| Misslebrook & Short Ltd | Construction | 2018 |
| Miteam Ltd | Information & communication | 2006 |
| Mitigation International Ltd | Professional & scientific | 2022 |
| MIX Messiah Productions Limited | Information & communication | 2020 |
| Mixcem Limited | Administrative & support | 2007 |
| MJ Rail Operations Limited | Construction | 2014 |
| MJG Holdings (Kent) Limited | Real estate | 2018 |
| Mjhtrades Ltd | Administrative & support | 2018 |
| MJT Communicating Limited | Health & social care | 2023 |
| MJT Gardening Ltd | Administrative & support | 2026 |
| MK Digital Studio Limited | Professional & scientific | 2025 |
| MK1 CAD Services Limited | Professional & scientific | 2018 |
| MKD Structures Ltd | Professional & scientific | 2026 |
| MLL (Kent) Ltd | Administrative & support | 2025 |
| MLS Consult Ltd | Other services | 2020 |
| MLS Enterprises Ltd. | Professional & scientific | 2023 |
| Mlsb Limited | Other services | 2018 |
| Mmchangebusiness Ltd | Professional & scientific | 2024 |
| Mmee Properties Ltd | Real estate | 2025 |
| Mmlr Investments Company Limited | Financial services | 2021 |
| MMT Centre Investment Limited | Real estate | 2011 |
| MO PR Advisory Limited | Professional & scientific | 2020 |
| Mobility for YOU Limited | Wholesale & retail | 2014 |
| Mobility Giant Ltd | Wholesale & retail | 2011 |
| Moco Interiors Ltd | Construction | 2018 |
| MOD Direct Marketing Ltd | Professional & scientific | 2020 |
| Model & Method Ltd | Information & communication | 2026 |
| Mojo Brand and Marketing Services Ltd | Professional & scientific | 2009 |
| Mojoandyallah Limited | Other services | 2025 |
| Mollie Properties Limited | Real estate | 2020 |
| Molly Watson Ltd | Professional & scientific | 2024 |
| Molyneux Place Limited | Households | 2003 |
| Momentum Financial Services Ltd | Financial services | 2019 |
| Monarch Associates (Matopos) Ltd | Administrative & support | 2017 |
| Monarch Foods International Limited | Wholesale & retail | 1991 |
| Monds Court Limited | Hospitality | 2005 |
| Monfardini Limited | Real estate | 2024 |
| Monique Montessori Nursery Ltd | Education | 2023 |
| Montague Global Ltd | Information & communication | 2023 |
| Montalto Ltd | Real estate | 2021 |
| Montholme Limited | Construction | 2011 |
| Montpelier London Ltd | Construction | 2024 |
| Montpellier Lets Ltd | Real estate | 2025 |
| Montreal Road Residents Association Limited | Real estate | 1965 |
| Moogees Ltd | Real estate | 2018 |
| Moon & Sons Ltd | Real estate | 2025 |
| Moonstone Vehicles and Weddings Ltd | Administrative & support | 2025 |
| Moore Professional Limited | Professional & scientific | 2013 |
| Moorshead Actuarial Limited | Professional & scientific | 2023 |
| Mooser Liesl UK Ltd | Wholesale & retail | 2025 |
| Moray Solutions Limited | Information & communication | 2010 |
| Morcom Technology Limited | Manufacturing | 2020 |
| More Italy Ltd | Hospitality | 2013 |
| More Than Golf Ltd | Administrative & support | 2017 |
| Morehampton Resourcing Ltd | Professional & scientific | 2025 |
| Morewood Close (Sevenoaks) Management Company Limited | Households | 2013 |
| Morfose Kent Ltd | Other services | 2026 |
| Morrie Digital Marketing Ltd | Administrative & support | 2026 |
| Mortgage Essentials (UK) Ltd | Financial services | 2008 |
| Mortimer Construction & Scaffolding Ltd | Construction | 2012 |
| Mosaic Engineering Limited | Administrative & support | 1993 |
| Mossford Construction Company Essex Limited | Construction | 1979 |
| Motopro Media Limited | Professional & scientific | 2022 |
| Motosys Limited | Information & communication | 2004 |
| Mount Davis Limited | Wholesale & retail | 2019 |
| Mount Vineyard (Bar & Restaurant) Limited | Hospitality | 2017 |
| Mountain Goats Ltd | Administrative & support | 2009 |
| Mousetrap (Kent) Limited | Wholesale & retail | 2002 |
| Moveover Makeover Limited | Other services | 2009 |
| Moving Spirit Limited | Information & communication | 2018 |
| MP Chauffeur Travel Ltd | Transport & logistics | 2025 |
| MPG Property Ltd | Real estate | 2024 |
| MPH Construction & Haulage Limited | Construction | 2014 |
| MPR Gold Haulage Ltd | Transport & logistics | 2019 |
| MR Bouncy Castle Ltd | Arts & recreation | 2010 |
| MR Chandrakant Dahya Manga Limited | Extraterritorial | 2025 |
| MR Prempy's Limited | Manufacturing | 2013 |
| MR. WHO Fashion Ltd | Wholesale & retail | 2024 |
| Mrcw Property Limited | Households | 2024 |
| Mrcyeo Limited | Administrative & support | 2006 |
| Mrfh Tate Ltd | Real estate | 2017 |
| MRL Strategic Consultancy Limited | Professional & scientific | 2023 |
| Mrsgolduk Ltd | Wholesale & retail | 2026 |
| MS Architecture & Design Consulting Limited | Professional & scientific | 2023 |
| MS Gillian Button Ltd | Extraterritorial | 2025 |
| MS Supply Chain Solutions Ltd | Professional & scientific | 2023 |
| MSB Elite Limited | Financial services | 2025 |
| MSB Pharma Consultancy Limited | Professional & scientific | 2026 |
| MSC Car Storage Limited | Transport & logistics | 2021 |
| MSG Office Holdings Limited | Financial services | 2021 |
| Msourcing Ltd | Administrative & support | 2025 |
| MSR Scaffolding Limited | Construction | 2017 |
| Muddy RUG Cleaning Ltd | Administrative & support | 2018 |
| Mulberry Consulting Services Limited | Professional & scientific | 2026 |
| Mulliner Chiropractic Limited | Health & social care | 2012 |
| Mumbai Central Kitchen Ltd | Hospitality | 2018 |
| Music and Stuff Limited | Wholesale & retail | 2020 |
| Mvdc Racing Ltd | Arts & recreation | 2021 |
| MVK Orthopaedics Ltd | Health & social care | 2014 |
| MW E-Commerce Ltd | Wholesale & retail | 2024 |