| Morgan Inverclyde Limited | Administrative & support | 1997 |
| Morgan Parkes Recruitment Limited | Administrative & support | 2014 |
| Morphix Limited | Information & communication | 2024 |
| Morris and Summerfield Limited | Real estate | 2020 |
| Morrow Pictures Ltd | Information & communication | 2026 |
| Mortgage Trust Limited | Financial services | 1986 |
| Mortgage Trust Services PLC | Financial services | 2000 |
| MORTGAGE360 Ltd | Financial services | 2018 |
| Morton Medical Services Limited | Health & social care | 2016 |
| MOS Joinery Limited | Construction | 2021 |
| Mosaique Limited | Information & communication | 2005 |
| Moseley Court Care Services Ltd | Health & social care | 2018 |
| Moseley Cricket Club Limited | Arts & recreation | 2018 |
| Moseley Cricket Club Trading Limited | Arts & recreation | 2018 |
| Moseley NO50 Ltd | Real estate | 2018 |
| Moses Kushner Limited | Wholesale & retail | 2021 |
| Moses Kushner London Limited | Financial services | 2022 |
| Moss Building Contractors Limited | Construction | 2004 |
| Mosskirk Ltd | Wholesale & retail | 2024 |
| Most Digital Limited | Professional & scientific | 2017 |
| Most Popular Limited | Wholesale & retail | 2018 |
| MOT Bods Ltd | Professional & scientific | 2025 |
| Moth Property Limited | Real estate | 2018 |
| Motion Communications Limited | Extraterritorial | 2012 |
| Motorclub Services Ltd | Wholesale & retail | 2024 |
| Motorfair Limited | Wholesale & retail | 2006 |
| Motorhomer Ltd | Information & communication | 2015 |
| Motorhomes Wanted (Brokerage) Limited | Wholesale & retail | 2022 |
| Motorserv UK Solihull Ltd | Wholesale & retail | 2024 |
| Motorworld UK Group Ltd | Wholesale & retail | 2022 |
| Mouchak Street Limited | Hospitality | 2025 |
| Moukey Limited | Administrative & support | 2007 |
| Mount Property and Rental Limited | Real estate | 2013 |
| Mountain Trading Limited | Wholesale & retail | 2021 |
| Mountain-Bike Instructors' Award Scheme Limited | Education | 2012 |
| Mouve Online Limited | Wholesale & retail | 2016 |
| Move IT Store IT Limited | Manufacturing | 2014 |
| Move With MEG Limited | Other services | 2023 |
| Movers Estate Agents Limited | Real estate | 2012 |
| Movida Property Management Ltd | Real estate | 2022 |
| MP Shelly Limited | Hospitality | 2025 |
| Mpac UK Limited | Other services | 2006 |
| Mpegears Ltd | Professional & scientific | 2020 |
| MPI Projects Ltd | Real estate | 2023 |
| MPK Project Consultancy Ltd | Professional & scientific | 2026 |
| MPK Project Management Ltd | Construction | 2021 |
| Mpower Social Housing Ltd | Hospitality | 2024 |
| MPP Homes Ltd | Real estate | 2019 |
| MPT Consulting Ltd | Professional & scientific | 2025 |
| MQ Financials Limited | Professional & scientific | 2012 |
| MQ Marketing Ltd | Other services | 2019 |
| MQP International Ltd | Professional & scientific | 2016 |
| MR & MRS Singh Business Ltd | Real estate | 2025 |
| MR Automotive Management Ltd | Administrative & support | 2015 |
| MR Benjamin Session and Editorial Ltd Ltd | Other services | 2026 |
| MR Bham Housing Ltd | Real estate | 2025 |
| MR Brew Limited | Construction | 2025 |
| MR Freight Logistics Ltd | Transport & logistics | 2026 |
| MR Granite Ltd | Construction | 2017 |
| MR Matthews Hair Ltd | Other services | 2020 |
| MR Mobilz Ltd | Wholesale & retail | 2023 |
| MR Paul Super Limited | Real estate | 2005 |
| MR Plumb of Solihull Ltd | Construction | 2014 |
| MR Sprinkles Ltd | Hospitality | 2026 |
| MR Stephen Ward Medical Services Limited | Health & social care | 2020 |
| MR Useful Bathrooms Ltd | Construction | 2018 |
| Mr-Pump Concrete Ltd | Construction | 2023 |
| MRC Surveying Limited | Professional & scientific | 2013 |
| MRE SPV 1 Limited | Construction | 2023 |
| MRE SPV 2 Limited | Construction | 2023 |
| Mreps Trustees (NO.112) Limited | Professional & scientific | 2003 |
| MRF Foods Ltd | Hospitality | 2022 |
| MRM Assets Ltd | Real estate | 2025 |
| MRM Interiors Ltd | Other services | 2016 |
| MRS Kay's Property Services Ltd | Hospitality | 2021 |
| MRT Interiors (UK) Limited | Administrative & support | 2008 |
| MS Gladstone Ltd | Real estate | 2026 |
| MS Kitchens-Interiors Design & Build Ltd | Wholesale & retail | 2016 |
| MS Mags Limited | Information & communication | 2016 |
| MS Management Ltd | Professional & scientific | 2019 |
| MSI Refrigeration Limited | Manufacturing | 2010 |
| MSJ Assessments Ltd | Professional & scientific | 2025 |
| MSM Flooring Services Limited | Construction | 2007 |
| MSM Landscaping Limited | Administrative & support | 2022 |
| Msma Capital Ltd | Professional & scientific | 2025 |
| Msma Practice Limited | Health & social care | 2025 |
| Msmithers Consultancy Ltd | Information & communication | 2023 |
| Mssridevi Limited | Information & communication | 2019 |
| MSW Real Estate Limited | Real estate | 2023 |
| MT & JF Properties Ltd | Real estate | 2026 |
| MT Construction Midlands Limited | Construction | 2024 |
| MT Rail Support Limited | Transport & logistics | 2017 |
| MTB ROV Services Ltd | Professional & scientific | 2019 |
| MTE Machinetools UK Ltd | Administrative & support | 2018 |
| Mter Vans and Servicing Ltd | Construction | 2023 |
| MTJ Transport Limited | Transport & logistics | 2025 |
| MTL Residential Limited | Professional & scientific | 1998 |
| Mtnt Limited | Real estate | 2019 |
| MTR Holdings Limited | Financial services | 2025 |
| MTR Tyres Ltd | Wholesale & retail | 2014 |