| Mithal Propertise Ltd | Real estate | 2024 |
| Mittal Consultancy PVT Ltd | Information & communication | 2012 |
| Mittz Properties Ltd | Real estate | 2021 |
| Mivita Limited | Construction | 2017 |
| Mjcj Limited | Financial services | 2020 |
| Mjolie Co Ltd | Real estate | 2019 |
| Mk-And-Co Ltd | Professional & scientific | 2013 |
| MLW Accountancy Limited | Professional & scientific | 2019 |
| MMW Holdings Limited | Manufacturing | 2010 |
| MMW Holdings Properties Limited | Real estate | 2021 |
| MNP Limited | Administrative & support | 2005 |
| MNS Traders PVT Ltd | Wholesale & retail | 2022 |
| Mntn Trading Limited | Other services | 2026 |
| Mntrad Ltd | Transport & logistics | 2019 |
| Mobile & Vape Planet Ltd | Wholesale & retail | 2022 |
| Mobile App Mart Ltd | Information & communication | 2013 |
| Modern Property Investments Ltd | Real estate | 2011 |
| MODULUS2 Limited | Information & communication | 2012 |
| MOE & Associates Ltd | Wholesale & retail | 2018 |
| Momentous Relocation Limited | Transport & logistics | 1978 |
| Monaco Assets Ltd | Financial services | 2017 |
| Monaco Interiors Ltd | Professional & scientific | 2015 |
| Monaco Property Ltd | Professional & scientific | 2017 |
| Monk Travel Services Limited | Administrative & support | 2022 |
| Monoid Consulting Ltd | Information & communication | 2019 |
| Monreale Limited | Manufacturing | 2016 |
| Montague Properties UK Limited | Real estate | 2007 |
| Moon Phase Marketing Limited | Professional & scientific | 2021 |
| Moonshine & Sun Media Limited | Administrative & support | 2012 |
| Moore & Co. Consultants Ltd | Professional & scientific | 2018 |
| Morelli Limited | Manufacturing | 1996 |
| Moreton Media Ltd | Information & communication | 2021 |
| Mortgage Shop London Limited | Financial services | 2008 |
| MOS Skincare Ltd | Professional & scientific | 2024 |
| Mossa Wellness Co Limited | Manufacturing | 2025 |
| Mount Grace School | Education | 2011 |
| Move on Branding Limited | Manufacturing | 2014 |
| Moveupnow Ltd | Wholesale & retail | 2021 |
| Movilla Property Limited | Real estate | 2020 |
| Moya Jewellery Ltd | Manufacturing | 2019 |
| MP London Builders Ltd | Construction | 2016 |
| MPT Advisory Ltd | Professional & scientific | 2021 |
| MR and MRS Music Limited | Arts & recreation | 1969 |
| MR Ibrahim LLP | | 2024 |
| MR Keith Limited | Administrative & support | 2003 |
| MRC Partners Ltd | Information & communication | 2021 |
| Mrgavins Ltd | Wholesale & retail | 2024 |
| MRH Contracts Limited | Real estate | 2019 |
| MS Altun Property Limited | Health & social care | 2025 |
| Msbd Properties Ltd | Real estate | 2015 |
| MSW Rail Consulting Limited | Transport & logistics | 2014 |
| MTA Holdings Limited | Administrative & support | 2023 |
| MTD Accounting Services Ltd | Professional & scientific | 2025 |
| Mtheo Ltd | Households | 2022 |
| MTL Apartments Ltd | Hospitality | 2024 |
| Muhammad Tariq&Sons Ltd | Hospitality | 2024 |
| MUK London Limited | Administrative & support | 2026 |
| Mullan Construction Limited | Construction | 1984 |
| Multi Computer Services Ltd | Information & communication | 2020 |
| Multifoil Limited | Manufacturing | 1974 |
| Multitel Limited | Professional & scientific | 2011 |
| Mungun Ltd | Wholesale & retail | 2023 |
| Munro Brice & Co. Limited | Manufacturing | 1991 |
| Murrow Estate Ltd | Real estate | 2020 |
| Muse Cotswold Ltd | Hospitality | 2025 |
| Musera Marketing Limited | Professional & scientific | 2025 |
| Muuga Properties Limited | Real estate | 2024 |
| MV Surveyors Limited | Administrative & support | 2019 |
| Mwbmpb Limited | Real estate | 2020 |
| Mwcr Consultancy Ltd | Professional & scientific | 2025 |
| MXL Limited | Administrative & support | 2006 |
| My APS (London) Limited | Administrative & support | 2018 |
| My Muki Limited | Hospitality | 2022 |
| My Padel Club Ltd | Arts & recreation | 2025 |
| My Property Pros - the Exterior Cleaning Experts Ltd | Administrative & support | 2024 |
| My Property Pros Commercial Ltd | Administrative & support | 2021 |
| My Property Pros Ltd | Professional & scientific | 2024 |
| My Window Cleaner Franchising Limited | Administrative & support | 2014 |
| My Window Cleaner Limited | Households | 2005 |
| MYBESTIEM8 Ltd | Information & communication | 2023 |
| Mycare PAL Limited | Health & social care | 2021 |
| Mycleanteam Ltd | Administrative & support | 2024 |
| Mylan Pharma UK Limited | Professional & scientific | 2011 |
| Mysasi Ltd | Wholesale & retail | 2025 |
| Mysons Manufacturing Ltd | Manufacturing | 2018 |
| N & S Technologies Ltd | Information & communication | 2024 |
| N E D Electrical Ltd | Construction | 2025 |
| N S Accounting and Finance Limited | Professional & scientific | 2023 |
| N&K Associate Ltd | Professional & scientific | 2021 |
| N.R Tech Limited | Information & communication | 2018 |
| Nabaham Ltd | Administrative & support | 2017 |
| Nabucco Services Ltd | Administrative & support | 2018 |
| Naderi Cafe Ltd | Wholesale & retail | 2017 |
| Nadr Holdings Ltd | Administrative & support | 2026 |
| Nafisa Cakes Ltd | Manufacturing | 2025 |
| Naheed Khan Neurology Limited | Health & social care | 2026 |
| Namara Consulting Limited | Professional & scientific | 2010 |
| Namatelo Ltd | Information & communication | 2017 |
| Namo & Sons Solutions Limited | Information & communication | 2015 |
| Nanomobile Limited | Professional & scientific | 2009 |