| MJW Surgical & Dental Instruments Ltd | Wholesale & retail | 2020 |
| MK Consulting - Tax & Accounts Ltd | Professional & scientific | 2026 |
| MK EAR WAX Clinic Ltd | Health & social care | 2023 |
| MK Livin Ltd | Real estate | 2024 |
| MK Planning Designs Limited | Professional & scientific | 2019 |
| MK Premium Properties Limited | Real estate | 2025 |
| MK Shine Ltd | Administrative & support | 2018 |
| MK Trading Solutions Limited | Wholesale & retail | 2024 |
| MK Trident Technologies Ltd | Information & communication | 2019 |
| MK Woman Health Ltd | Health & social care | 2024 |
| MK-2 Barber Limited | Other services | 2023 |
| MK1 Barbers Limited | Other services | 2019 |
| MKA Estates Ltd | Real estate | 2026 |
| MKB Cleaning Services Ltd | Administrative & support | 2021 |
| MKC Solutions Ltd | Administrative & support | 1998 |
| Mkcn Developments Limited | Real estate | 2019 |
| Mkmh Ltd | Transport & logistics | 2026 |
| MKP Electric Limited | Construction | 2017 |
| Mksc Ltd | Construction | 2021 |
| Mkvk Solutions Limited | Information & communication | 2022 |
| ML Estates London Ltd | Hospitality | 2026 |
| ML Leisure London Ltd | Hospitality | 2026 |
| ML Train Services Ltd | Wholesale & retail | 2025 |
| MLH Surveying Limited | Professional & scientific | 2011 |
| MLI Controls Ltd | Construction | 2015 |
| MLS Management Client Services Limited | Professional & scientific | 2016 |
| MLU Ventures Limited | Manufacturing | 2025 |
| MM AV Limited | Other services | 2024 |
| MM Bubs Ltd | Wholesale & retail | 2026 |
| MM Experts Ltd | Information & communication | 2012 |
| MM Heating & Boiler Installation Ltd | Construction | 2019 |
| MM Planning & Drawings Ltd | Professional & scientific | 2019 |
| MMA Collection Limited | Wholesale & retail | 2025 |
| MMB Consultants Limited | Financial services | 2015 |
| MMD Smart Ltd | Information & communication | 2020 |
| Mmienu II Ltd | Transport & logistics | 2026 |
| Mmirha Limited | Professional & scientific | 2026 |
| MML Trans Ltd | Transport & logistics | 2021 |
| Mmlt Holdings Limited | Financial services | 2026 |
| MMM FC Ltd | Hospitality | 2024 |
| MMM Fried Chicken (London) Ltd | Hospitality | 2019 |
| MMW Traders Ltd | Hospitality | 2024 |
| MNA Laboratory Ltd | Professional & scientific | 2019 |
| Mnazir Locum Ltd | Health & social care | 2023 |
| Mnge Limited | Other services | 2025 |
| Mngoods Ltd | Wholesale & retail | 2021 |
| MNM Ductwork Limited | Construction | 2012 |
| Mnoor&Co Ltd | Administrative & support | 2025 |
| MNP Estates Ltd | Real estate | 2025 |
| MNT Build Ltd | Construction | 2024 |
| Mnuk Service Limited | Wholesale & retail | 2019 |
| Mnya Properties Limited | Real estate | 2022 |
| Moalim Hassan Limited | Information & communication | 2022 |
| Mobicom IT Ltd | Information & communication | 2017 |
| Mobile & Bitz Ltd | Other services | 2015 |
| Mobile & Vape Sutton Limited | Wholesale & retail | 2025 |
| Mobile Auto Diagnostics and Locksmith Limited | Wholesale & retail | 2025 |
| Mobile Electronics Ltd | Manufacturing | 2024 |
| Mobile Tyres Service Ltd | Other services | 2024 |
| Mobile Xchange Ltd | Other services | 2017 |
| Mobilelink Croydon Ltd | Wholesale & retail | 2023 |
| Mobilesaunaservices Ltd | Health & social care | 2022 |
| Mobilink Croydon Ltd | Wholesale & retail | 2023 |
| Mobilink Services Croydon Limited | Wholesale & retail | 2026 |
| Mobility Chauffeurs Ltd | Transport & logistics | 2020 |
| Mobility Transport Ltd | Transport & logistics | 2012 |
| Mobitech Smart Ltd | Wholesale & retail | 2024 |
| Moca 10 Old Dover Road Ltd | Hospitality | 2026 |
| Moch Limited | Professional & scientific | 2022 |
| Model Care Services Ltd | Administrative & support | 2021 |
| Model Lettings Ltd | Real estate | 2024 |
| Models a Bureau Limited | Professional & scientific | 2021 |
| Models Advice Bureau Limited | Professional & scientific | 2016 |
| Modern Airconditioning Limited | Construction | 2013 |
| Modern Labelling Methods Holdings Limited | Financial services | 2018 |
| Modern Labelling Methods Limited | Manufacturing | 2005 |
| Modern Metal Windows Limited | Construction | 2010 |
| Modern Montessori International Limited | Education | 1997 |
| Modern Supply Co Ltd | Wholesale & retail | 2026 |
| Modernisers Ltd | Construction | 2019 |
| Modular Apparel IP Ltd | Administrative & support | 2020 |
| Modular Apparel Ltd | Wholesale & retail | 2020 |
| Modular Fine Art Limited | Wholesale & retail | 2018 |
| Moglad Care Ltd | Professional & scientific | 2018 |
| Mohammed Baki Ltd | Professional & scientific | 2024 |
| Mohammed Raja Lettings Ltd | Real estate | 2012 |
| Mohan Nanjappan UK Limited | Information & communication | 2020 |
| Mohan Rajendra Service Ltd | Construction | 2019 |
| Mohanraj Karunanithi UK Ltd | Construction | 2019 |
| Mojeek Limited | Information & communication | 2009 |
| Mojito Restaurant Ltd | Hospitality | 2023 |
| Mojo Bones Ltd | Information & communication | 2011 |
| Mojostack Properties Ltd | Real estate | 2026 |
| Mokkai Worktops Ltd | Wholesale & retail | 2022 |
| Mokon Limited | Health & social care | 2012 |
| Moksy Ltd | Information & communication | 2019 |
| Molak Limited | Health & social care | 2013 |
| Mole Place (Molesey) Residents Management Company Limited | Households | 2024 |
| Molfar Heritage Limited | Real estate | 2024 |
| Momentswithadanna Ltd | Wholesale & retail | 2025 |