| Multiyork Properties Ltd | Real estate | 2024 |
| Mumford Machinery Limited | Construction | 1981 |
| Munch Matters Limited | Information & communication | 2002 |
| Munch PIT Limited | Hospitality | 2025 |
| Munchin Ltd | Hospitality | 2023 |
| Munghai Limited | Professional & scientific | 2023 |
| Muni Construction Limited | Wholesale & retail | 2026 |
| Munin Air Tech Ltd | Information & communication | 2025 |
| Munoz GAS Solutions Limited | Construction | 2023 |
| Muntaaliz Investment Ltd | Real estate | 2024 |
| Munzkitchen Ltd | Hospitality | 2026 |
| Muqu Ltd | Administrative & support | 2015 |
| Murch Consultancy Ltd | Professional & scientific | 2015 |
| Murphy & Nylander Developments Ltd | Real estate | 2025 |
| Murphy Property Investments Limited | Real estate | 2015 |
| Murphy Reid Property Maintenance Ltd | Construction | 2022 |
| Murphyreid Property Ltd | Households | 2025 |
| Murrban Limited | Professional & scientific | 2016 |
| Musa Kebabs Limited | Hospitality | 2015 |
| Musdi Ltd | Transport & logistics | 2019 |
| Museum of Cultural Arts (Moca UK) Limited | Arts & recreation | 2014 |
| Music on the March (1952) Limited | Arts & recreation | 2007 |
| Music Store Professional UK / DV247 Limited | Wholesale & retail | 2013 |
| Musik Glow Limited | Wholesale & retail | 2022 |
| Muslim Sports Network CIC | Education | 2024 |
| Muslum Baba Ltd | Construction | 2021 |
| Muso Kebab Limited | Hospitality | 2026 |
| Mustafa Group Limited | Wholesale & retail | 2025 |
| Muziris Ltd | Hospitality | 2012 |
| MV Builders Limited | Construction | 2016 |
| MV First Travel Ltd | Administrative & support | 2008 |
| MVA Collective Ltd | Professional & scientific | 2025 |
| MVA Transportation Ltd | Transport & logistics | 2020 |
| Mvdj Cleaning Services Limited | Administrative & support | 2023 |
| MVL Construction Ltd | Construction | 2026 |
| Mvmautotrader Limited | Wholesale & retail | 2024 |
| MVS Developments (Linver) Ltd | Construction | 2021 |
| MVT Transport Ltd | Transport & logistics | 2018 |
| MW Chauffeurs Ltd | Transport & logistics | 2025 |
| MW Safeguard Services Ltd | Financial services | 2024 |
| Mwaddie Healthcare Ltd | Health & social care | 2014 |
| MWB Building Services Limited | Construction | 2022 |
| MWD Partnership Limited | Education | 2022 |
| MWG Polishing Ltd | Construction | 2019 |
| MX Facades Ltd | Construction | 2024 |
| MX Service Engineers Limited | Manufacturing | 2023 |
| MX3J Holding Ltd | Real estate | 2020 |
| Mxtransfer Limited | Information & communication | 2017 |
| My Candy Stop Ltd | Wholesale & retail | 2024 |
| My Digital Dojo Limited | Information & communication | 2026 |
| My Flex Ltd | Wholesale & retail | 2019 |
| My Hairdressers Limited | Extraterritorial | 2015 |
| My Local Locksmith Ltd | Administrative & support | 2025 |
| My Locol Ltd | Information & communication | 2014 |
| My Perfect Productions Ltd | Information & communication | 2026 |
| My Premium Deals Limited | Wholesale & retail | 2017 |
| My Romford Barber Ltd | Other services | 2026 |
| My Shea Limited | Manufacturing | 2011 |
| My Spanish Lesson Limited | Education | 2019 |
| My Tasty Kebab Ltd | Hospitality | 2019 |
| My THS Infra Limited | Wholesale & retail | 2025 |
| My Trini Shop Ltd | Wholesale & retail | 2020 |
| My World Ltd | Agriculture & fishing | 2021 |
| Myacc Solutions Limited | Construction | 2021 |
| Myanmar Limited | Wholesale & retail | 2014 |
| Mybusinessflight Ltd | Administrative & support | 2020 |
| Mycanimations Ltd | Information & communication | 2024 |
| Mycare Solutions Ltd. | Health & social care | 2016 |
| Mycelium Capital Ltd | Financial services | 2022 |
| Myhealthpro Limited | Health & social care | 2024 |
| Mykola Painting & Decorating Ltd | Construction | 2024 |
| Mykraft Solutions Ltd | Construction | 2015 |
| Myleafex Ltd | Other services | 2012 |
| Mylentis Limited | Wholesale & retail | 2025 |
| Mylikemi Limited | Real estate | 2016 |
| Mymove Properties Limited | Real estate | 2021 |
| Mynard Properties Limited | Real estate | 2026 |
| Myne Enterprises Limited | Manufacturing | 2018 |
| Myne London Limited | Manufacturing | 2018 |
| Myownaccountingservices Limited | Professional & scientific | 2015 |
| MYP Consulting Limited | Professional & scientific | 2013 |
| Myphone Shield Ltd | Wholesale & retail | 2025 |
| Myriad Holdings Ltd | Real estate | 2025 |
| Mystar Properties Limited | Hospitality | 2024 |
| MYT Accounting Ltd | Professional & scientific | 2016 |
| MYT Blenmans Ltd | Real estate | 2023 |
| Mytk Limited | Real estate | 2023 |
| MZ & Tech Ltd | Wholesale & retail | 2019 |
| MZA Consulting Limited | Information & communication | 2024 |
| N & B Asset Ltd | Real estate | 2024 |
| N & B Holdings Limited | Real estate | 2020 |
| N & C Building Products Limited | Manufacturing | 1856 |
| N a Hayes Ltd | Other services | 2015 |
| N Bajwa Traders Limited | Wholesale & retail | 2025 |
| N Consultant Ltd | Professional & scientific | 2025 |
| N Formwork Limited | Construction | 2024 |
| N G Tiling Ltd | Construction | 2025 |
| N H Construction Works Ltd | Construction | 2026 |
| N K Wood Builder Ltd | Construction | 2018 |
| N M J Electrical Limited | Construction | 2024 |