| Mcnamara-Yorke Limited | Construction | 2025 |
| Mcrs Industrial Roofing and Cladding Limited | Construction | 2021 |
| Mcstay Consultants Limited | Construction | 2022 |
| MD Ideas Ltd | Professional & scientific | 2018 |
| MD Import & Export Limited | Wholesale & retail | 2018 |
| MDE Medical Device Engineering and Supply Limited | Wholesale & retail | 2006 |
| ME Plus U Limited | Manufacturing | 2023 |
| Me&Sp Creative Ltd | Professional & scientific | 2015 |
| Mead Projects Limited | Professional & scientific | 2022 |
| Meadow Hill Consulting Ltd | Information & communication | 2020 |
| Meadows Mobile Farm Ltd | Administrative & support | 2026 |
| Meat and Seabass Limited | Financial services | 2020 |
| Mechanical & Electrical Services (Special Projects) Limited | Construction | 2005 |
| Medea Productions Ltd | Information & communication | 2024 |
| Medestan Limited | Construction | 2020 |
| Medi Source Solutions Limited | Administrative & support | 2023 |
| Medi-Protex Limited | Wholesale & retail | 2020 |
| Media by Design Limited | Extraterritorial | 1995 |
| Media Gardens Limited | Real estate | 2017 |
| Media Group Sussex Limited | Financial services | 2012 |
| Media Kettle Ltd | Information & communication | 2013 |
| Media Sages Limited | Professional & scientific | 2009 |
| Media Vessel Limited | Financial services | 2024 |
| Mediation Consultants Ltd | Professional & scientific | 2021 |
| Medical Industry EOT Ltd | Financial services | 2024 |
| Medical Industry Ltd | Administrative & support | 2017 |
| Medical Talent Limited | Administrative & support | 2009 |
| Medicalm Recruitment Limited | Administrative & support | 2022 |
| Medway Dental Care Limited | Health & social care | 2006 |
| Medway House Owners Limited | Households | 2024 |
| Meister Technology Limited | Information & communication | 2019 |
| Melania Service Limited | Health & social care | 2018 |
| Meliant Advisory Partners Limited | Professional & scientific | 2021 |
| Meloline Properties Limited | Real estate | 1987 |
| Melrose House Residents Company Limited | Households | 2003 |
| Menelik Ltd | Information & communication | 2011 |
| Mentech Ltd | Wholesale & retail | 2020 |
| Merafield Coaching & Consulting Ltd | Professional & scientific | 2024 |
| Mercedes-Benz Owners Ltd | Information & communication | 2018 |
| Merchant Otter Ltd | Professional & scientific | 2016 |
| Mercheroes Ltd | Wholesale & retail | 2026 |
| Mercoli Solutions Ltd | Information & communication | 2015 |
| Mereworth Motors Limited | Wholesale & retail | 2003 |
| Meridean Consulting Limited | Administrative & support | 2014 |
| Meridians (East Grinstead) Limited | Real estate | 2007 |
| Merkava Holdings Ltd. | Administrative & support | 2021 |
| Merkava Limited | Financial services | 2008 |
| Merkava Partners LLP | | 2008 |
| Merkland Limited | Administrative & support | 2024 |
| Merlin Technical Services Limited | Arts & recreation | 1973 |
| Mervellion Limited | Real estate | 2020 |
| MES Special Projects Limited | Extraterritorial | 2008 |
| Messing Around Limited | Health & social care | 2024 |
| Mestizo Ship Management Limited | Transport & logistics | 2024 |
| Metafrazein Limited | Other services | 2014 |
| Metanoia Coaching- Consultancy Ltd | Education | 2011 |
| Metatech Holdings Ltd | Financial services | 2022 |
| Meteo Process Ltd | Professional & scientific | 2023 |
| Meteronic Limited | Administrative & support | 1970 |
| Method Films Limited | Information & communication | 2015 |
| Method Fit Limited | Arts & recreation | 2018 |
| Metsaf Ltd | Professional & scientific | 2011 |
| Meyer & Family Limited | Professional & scientific | 2025 |
| MF Communications (TW) Limited | Information & communication | 2011 |
| MF Communications (UK) LLP | | 2008 |
| MF Communications Limited | Wholesale & retail | 2000 |
| Mfa/Como Drills Limited | Manufacturing | 2005 |
| MFB Legal Consultancy Limited | Professional & scientific | 2019 |
| MFL Encore Ltd | Education | 2025 |
| MFZ International Limited | Wholesale & retail | 2020 |
| MGH Cleaning Limited | Administrative & support | 2025 |
| MGP Design Limited | Professional & scientific | 2012 |
| Mgrow Ltd | Other services | 2014 |
| Mgstafford Ltd | Wholesale & retail | 2015 |
| MHB Roofing & Cladding Specialists Ltd | Construction | 2017 |
| MHD Collaborations Ltd | Professional & scientific | 2019 |
| MHD Collective Limited | Financial services | 2023 |
| MHP Building Contractors Ltd | Construction | 2017 |
| MI Boon Ltd | Health & social care | 2021 |
| Micasa Supported Ltd | Health & social care | 2022 |
| Michael Bull and Associates Ltd | Professional & scientific | 2021 |
| Michaelchurch Farming Limited | Agriculture & fishing | 1998 |
| Michel Property Holdings Ltd | Real estate | 2016 |
| Mickallen Consulting Limited | Information & communication | 2018 |
| MID Kent Developments Limited | Professional & scientific | 2012 |
| MID Kent Homes Limited | Construction | 1998 |
| MID Medical Services Limited | Health & social care | 2019 |
| Midicy Oast Bodiam Ltd | Financial services | 2022 |
| Mighty View Group LLP | | 2019 |
| Mike Moss Limited | Households | 2010 |
| Mike Moss Property LLP | | 2010 |
| Mike Prime Ltd | Arts & recreation | 2025 |
| Mile FLY Limited | Information & communication | 2024 |
| Miles From Home Ltd. | Professional & scientific | 2017 |
| Mill Court Residents Company Limited | Professional & scientific | 2006 |
| Mill Meats Limited | Wholesale & retail | 2013 |
| Millbrook Industrial Estate Site C Limited | Real estate | 2009 |
| Millbrook Site B Limited | Real estate | 2009 |
| Millbrook Site D Limited | Real estate | 2009 |
| Miller Farm Machinery Limited | Administrative & support | 2013 |