limited | Real estate | 2023 |
| Mandi Limited | Administrative & support | 2014 |
| Mandli Cars Limited | Transport & logistics | 2018 |
| Mangrove Studios Ltd | Information & communication | 2017 |
| Manic Ceramix Ltd | Wholesale & retail | 2021 |
| Manifest Designs Ltd | Professional & scientific | 2022 |
| Manor Construction (Tunbridge Wells) Limited | Construction | 2017 |
| Manor Park (Tunbridge Wells) Residents Association Ltd | Households | 2021 |
| Manor Poultry Farm Limited | Real estate | 1957 |
| Manors Estates Ltd | Real estate | 2025 |
| Manorside Frant Limited | Health & social care | 2009 |
| Mansey Media Limited | Information & communication | 2023 |
| Mantra Ltd | Professional & scientific | 2021 |
| MAP Energy Funding Solutions Limited | Professional & scientific | 2012 |
| Mapflow Marketing Ltd | Professional & scientific | 2026 |
| Mapigrate Limited | Information & communication | 2013 |