| MJM Glory Limited | Wholesale & retail | 2020 |
| MJP & R Utilities Limited | Energy | 2019 |
| MJP Aspects Limited | Real estate | 2026 |
| MJW Traders Ltd | Education | 2026 |
| MK C Tavern Limited | Real estate | 2026 |
| MK2 Holdings Ltd | Financial services | 2025 |
| Mkatucann Ltd | Hospitality | 2026 |
| Mkhb Estates Ltd | Professional & scientific | 2025 |
| MKV Omega Limited | Other services | 2010 |
| MLK Burgers Cheadle Ltd | Hospitality | 2024 |
| MLK Properties Ltd | Real estate | 2024 |
| Mllr Limited | Financial services | 2008 |
| MMI Properties Northwest Ltd | Real estate | 2024 |
| Mmins (UK) Ltd | Wholesale & retail | 2024 |
| Mmzagh Ltd | Health & social care | 2026 |
| MN Hygienist Ltd | Health & social care | 2008 |
| MNT Property Limited | Real estate | 2015 |
| MO Interiors Limited | Construction | 2024 |
| Mockingbird Projects Limited | Professional & scientific | 2023 |
| Mockingbird Property Limited | Real estate | 2020 |
| MOD Group Holdings Ltd | Financial services | 2026 |
| Modus Operandi Consultancy Ltd | Information & communication | 2019 |
| Modus Operandi Referral Network Ltd | Professional & scientific | 2024 |
| Moelfre Coastal Cafe Limited | Hospitality | 2020 |
| Mohammed ALI EYE Welfare | Health & social care | 2022 |
| Molloy Plant Hire Holdings Limited | Financial services | 2018 |
| Monami Healthy Living Limited | Wholesale & retail | 2020 |
| Moncam Properties Ltd | Real estate | 2023 |
| Money Advice Ltd | Financial services | 2019 |
| Money Advisory Centre Limited | Financial services | 2013 |
| Mono Capital 1178 Limited | Construction | 2024 |
| Mono Capital Holdings Limited | Financial services | 2024 |
| Mono Capital Investments Limited | Financial services | 2022 |
| Mono Capital Limited | Construction | 2019 |
| Mono Capital RE1 Limited | Real estate | 2025 |
| Mono Property Group Ltd | Real estate | 2025 |
| Monopole Magnetics Limited | Real estate | 2024 |
| Mont Developments Ltd | Construction | 2026 |
| Mont Flooring Limited | Construction | 2023 |
| Monton Group Limited | Financial services | 2020 |
| Monty Social Limited | Professional & scientific | 2019 |
| Monty’S Kitchen Ltd | Hospitality | 2024 |
| Moon Creative Design Ltd | Information & communication | 2021 |
| Moon Dates & Incense Ltd | Wholesale & retail | 2025 |
| Moorland Rentals Limited | Real estate | 2025 |
| Mopharmmed Ltd | Wholesale & retail | 2025 |
| Moran Building & Landscapes Limited | Administrative & support | 2021 |
| More Books Limited | Wholesale & retail | 2025 |
| Moreau Enterprises Limited | Hospitality | 2014 |
| Moreit Technologies Ltd | Information & communication | 2019 |
| Moreno Wine Importers Company Limited | Wholesale & retail | 1988 |
| Moreton Croft (Tarvin) Management Company Limited | Households | 2009 |
| Morfi Estates Ltd | Real estate | 2025 |
| Morfi UK Ltd | Health & social care | 2018 |
| Morie UK Ltd | Manufacturing | 2022 |
| Morma Ltd | Wholesale & retail | 2025 |
| Mormac Ltd | Construction | 2024 |
| Morris Gregory Limited | Professional & scientific | 2003 |
| Mortgage Audit Reporting Software Limited | Information & communication | 2015 |
| Moseley Road Productions Ltd | Information & communication | 2018 |
| Mostyn Mill Properties Limited | Real estate | 2021 |
| Motero Sports Limited | Wholesale & retail | 2015 |
| Motion FX Ltd | Information & communication | 2026 |
| Motor Solution 4 U Ltd | Wholesale & retail | 2019 |
| Motorlens Limited | Wholesale & retail | 2024 |
| Mould Prevent UK Ltd | Administrative & support | 2024 |
| Mount Folly Square Management Company Ltd | Households | 2015 |
| Mounteney Conveyancers Limited | Professional & scientific | 2015 |
| Moussa Badry Limited | Wholesale & retail | 2021 |
| Moving Onwards Limited | Real estate | 2020 |
| Moya Cole Hospice | Health & social care | 1969 |
| Moya Cole Hospice Trading Company Limited | Wholesale & retail | 1990 |
| MPG Real Estate Ltd | Real estate | 2023 |
| MRA Flight Training Limited | Transport & logistics | 2022 |
| MRD Property Investments Limited | Professional & scientific | 2023 |
| MRS Whippy’S Ltd | Wholesale & retail | 2023 |
| MS Health Group Ltd | Wholesale & retail | 2024 |
| MS Roshi Limited | Professional & scientific | 2022 |
| Ms.Core Properties Limited | Real estate | 2026 |
| MSA Healthcare Services Limited | Health & social care | 2026 |
| MSA Master Sken Limited | Arts & recreation | 2015 |
| MSB1 Ltd | Real estate | 2019 |
| MSD Electrical and Engineering Services Ltd | Other services | 2018 |
| MSG Cleaners Ltd | Administrative & support | 2026 |
| MSG Online Consultancy Ltd | Professional & scientific | 2015 |
| Mskz Consulting Ltd | Education | 2024 |
| MSL Claims Solutions LLP | | 2012 |
| MSL Legal Expenses Ltd | Financial services | 1988 |
| MSL Vehicle Solutions Limited | Administrative & support | 1979 |
| MSN Training Limited | Information & communication | 2017 |
| MSS Direct Ltd | Professional & scientific | 2026 |
| MST Mere (Properties) Limited | Real estate | 2019 |
| MTD Made Simple Limited | Information & communication | 2025 |
| MTJ Engineering Limited | Professional & scientific | 2019 |
| MTK Pharma Consulting Limited | Information & communication | 2022 |
| Mtma Medical Limited | Health & social care | 2016 |
| MTN Aslan Limited | Hospitality | 2020 |
| Mubashar and Partners Limited | Real estate | 2025 |
| Muddy Vapes Limited | Wholesale & retail | 2024 |
| Mugla Limited | Hospitality | 2021 |