| MSD Promotions Limited | Arts & recreation | 2006 |
| MSE Interiors Limited | Construction | 2015 |
| MSF Associates Limited | Professional & scientific | 2006 |
| MSF Capital Limited | Financial services | 2025 |
| MSG Pro Services Ltd | Administrative & support | 2024 |
| Msgh Limited | Extraterritorial | 2022 |
| MSJ Consulting Limited | Professional & scientific | 2025 |
| Msjc Consulting Ltd | Real estate | 2017 |
| MSK Technologies Limited | Information & communication | 2015 |
| MSK.7 Ltd | Transport & logistics | 2025 |
| Mskk Properties Limited | Real estate | 2023 |
| MSL Clinical Hypnotherapy Ltd | Other services | 2024 |
| MSM Healthcare Ltd | Administrative & support | 2014 |
| MSM Hexagon Ltd | Financial services | 2022 |
| MSM Independent Financial Services Limited | Financial services | 2001 |
| Msma Vape Ltd | Wholesale & retail | 2022 |
| Msml Limited | Administrative & support | 2002 |
| MSN Hire Limited | Administrative & support | 2017 |
| MSN Properties Limited | Real estate | 2014 |
| MSO Buy to LET Company Limited | Real estate | 2022 |
| MSP Consultancy Services Ltd | Other services | 2019 |
| MSP Contracts Ltd | Construction | 2024 |
| MSP1 Limited | Real estate | 2021 |
| Msquare Analytical Ltd | Manufacturing | 2023 |
| MSR Civils Limited | Construction | 2015 |
| MSR Formwork UK Limited | Construction | 2026 |
| MSR Immigration Services Limited | Professional & scientific | 2013 |
| MSR Project Services Limited | Other services | 2011 |
| Msrr 2 Holding Limited | Financial services | 2024 |
| Msrr 2 Limited | Financial services | 2015 |
| MSS Developments Limited | Construction | 1966 |
| MSS Motors Ltd | Wholesale & retail | 2018 |
| MSS Workshop Limited | Manufacturing | 2005 |
| MSS Yorkshire Ltd | Hospitality | 2024 |
| MSS Yorkshire Staff Ltd | Administrative & support | 2024 |
| Msssb Limited | Real estate | 2026 |
| Mstr Gringo Studio Ltd | Professional & scientific | 2026 |
| MSW York Limited | Manufacturing | 2012 |
| MSY Group Ltd | Wholesale & retail | 2025 |
| MT Auto Services (Leeds) Ltd | Wholesale & retail | 2026 |
| MT Cars Leeds Limited | Extraterritorial | 2001 |
| MT Catering Leeds Limited | Hospitality | 2023 |
| MT Construction Management Ltd | Extraterritorial | 2022 |
| MT Foods Leeds Limited | Hospitality | 2026 |
| MT Freight Solutions Ltd | Transport & logistics | 2020 |
| MT Mechanical Services Ltd | Administrative & support | 2014 |
| MT Motors (Gildersome) Limited | Wholesale & retail | 2014 |
| MT Pass Holdings Limited | Professional & scientific | 2002 |
| MT Property Services Yorkshire Ltd | Construction | 2023 |
| MT Repairs and Maintenance Ltd | Other services | 2024 |
| MT UK Properties Limited | Real estate | 2024 |
| MT. Ford Ltd | Information & communication | 2015 |
| MT1 Building Ltd | Health & social care | 2020 |
| MTA Piano Ltd | Wholesale & retail | 2025 |
| Mtaha Limited | Health & social care | 2023 |
| MTC Civils Ltd | Construction | 2023 |
| Mtcr Limited | Transport & logistics | 2023 |
| MTD Trade Ltd | Wholesale & retail | 2020 |
| MTE Heat Treatment Limited | Manufacturing | 2009 |
| Mtec Mechanical Engineering Ltd | Manufacturing | 2025 |
| Mtek Solutions Ltd | Manufacturing | 2025 |
| MTH Property Investments Ltd | Real estate | 2023 |
| MTI Restaurants Ltd | Hospitality | 2022 |
| MTJ Property Solutions Limited | Real estate | 2026 |
| Mtkcurier Ltd | Transport & logistics | 2025 |
| Mtlogistics Limited | Transport & logistics | 2023 |
| MTM Educational Consultancy Limited | Education | 2020 |
| MTM Enterprises Limited | Real estate | 2000 |
| MTM Machining UK Ltd | Manufacturing | 2010 |
| Mtpk Limited | Wholesale & retail | 2024 |
| MTR Group Holding Limited | Financial services | 2016 |
| Mtrp Ltd | Administrative & support | 2001 |
| MTS Systems Limited | Manufacturing | 1979 |
| MTT Consultancy Limited | Professional & scientific | 2023 |
| MTU Autos Ltd | Wholesale & retail | 2025 |
| MU VEE Limited | Health & social care | 2023 |
| Muaso Records Ltd | Information & communication | 2023 |
| Mubashars Locum Services Ltd | Health & social care | 2017 |
| Mubeen Fresh Foods Ltd | Wholesale & retail | 2026 |
| MUD & Iron Ltd | Arts & recreation | 2026 |
| Mudathir Bambi Ltd | Wholesale & retail | 2026 |
| Muddy Paws Ltd | Other services | 2025 |
| Mudra Leeds Ltd | Arts & recreation | 2026 |
| Muff-Downes Properties Ltd | Construction | 2024 |
| Mufg Corporate Governance Limited | Professional & scientific | 2004 |
| Mufg Corporate Markets (UK) Limited | Administrative & support | 1991 |
| Mufg Corporate Markets IR Limited | Information & communication | 2006 |
| Mufg Corporate Markets Treasury Limited | Administrative & support | 1991 |
| Mufg Corporate Markets Trustees (Nominees) Limited | Other services | 2000 |
| Mufg Corporate Markets Trustees (UK) Limited | Other services | 1992 |
| Mufg Pension & Market Services (UK) Limited | Financial services | 2013 |
| Mufg PMS Corporate Director Limited | Administrative & support | 2017 |
| Mufg PMS Corporate Secretary Limited | Administrative & support | 2017 |
| Mufg PMS Service Company Limited | Other services | 2019 |
| Mufg Share Plan Services Limited | Financial services | 2004 |
| Mugged OFF Enterprise Ltd | Wholesale & retail | 2025 |
| Mughal Tandoori Ltd | Hospitality | 2021 |
| Mughal-Buy Limited | Wholesale & retail | 2022 |
| Mughub Ltd | Health & social care | 2025 |
| Muhammad Afrasyab Tech Limited | Wholesale & retail | 2023 |