| Mstaaryan Ltd | Real estate | 2024 |
| MSW Food Ltd | Hospitality | 2017 |
| MT Advisory Ltd | Administrative & support | 2020 |
| MT Ashfaq Ltd | Transport & logistics | 2025 |
| MT Building Services SW Ltd | Construction | 2022 |
| MT Lettings Limited | Real estate | 2021 |
| MT Mastics Ltd | Construction | 2016 |
| MT78 Ltd | Transport & logistics | 2018 |
| MTA Chauffeur Ltd | Transport & logistics | 2023 |
| Mtank Ltd | Information & communication | 2019 |
| Mtaproductions Ltd | Information & communication | 2020 |
| MTB Plumbing & Heating Limited | Construction | 2020 |
| MTB Track Therapy Ltd | Arts & recreation | 2020 |
| MTC Electrical Solutions Ltd | Construction | 2025 |
| MTC Lets Limited | Real estate | 2023 |
| Mtdfish Ltd | Professional & scientific | 2024 |
| Mteez Health Care Ltd | Health & social care | 2022 |
| MTH Bidco Limited | Professional & scientific | 2016 |
| MTH Developments Ltd | Real estate | 2018 |
| MTH Midco 2 Limited | Professional & scientific | 2016 |
| MTH SPV 1 Ltd | Real estate | 2025 |
| Mthistle Ltd | Hospitality | 2026 |
| Mthuz Ltd | Health & social care | 2024 |
| MTI Services Ltd | Extraterritorial | 2024 |
| Mtla Consulting Ltd | Professional & scientific | 2024 |
| Mtla Ltd | Professional & scientific | 2018 |
| MTM Innovations Limited | Professional & scientific | 2012 |
| MTO Consultants Ltd | Professional & scientific | 2019 |
| MTS Corporation Ltd | Professional & scientific | 2022 |
| MTS Environmental Limited | Professional & scientific | 2005 |
| MTS Francis Court Solar Limited | Energy | 2013 |
| MTS Trefinnick Solar Ltd | Energy | 2012 |
| Mts-R Group Ltd | Other services | 2019 |
| MTU Property Ltd | Construction | 2025 |
| MTW Consulting Limited | Professional & scientific | 2021 |
| Mucha Construction Ltd | Manufacturing | 2017 |
| Muchall Cricket Coaching Limited | Arts & recreation | 2025 |
| Mucky Creature Ltd | Information & communication | 2014 |
| MUD and Bloom Limited | Wholesale & retail | 2017 |
| MUD and Mortar Limited | Construction | 2022 |
| MUD Dock Limited | Wholesale & retail | 1993 |
| MUD PIE Explorers C.I.C. | Education | 2014 |
| MUD SW Ltd | Construction | 2025 |
| Muddled Muse Ltd | Arts & recreation | 2025 |
| Muddy Feet Limited | Information & communication | 2007 |
| Muddy Meadow Ltd | Wholesale & retail | 2020 |
| Muddy Shoots Ltd | Other services | 2024 |
| Mudmuch Ltd. | Health & social care | 2018 |
| Mudstone Consulting Ltd | Professional & scientific | 2015 |
| Muelaner Engineering Ltd | Professional & scientific | 2018 |
| Muerabeta Smiles Limited | Health & social care | 2025 |
| Mufasa Supported Living Limited | Health & social care | 2026 |
| Muggoch Holdings Limited | Professional & scientific | 2013 |
| Mughal Balti Ltd | Hospitality | 2020 |
| Muhammad Hamza Ltd | Wholesale & retail | 2025 |
| Muhammad Shoukat Ltd | Wholesale & retail | 2023 |
| Muhammad Waheed Ltd | Wholesale & retail | 2025 |
| Muhammad Zain Ejaz Ltd | Wholesale & retail | 2025 |
| Muhecash Ltd | Wholesale & retail | 2015 |
| Muhemax Ltd | Wholesale & retail | 2021 |
| Muhestores Ltd | Wholesale & retail | 2019 |
| Muick Sandy Ltd | Wholesale & retail | 2023 |
| Muinin Legal Services Limited | Professional & scientific | 2022 |
| Muio.Org Ltd | Information & communication | 2010 |
| Muirlands Advisory Limited | Information & communication | 2023 |
| Muisa Cleaning Services Limited | Administrative & support | 2025 |
| Muisa Healthcare Limited | Administrative & support | 2014 |
| Muka Health Care Ltd | Health & social care | 2022 |
| Mula Lounge Ltd | Hospitality | 2018 |
| Mulberry Building Services Limited | Construction | 2005 |
| Mulberry Court (Brislington) Management Company Limited | Households | 2005 |
| Mulberry Developments (Thornbury) Limited | Construction | 2017 |
| Mulberry Events Advisors Ltd | Professional & scientific | 2025 |
| Mulberry Insurance Brokers Limited | Financial services | 2013 |
| Mulberry Mews (Silver Street) Management Company Limited | Households | 2005 |
| Mulberry Montessori House Nursery and Preschool Ltd | Education | 2024 |
| Mulberry Tuition Ltd | Education | 2024 |
| Mulbury Consultants Limited | Construction | 2013 |
| Mullacott Caravan and Marine Limited | Manufacturing | 1941 |
| Mullahimachines Ltd | Manufacturing | 2025 |
| Muller Automotive UK Limited | Wholesale & retail | 2024 |
| Muller House Residents Association Ltd | Households | 2026 |
| Mullin SLF Limited | Financial services | 2019 |
| Mullion Professional Services Ltd | Construction | 2013 |
| Mullis Family Furniture Ltd | Wholesale & retail | 2026 |
| Multi Coat Print Finishers Limited | Manufacturing | 2011 |
| Multi Property Ltd | Other services | 2015 |
| Multi Resin Specialist & Construction Ltd | Construction | 2026 |
| Multi-Crete Concrete and Concrete Pumping Ltd | Manufacturing | 2005 |
| Multicolors Marvel Stud Ltd | Other services | 2025 |
| Multicoms Home Ltd | Construction | 2020 |
| Multicoms Solutions (South-West) Limited | Administrative & support | 2008 |
| Multiform Roofing Ltd | Construction | 2012 |
| Multihyphen Ltd | Professional & scientific | 2021 |
| Multilingual Matters Limited | Education | 2013 |
| Multiplicit Ltd | Other services | 2020 |
| Multipower Engineering Limited | Manufacturing | 2022 |
| Multiray Ltd | Real estate | 2019 |
| Multisensations Ltd | Education | 2009 |
| Multiskills Technologies Ltd | Wholesale & retail | 2025 |