| Material Insights Limited | Professional & scientific | 2023 |
| Material Markets Limited | Professional & scientific | 2025 |
| Mateusz Jurga Ltd | Information & communication | 2024 |
| Matfield Medical Limited | Health & social care | 2021 |
| Mathetheuo Consulting Services Ltd | Professional & scientific | 2024 |
| Maths in Motion Limited | Information & communication | 2017 |
| Matigf Ltd | Health & social care | 2018 |
| Matiéu Monde Limited | Wholesale & retail | 2021 |
| Matt Martin Nails Trade & Training Academy Ltd | Other services | 2019 |
| Matt Paterson Engineering Limited | Professional & scientific | 2017 |
| Mattey & Co Restaurants Ltd | Hospitality | 2024 |
| Matthews Cosmetics Ltd | Wholesale & retail | 2024 |
| Matthews' Aquatic Paradise Ltd | Agriculture & fishing | 2024 |
| Matza Enterprises Limited | Manufacturing | 2018 |
| Maufin International Services Ltd. | Information & communication | 2023 |
| Maulkerson Ltd | Construction | 2017 |
| Mauren Services Limited | Administrative & support | 2021 |
| Mauvseed Limited | Wholesale & retail | 2025 |
| Mauvseed Properties Ltd | Real estate | 2026 |
| Maveo Ltd | Wholesale & retail | 2025 |
| Maverick Flavour Consultancy Limited | Professional & scientific | 2024 |
| MAX Graphic Studio Ltd | Information & communication | 2026 |
| Maxfy Ltd | Wholesale & retail | 2025 |
| Maxia Limited | Wholesale & retail | 2007 |
| Maxima Opus Ltd | Information & communication | 2025 |
| Maximim UK Ltd | Professional & scientific | 2026 |
| Maxlink Tech Limited | Wholesale & retail | 2024 |
| Maxpower Limited | Construction | 2015 |
| Maxxexpert Ltd | Wholesale & retail | 2017 |
| MAY & CHI Investment Company Ltd | Real estate | 2020 |
| MAY Gardens Cricket Field Road Management Ltd | Professional & scientific | 2017 |
| Maya & Maani Ltd | Wholesale & retail | 2025 |
| Mayashailarani Limited | Health & social care | 2025 |
| Mayfair Bespoke Ltd. | Wholesale & retail | 2024 |
| Mayflower Property Limited | Real estate | 2025 |
| Maynard House Limited | Manufacturing | 2003 |
| Maynewater House Limited | Real estate | 2013 |
| Mayo Living Ltd | Real estate | 2024 |
| Mays Accounting Limited | Professional & scientific | 2003 |
| Mays and Berry Limited | Hospitality | 2021 |
| Mayston Limited | Manufacturing | 2025 |
| Mayura Estates Limited | Real estate | 2025 |
| Maze Birmingham Ltd | Manufacturing | 2026 |
| Mazemesh Ltd | Information & communication | 2026 |
| Mazuna Services Ltd | Transport & logistics | 2026 |
| MB Connect Ltd | Administrative & support | 2013 |
| MB Innovations Ltd | Professional & scientific | 2020 |
| MBN Properties Ltd | Real estate | 2011 |
| MBR Engineering Ltd | Construction | 2018 |
| MBX Limited | Information & communication | 2012 |
| MC Cardiology Ltd | Health & social care | 2023 |
| MC Managerial Services Limited | Administrative & support | 2018 |
| MC Mihai Construct Ltd | Construction | 2020 |
| MC08 Ltd | Professional & scientific | 2022 |
| Mcauleycurtis Limited | Real estate | 2019 |
| Mccarthy Lettings & Property Ltd | Real estate | 2025 |
| Mccorkindale Ltd | Professional & scientific | 2022 |
| Mcculloughs Holdings Limited | Financial services | 2019 |
| Mcel Limited | Information & communication | 2014 |
| Mcgill Digital Ltd | Wholesale & retail | 2021 |
| Mckc Media Ltd | Information & communication | 2024 |
| Mckenzie Limited | Administrative & support | 2005 |
| MCM Subsea Engineering (UK) Ltd | Professional & scientific | 2021 |
| MCR Strategic Ltd | Professional & scientific | 2017 |
| MCR Web Services Ltd | Information & communication | 2020 |
| MCT MK Ltd | Transport & logistics | 2025 |
| Mctl Global Limited | Manufacturing | 2024 |
| MD Collective Ltd | Professional & scientific | 2019 |
| MD Self Defense Condesa Ltd | Education | 2025 |
| Mdab Enterprise Ltd | Wholesale & retail | 2023 |
| Mdart Ltd | Wholesale & retail | 2024 |
| ME and My Friend Ltd | Health & social care | 2019 |
| ME Maintenance Limited | Construction | 2007 |
| Meadcroft Limited | Hospitality | 2021 |
| Meadow & Moorings Ltd | Hospitality | 2026 |
| Meadow Oak Group Limited | Financial services | 2026 |
| Mean Gaming Ltd | Wholesale & retail | 2024 |
| Meat & Greet BSE Ltd | Hospitality | 2019 |
| Mechd Ltd | Information & communication | 2026 |
| MED Link Expert Witness Ltd | Health & social care | 2025 |
| Medak Health Ltd | Health & social care | 2023 |
| Medallion NET Company Limited | Wholesale & retail | 1989 |
| Media City Properties Ltd | Real estate | 2009 |
| Media Edge Solution Ltd | Wholesale & retail | 2025 |
| Medianest Ltd | Information & communication | 2025 |
| Medianet Group Ltd | Information & communication | 2026 |
| Medibridge Enterprise Ltd | Health & social care | 2026 |
| Medical Department Services Ltd | Administrative & support | 2025 |
| Medicrecall Limited | Education | 2025 |
| Medimartia Ltd | Wholesale & retail | 2025 |
| Medisam Limited | Health & social care | 2019 |
| Medispa Skin Clinic Limited | Health & social care | 2025 |
| Meditact Consulting Limited | Professional & scientific | 2014 |
| Meditax Ltd | Professional & scientific | 2009 |
| Medix Supplies Ltd | Wholesale & retail | 2022 |
| Mednostalgia Limited | Administrative & support | 2025 |
| Medo Chippy Ltd | Hospitality | 2026 |
| Medpass Ltd | Public administration | 2025 |
| Medtech I2I Ltd | Information & communication | 2026 |
| Medusa Design Ltd | Professional & scientific | 2010 |