| Mtpas LLP | | 2025 |
| MTQ Investments Ltd | Real estate | 2023 |
| MTS Fuels Ltd | Wholesale & retail | 2023 |
| MTS Management Services Limited | Administrative & support | 2004 |
| MTZ Medical Limited | Health & social care | 2018 |
| Muay Limited | Education | 2024 |
| Mubarak ALI Limited | Health & social care | 2018 |
| Mudfinishes Ltd | Construction | 2018 |
| Muditaa Limited | Wholesale & retail | 2025 |
| Mudiwarhys Ltd | Health & social care | 2018 |
| Mudy UK Limited | Hospitality | 2024 |
| Mueni Care Services Limited | Health & social care | 2016 |
| Muffin Consultancy Group Limited | Professional & scientific | 2024 |
| Mugano Capital Limited | Information & communication | 2022 |
| Mugen Euro Co., Limited | Manufacturing | 2006 |
| Muhammad Furqan Ehsan Ltd | Wholesale & retail | 2024 |
| Muhammed ALI Contracting Ltd | Other services | 2019 |
| Muinstallations Ltd | Construction | 2024 |
| Mujacicibric Limited | Professional & scientific | 2011 |
| Mujie Limited | Construction | 2026 |
| Mukaasemk Ltd | Hospitality | 2023 |
| Mukitia Trust | Health & social care | 2023 |
| Mukula Educare Recruitment Services Ltd | Administrative & support | 2025 |
| Mukuno Limited | Health & social care | 2023 |
| Mulberry Management Company (New Barnet) Limited(The) | Households | 1985 |
| Mulberry Property Services Limited | Real estate | 2023 |
| Mulevicius Building Services Limited | Construction | 2024 |
| Mullings Services Ltd | Real estate | 2021 |
| Multi Eyewear Limited | Manufacturing | 2025 |
| Multi Task Masters Limited | Real estate | 2019 |
| Multi-Mcmanus Ltd | Construction | 2025 |
| Multi-Sports Court Limited | Construction | 2006 |
| Multibug Limited | Administrative & support | 2003 |
| Multidimensional Space Printing Limited | Manufacturing | 2023 |
| Multination Records Ltd | Information & communication | 2024 |
| Multiplelisting Limited | Extraterritorial | 1991 |
| Multirole Contracts Ltd | Construction | 2014 |
| Multisport Distribution Limited | Wholesale & retail | 2009 |
| Multitruck Investments Limited | Real estate | 2013 |
| Multiverse Capital Limited | Administrative & support | 2005 |
| Multiverse Consulting Limited | Information & communication | 2012 |
| Mummu Ltd | Information & communication | 2010 |
| Mummys Bubble Ltd | Wholesale & retail | 2020 |
| Munakay Limited | Health & social care | 2014 |
| Munashe Care Consultacy Ltd | Health & social care | 2015 |
| Munch and Mula Ltd | Hospitality | 2026 |
| Munch on Wheels Ltd | Hospitality | 2025 |
| Munde Punjab DE Ltd | Administrative & support | 2019 |
| Municipal Cleansing Services (Holdings) Limited | Professional & scientific | 1990 |
| Municipal Cleansing Services Limited | Real estate | 1987 |
| Munirka DRY Fruit & Spice Merchants Ltd | Manufacturing | 2026 |
| Munissamy Ltd | Information & communication | 2011 |
| Murala Carpenters Ltd | Construction | 2022 |
| Murata Power Solutions (Milton Keynes) Limited | Manufacturing | 1982 |
| Murati Brickwork Ltd | Construction | 2023 |
| Murdoch International Limited | Wholesale & retail | 2020 |
| Mursi Mart Ltd | Wholesale & retail | 2025 |
| Mursley Farm Services Limited | Households | 2025 |
| Musa T Rashid Limited | Health & social care | 2023 |
| Musal Nigeria Limited | Real estate | 2022 |
| Musclemind Limited | Other services | 2025 |
| Musclesquad Limited | Other services | 2017 |
| Muse Radar Ltd | Information & communication | 2025 |
| Musebox Ltd | Information & communication | 2020 |
| Musengezi and Co LLP | | 2007 |
| Mushtaq and Sons Limited | Wholesale & retail | 2012 |
| Music Catalogue Purchases Limited | Arts & recreation | 2026 |
| Musical Gardens Limited | Professional & scientific | 2014 |
| Muslim Inspire Limited | Extraterritorial | 2015 |
| Muslims in Rail C.I.C. | Professional & scientific | 2019 |
| Muso - WE Hear YOU Limited | Information & communication | 2022 |
| Mussa Management Ltd | Wholesale & retail | 2026 |
| Mustaqim Ltd | Information & communication | 2005 |
| Mustard Lettings Limited | Real estate | 2013 |
| Mustard Models Limited | Professional & scientific | 2006 |
| Musztyfaga Design Ltd | Wholesale & retail | 2018 |
| Mutah Acha Ltd | Other services | 2026 |
| Mutapa Empire Ltd | Real estate | 2025 |
| Muthiga Limited | Manufacturing | 2014 |
| Mutimer International Ltd | Information & communication | 2023 |
| Mutmun & Co Holdings Ltd | Financial services | 2024 |
| Mutual Benefit Limited | Extraterritorial | 2002 |
| Muvvala Solutions and Services Ltd | Construction | 2016 |
| Muze Construction & Consultancy Ltd | Construction | 2019 |
| MV Technologies Limited | Information & communication | 2023 |
| Mvcp Limited | Professional & scientific | 2023 |
| MVI Corporate Merchandise Limited | Administrative & support | 1999 |
| Mvictoria Cleaning Ltd | Administrative & support | 2023 |
| Mviram Limited | Professional & scientific | 2016 |
| MVM Investments Ltd | Real estate | 2022 |
| MVP Financial Group Ltd | Financial services | 2025 |
| MVP Pro UK Limited | Energy | 2015 |
| Mvps Solutions Limited | Information & communication | 2022 |
| MVR IT Limited | Information & communication | 2014 |
| MVR Orthopedics Limited | Health & social care | 2022 |
| MVT Holding Ltd | Financial services | 2020 |
| MVY Engineering Ltd | Professional & scientific | 2024 |
| MW Accounting Services Limited | Professional & scientific | 2009 |
| MW Logistics Services Ltd | Construction | 2026 |
| MW World Limited | Financial services | 2026 |