| Mitcham Colombo Restaurant Limited | Hospitality | 2017 |
| Mitcham Common Education Trust | Education | 2001 |
| Mitcham Crash Repairs Ltd | Wholesale & retail | 2023 |
| Mitcham Cricket Green Community & Heritage | Other services | 2003 |
| Mitcham DRY Clean and Laundrette Ltd | Other services | 2025 |
| Mitcham Fast Food Ltd | Hospitality | 2024 |
| Mitcham Fried Chicken Ltd | Hospitality | 2026 |
| Mitcham Garden Centre Limited | Wholesale & retail | 2015 |
| Mitcham Hot Winx Ltd | Hospitality | 2024 |
| Mitcham Laundry Ltd | Other services | 2025 |
| Mitcham Nails Ltd | Other services | 2025 |
| Mitcham Phone & Vape Ltd | Wholesale & retail | 2025 |
| Mitcham Physiotherapy Ltd | Health & social care | 2011 |
| Mitcham Service Station LLP | | 2017 |
| Mitcham Superb Pizza Ltd | Hospitality | 2024 |
| Mitcham Tamil Welfare Centre | Education | 2015 |
| Mitcham Tyre Masters Limited | Wholesale & retail | 2025 |
| Mitcham Tyres Ltd | Wholesale & retail | 2018 |
| Mitcham Village Nails Limited | Other services | 2014 |
| Mitcham Village Schoolhouse Limited | Households | 1995 |
| Mitcham ZOO Ltd | Agriculture & fishing | 2021 |
| MIX Building & Removal Ltd | Construction | 2026 |
| Miyama London Limited | Wholesale & retail | 2023 |
| MJ Home Design Ltd | Real estate | 2024 |
| Mjforbes Ltd | Real estate | 2025 |
| MJJ Contracting Ltd | Construction | 2018 |
| MK Naggayi Limited | Health & social care | 2013 |
| Mksp Limited | Wholesale & retail | 2026 |
| MM Cars (Service) Ltd | Transport & logistics | 2024 |
| MM Cars Limited | Transport & logistics | 2025 |
| Mmcleansky Consultants Ltd | Public administration | 2022 |
| MN Brands Ltd | Wholesale & retail | 2023 |
| MNJ Construction Ltd | Construction | 2025 |
| MNK Legal Ltd | Professional & scientific | 2024 |
| Mobile & Laptop Repairs Limited | Wholesale & retail | 2019 |
| Mobile Optical Services Ltd | Health & social care | 2016 |
| Mobile Vision Services Ltd | Health & social care | 2024 |
| Mocn Company Ltd. | Professional & scientific | 2011 |
| Mods Clean LUX Ltd | Wholesale & retail | 2026 |
| Mohe Ltd | Real estate | 2024 |
| Mokob Ltd | Wholesale & retail | 2019 |
| Molaj Limited | Health & social care | 2022 |
| Mollie's Childcare Limited | Health & social care | 2023 |
| Momand Investment Limited | Real estate | 2024 |
| Momarest Ltd | Hospitality | 2025 |
| Monas 1973 Limited | Transport & logistics | 2025 |
| Monett Initiatives Consultancy Limited | Health & social care | 2016 |
| Money Linguo LP | | 2018 |
| Money Malik Management Limited | Professional & scientific | 2021 |
| Montgomery Close 1961 Limited | Extraterritorial | 2013 |
| Mooma Limited | Hospitality | 2020 |
| Moon Video Ltd | Professional & scientific | 2014 |
| Moonlit Moors Limited | Health & social care | 2026 |
| More for Trade Limited | Transport & logistics | 2006 |
| Morlink Ltd | Health & social care | 2022 |
| Morocco UK Society | Health & social care | 2024 |
| Morris Crep Cleaning Limited | Other services | 2025 |
| Moss 101 Ltd | Health & social care | 2020 |
| Moss Quality Construction Ltd | Construction | 2018 |
| Mothers House 105 Limited | Wholesale & retail | 2025 |
| Moto Golden Hands Ltd | Construction | 2024 |
| Motor Vale Limited | Wholesale & retail | 2016 |
| Mototeck Limited | Wholesale & retail | 2024 |
| Moudest Limited | Manufacturing | 2026 |
| Mountain View Property Agents Ltd | Real estate | 2019 |
| Mountainwall Limited | Professional & scientific | 2025 |
| Move&Storage Ltd | Transport & logistics | 2025 |
| MOVE4BETTER Ltd | Transport & logistics | 2024 |
| Movr Plus Limited | Transport & logistics | 2023 |
| Mowgli Gants Limited | Hospitality | 2025 |
| MP Global Ltd | Administrative & support | 2022 |
| MP Perfect Construction Ltd | Construction | 2016 |
| MQ Tradeco Ltd | Wholesale & retail | 2022 |
| MR Singhz Properties Ltd | Real estate | 2020 |
| MRU Community Health Centre CIC | Professional & scientific | 2024 |
| Mrvp Ltd | Hospitality | 2021 |
| MS Classics Ltd | Wholesale & retail | 2020 |
| MS Glass and Glazing Ltd | Construction | 2021 |
| MS Leung Ltd | Information & communication | 2015 |
| MS Powersports Ltd | Wholesale & retail | 2018 |
| MT Health Services Limited | Health & social care | 2023 |
| MTB Upper Green Ltd | Wholesale & retail | 2021 |
| MTH Global Ltd | Transport & logistics | 2025 |
| MTL Trade Ltd | Wholesale & retail | 2025 |
| MTP Enterprise Ltd | Education | 2025 |
| MTS Chaudhary Ltd | Wholesale & retail | 2025 |
| MTW Hospitality Ltd | Hospitality | 2025 |
| Mughal & Traders Ltd | Wholesale & retail | 2025 |
| Muhammad Yousaf Limited | Real estate | 2020 |
| MUJAHIDECOMMERCE786 Ltd | Wholesale & retail | 2024 |
| Mukasi Spice Limited | Hospitality | 2024 |
| Multi Activity & Sport Specialists Ltd | Education | 2022 |
| Multi Dimensions Ltd | Wholesale & retail | 2020 |
| MULTISPORTS4ALL Limited | Education | 2023 |
| Munal Distinction Ltd | Administrative & support | 2022 |
| Muneefa Medical Ltd | Health & social care | 2017 |
| Muni Thatcham Ltd | Real estate | 2025 |
| Muru Removals & Transport Ltd | Transport & logistics | 2025 |
| Musaip Ltd | Hospitality | 2020 |
| Muzah Construction Ltd | Construction | 2015 |