| MJS Management Solutions Limited | Professional & scientific | 2013 |
| MJW Construction South East Limited | Construction | 2013 |
| MK Autotrade Ltd | Wholesale & retail | 2025 |
| MK Builders (Medway) Ltd | Construction | 2007 |
| MK1SOUND Limited | Arts & recreation | 2008 |
| ML Accounting Services Limited | Professional & scientific | 2019 |
| ML Labour Link Ltd | Administrative & support | 2018 |
| MLA Property London Ltd | Real estate | 2025 |
| MLA Thermal Ltd | Construction | 2022 |
| MLK Building Services Ltd | Construction | 2016 |
| MLR Ship Services Limited | Wholesale & retail | 2016 |
| MLW Building Services Limited | Construction | 2014 |
| MM Osteopathy Limited | Health & social care | 2025 |
| MMB Construction Group Ltd | Manufacturing | 2026 |
| Mmlait Ltd | Information & communication | 2018 |
| MMO Project Management Limited | Construction | 2012 |
| Mmplacements Ltd | Professional & scientific | 2023 |
| MMT Global Trading & Solutions Limited | Wholesale & retail | 2026 |
| MO0DV Ltd | Financial services | 2025 |
| MO2 Production Ltd | Administrative & support | 2025 |
| MOA Logistics Limited | Transport & logistics | 2025 |
| Mobile Car Tinting Ltd | Wholesale & retail | 2012 |
| Mobile Music (Medway) Limited | Wholesale & retail | 2003 |
| Mobilevery Ltd | Wholesale & retail | 2020 |
| Mobilynx Foods Limited | Hospitality | 2020 |
| Mobipictures Limited | Information & communication | 2019 |
| MOD Build Limited | Construction | 2020 |
| Moda Fashions Limited | Wholesale & retail | 2016 |
| Modal Limited | Real estate | 2025 |
| Model Technology & Associates Limited | Administrative & support | 1998 |
| Modennycollections Limited | Health & social care | 2026 |
| Modern Day Medics C.I.C. | Education | 2019 |
| Modular Groundworks Limited | Construction | 1997 |
| MOG Investments | Professional & scientific | 2025 |
| Moglamour Services Ltd | Health & social care | 2024 |
| MOH Glam Ltd | Wholesale & retail | 2026 |
| Moksha FMC Limited | Professional & scientific | 2016 |
| Moldo-Aspect Ltd | Construction | 2026 |
| Molis Services Limited | Transport & logistics | 2011 |
| MOM Amplified Ltd | Other services | 2024 |
| Momentum Options Limited | Information & communication | 2010 |
| Monada Professional Services Ltd | Information & communication | 2025 |
| Monks Developments Limited | Construction | 2021 |
| Monocut Promotions Ltd | Administrative & support | 2025 |
| Monster Baits Ltd | Wholesale & retail | 2023 |
| Montana Moss Ltd | Real estate | 2025 |
| Monteiro-Jones Property Lettings Ltd | Real estate | 2019 |
| Montgomery Boilers Ltd | Construction | 2016 |
| Mood Studios Education Limited | Education | 2025 |
| Moon at Dawn Ltd | Professional & scientific | 2025 |
| Mooncox Ltd | Real estate | 2024 |
| Moore Heating & Plumbing Ltd | Construction | 2025 |
| Mopclean Cleaning Limited | Administrative & support | 2026 |
| Mora's Taste Ltd | Hospitality | 2024 |
| Morah Medical Services Limited | Health & social care | 2011 |
| Morgan Properties (Kent) Limited | Construction | 2005 |
| Morizon Ltd | Information & communication | 2021 |
| Morpheus Technologies Limited | Information & communication | 2008 |
| Morr Consults Ltd | Professional & scientific | 2017 |
| Morr Professionals Limited | Professional & scientific | 2014 |
| Morrison Advisers Ltd | Education | 2011 |
| Mortarside Limited | Real estate | 1979 |
| Mortgage Able Limited | Financial services | 2013 |
| Mortgage Advice Partner Ltd | Extraterritorial | 2018 |
| Mosharraf Limited | Health & social care | 2010 |
| Mosorov Group Limited | Wholesale & retail | 2024 |
| Moss Supported Services Ltd | Health & social care | 2023 |
| Mostat Company Ltd | Health & social care | 2013 |
| Mosym Consulting Ltd | Information & communication | 2020 |
| Mosym Healthcare Ltd | Health & social care | 2023 |
| Motiq Technologies Ltd | Information & communication | 2025 |
| Motor Trade Stock Suppliers Limited | Wholesale & retail | 2017 |
| Mountain Homes & Properties Ltd | Extraterritorial | 2022 |
| Move South Limited | Real estate | 2023 |
| Moyo Group Ltd | Financial services | 2022 |
| MPA Offshore Fibre Services Ltd | Professional & scientific | 2023 |
| Mpaz Properties Limited | Real estate | 2026 |
| Mpwg Limited | Administrative & support | 2017 |
| MR Growth Ltd | Professional & scientific | 2021 |
| MR Invoice Limited | Professional & scientific | 2020 |
| MR Lumpy & Friends Limited | Wholesale & retail | 2022 |
| MR P'S Classic Amusements Limited | Arts & recreation | 2012 |
| MR Plant and Machinery Sales (UK) Limited | Wholesale & retail | 2026 |
| MR Spud Loaded Potatoes Ltd | Wholesale & retail | 2025 |
| Mr.Dc Limited | Real estate | 2025 |
| Mrcm Ltd | Real estate | 2022 |
| MRD Pharma Consultancy Limited | Professional & scientific | 2018 |
| Mrfi Services Ltd | Transport & logistics | 2017 |
| MRM Security Strategies Limited | Professional & scientific | 2025 |
| Mrout Limited | Other services | 2017 |
| MRS Bakers Medway Theatre Company Ltd | Arts & recreation | 2019 |
| MRS Sourdough Bakery Ltd | Manufacturing | 2021 |
| MS Cooper & SON Ltd | Construction | 2022 |
| MS Deol Ltd | Wholesale & retail | 2016 |
| MS Motorsport Limited | Wholesale & retail | 2025 |
| MS Rigging Ltd | Professional & scientific | 2011 |
| MSD Project Ltd | Construction | 2015 |
| MSD Warehouse Limited | Wholesale & retail | 2012 |
| MSD Wholesale Limited | Wholesale & retail | 2012 |
| Msdc & SON Ltd | Administrative & support | 2014 |