| Mushkil Asaan Transport CIC | Transport & logistics | 2024 |
| Music Against Racism CIC | Education | 2024 |
| Music Quay Limited | Arts & recreation | 2017 |
| Musical Accountants Limited | Professional & scientific | 2013 |
| Musket House Management Company Limited | Households | 2026 |
| Musson Melia Music Ltd | Arts & recreation | 2025 |
| Must Have Entertainment Ltd | Arts & recreation | 2021 |
| Mustafa Abdulhusain T/A Kcure Ltd | Professional & scientific | 2011 |
| Mustang Builders Limited | Construction | 2026 |
| Mutation Park (Film) Ltd | Information & communication | 2025 |
| Mutivili Promotions Ltd | Administrative & support | 2018 |
| Muvenow Limited | Information & communication | 2025 |
| Muxsad Investment Limited | Real estate | 2019 |
| Muzaam IT Limited | Information & communication | 2021 |
| Muzammil Sher Limited | Wholesale & retail | 2022 |
| Muzika Limited | Administrative & support | 2010 |
| MV Consultancy Services Limited | Administrative & support | 2024 |
| MV Lanway Limited | Construction | 2009 |
| MV Property (UK) Limited | Professional & scientific | 1998 |
| MV Test Solutions Limited | Information & communication | 2019 |
| MV1 Services Limited | Transport & logistics | 2023 |
| MV2 Holding Ltd | Financial services | 2024 |
| MVB Project Management Ltd | Professional & scientific | 2023 |
| Mvcs Holdco Ltd | Financial services | 2024 |
| Mvcs Property Ltd | Financial services | 2024 |
| MVE Engineering Ltd | Professional & scientific | 2012 |
| MVN Building Ltd | Construction | 2026 |
| MVP Investment Holdings Limited | Professional & scientific | 2012 |
| MVS Drylining Ltd | Construction | 2018 |
| Mvsk Investments Ltd | Real estate | 2018 |
| MVT Telecom Ltd | Information & communication | 2021 |
| MVV Enterprise Limited | Information & communication | 2013 |
| MW Block Management Limited | Real estate | 2015 |
| Mw-Labs Ltd | Information & communication | 2021 |
| Mwafrika Limited | Administrative & support | 2020 |
| MWD Direct Limited | Wholesale & retail | 2012 |
| MWF Consulting Limited | Professional & scientific | 2025 |
| MWG Holdings Limited | Financial services | 2022 |
| MWG Innovations Limited | Construction | 2020 |
| MWG Management Limited | Construction | 2022 |
| MWM Building Contractors Ltd | Construction | 2024 |
| Mwtrans Ltd | Transport & logistics | 2024 |
| MX Restaurant Ltd | Hospitality | 2025 |
| MXE Limited | Wholesale & retail | 2025 |
| MXM Associates Limited | Health & social care | 2021 |
| MXP Associates Limited | Professional & scientific | 2016 |
| MXT Services Ltd | Construction | 2023 |
| My Academy Limited | Information & communication | 2024 |
| My Beach Retreat Ltd | Transport & logistics | 2021 |
| My Beautiful Wigs Limited | Wholesale & retail | 2020 |
| My Brain MAP Ltd | Professional & scientific | 2025 |
| My Bright Smiles Ltd | Health & social care | 2024 |
| My Cake Supplies Limited | Wholesale & retail | 2016 |
| My Car Glass Ltd | Wholesale & retail | 2003 |
| My Coach Limited | Transport & logistics | 2010 |
| My Endless Essentials Ltd | Wholesale & retail | 2022 |
| My Eyedentity Ltd. | Real estate | 2015 |
| My Global Training Academy Limited | Administrative & support | 2024 |
| My Grace Designs Ltd | Information & communication | 2021 |
| My Holiday News Ltd | Manufacturing | 2024 |
| My Home Props Ltd | Real estate | 2024 |
| My I-Life Limited | Administrative & support | 2024 |
| My Intelligent Health Ltd | Information & communication | 2022 |
| My Leadership Coaching Ltd | Professional & scientific | 2025 |
| My LOW Carbon Life CIC | Professional & scientific | 2021 |
| My Marketing Ltd | Information & communication | 2014 |
| My New Home London Limited | Real estate | 2021 |
| My New Space Ltd | Real estate | 2015 |
| My Presidential World Limited | Wholesale & retail | 2019 |
| My Real Estate Limited | Real estate | 2022 |
| My Revue Ltd | Wholesale & retail | 2025 |
| My Skin and ME Ltd | Other services | 2022 |
| My Smart Academy Limited | Education | 2025 |
| My SOL Ltd | Information & communication | 2010 |
| My Sweet Home Ltd | Real estate | 2025 |
| My Tool Hire Ltd | Administrative & support | 2019 |
| My Trawler Ltd | Transport & logistics | 2025 |
| My Way Limited | Wholesale & retail | 2022 |
| My Workspace Argyle Street Ltd | Real estate | 2022 |
| My Workspace Barnsley Road Limited | Real estate | 2022 |
| My Workspace Hatrack Ltd | Real estate | 2019 |
| My Workspace Hemel Estates Limited | Real estate | 2022 |
| My Workspace Winsor Newton Ltd | Real estate | 2018 |
| Myallergy Limited | Wholesale & retail | 2014 |
| Myatt Developments & Property Lettings LLP | | 2017 |
| MYB Bookkeeping Ltd | Professional & scientific | 2013 |
| Myepychia Limited | Wholesale & retail | 2019 |
| Myers & Levy Limited | Professional & scientific | 2020 |
| Myers Consulting Ltd | Other services | 1999 |
| Myfire Limited | Public administration | 2002 |
| Myinkare Limited | Wholesale & retail | 2022 |
| Myjuno Education Limited | Education | 2024 |
| Mykart Global Ltd | Wholesale & retail | 2025 |
| Mymerch Mart Ltd | Wholesale & retail | 2024 |
| Mymy Transport Ltd | Transport & logistics | 2019 |
| Myna Property Limited | Administrative & support | 2013 |
| Myndatix Solutions Ltd | Information & communication | 2025 |
| Mynewbranch Limited | Administrative & support | 2025 |
| Mynico Ltd | Real estate | 2016 |
| Myra Technology Ltd | Information & communication | 2022 |