| MUS Takeaway Limited | Hospitality | 2020 |
| Musa DUA Limited | Hospitality | 2023 |
| Musan Couriers Limited | Transport & logistics | 2020 |
| Muscalu Limited | Administrative & support | 2020 |
| Muscle & Chrome Limited | Wholesale & retail | 2018 |
| Muscle & Chrome Paintwork Limited | Construction | 2026 |
| Muscle Grip Ltd | Wholesale & retail | 2020 |
| Mush Health Care Ltd | Health & social care | 2020 |
| Mushroom Lighting Technology Limited | Professional & scientific | 2014 |
| Music Entertainment Ltd | Information & communication | 2018 |
| Musico Productions Limited | Administrative & support | 1977 |
| Musicpsych Ltd | Professional & scientific | 2010 |
| Muslyt Ltd | Health & social care | 2016 |
| Mussa Khalid Company Ltd | Transport & logistics | 2017 |
| Mustafa (M) Ltd | Extraterritorial | 2015 |
| Mustang Supply Ltd | Wholesale & retail | 2014 |
| Mustorderit.Com Ltd | Wholesale & retail | 2010 |
| Muszczak Closing Ltd | Professional & scientific | 2022 |
| Mutabilis Music Limited | Manufacturing | 2010 |
| Mutruc Solutions Ltd | Construction | 2014 |
| Mutu Trans Ltd | Transport & logistics | 2013 |
| MV Beauty Limited | Other services | 2014 |
| MV Car Wash Ltd | Wholesale & retail | 2026 |
| MV Interiors Limited | Construction | 2023 |
| MV Plumbing Ltd | Construction | 2018 |
| MV Residential Group Limited | Real estate | 2026 |
| MVC IT Consultancy Ltd | Information & communication | 2012 |
| MVG Drylining Ltd | Construction | 2025 |
| MVS Pizza Ltd | Hospitality | 2014 |
| MVS Property Management Limited | Real estate | 2019 |
| Mvstb Limited | Transport & logistics | 2024 |
| MW Estates Northampton Limited | Construction | 2018 |
| MW Integrated Systems Limited | Administrative & support | 2009 |
| MW Northampton Limited | Real estate | 2016 |
| MW Properties Northampton Ltd | Construction | 2017 |
| MW Sourcing Ltd | Real estate | 2026 |
| Mwana Cholowa Limited | Real estate | 2020 |
| MWE Media Ltd | Information & communication | 2009 |
| MWH Group Ltd | Real estate | 2022 |
| MWH Wine Merchants Limited | Wholesale & retail | 2006 |
| MWK Architects Ltd. | Professional & scientific | 2014 |
| MWK Holdings Ltd. | Professional & scientific | 2019 |
| MWW Property Investments Limited | Real estate | 2024 |
| MWZ Holdings Limited | Households | 2023 |
| MXA Scandinavia Limited | Mining & quarrying | 2010 |
| Mxology Limited | Professional & scientific | 2020 |
| MXV Courier NN3 Limited | Transport & logistics | 2026 |
| My 1ST Years Limited | Wholesale & retail | 2017 |
| My Beautiful Green Limited | Wholesale & retail | 2016 |
| My Care Consortium Ltd | Health & social care | 2025 |
| My Cliniq Ltd | Health & social care | 2022 |
| My Coach Hire Ltd | Transport & logistics | 2024 |
| My Digital House Ltd | Wholesale & retail | 2020 |
| My Dream Wardrobes Ltd | Manufacturing | 2019 |
| My Family Care Limited | Administrative & support | 2006 |
| My Great First JOB CIC | Education | 2019 |
| My GUY Logistics Ltd | Transport & logistics | 2025 |
| My Haven Properties Limited | Households | 2024 |
| My Home My Companion Limited | Health & social care | 2019 |
| My Key Health Ltd | Health & social care | 2020 |
| My Medi Health Care Ltd | Health & social care | 2023 |
| My Notebook Ltd | Wholesale & retail | 2025 |
| My PAD Property Management Ltd | Real estate | 2021 |
| My Profit Limited | Extraterritorial | 2024 |
| My Property Care Ltd | Real estate | 2020 |
| My Talent Brand Recruitment Limited | Administrative & support | 2020 |
| My Taxee Ltd | Transport & logistics | 2023 |
| My TRI3E Ltd | Health & social care | 2024 |
| My Unique Treasures Ltd | Wholesale & retail | 2020 |
| MYA Clinics Ltd | Health & social care | 2017 |
| Mybackend Limited | Information & communication | 2024 |
| Mybalkans Limited | Transport & logistics | 2020 |
| Mycart Limited | Construction | 2017 |
| Mycelium Limited | Manufacturing | 1997 |
| Mycol Limited | Health & social care | 2013 |
| Mycomms Ltd | Information & communication | 2014 |
| Mycompanyuk Ltd | Wholesale & retail | 2019 |
| Mydreamhorse Ltd | Agriculture & fishing | 2021 |
| Myka Ltd | Wholesale & retail | 2022 |
| Myka SCP Limited | Hospitality | 2026 |
| Myka UK CG Limited | Hospitality | 2026 |
| Myka UK Holdings Limited | Hospitality | 2026 |
| Mykova Consulting Ltd | Professional & scientific | 2026 |
| Myla and Haris Care Limited | Health & social care | 2020 |
| Mylastrequest Limited | Professional & scientific | 2016 |
| Myotgo Tech Ltd | Wholesale & retail | 2025 |
| Myownconference Ltd | Information & communication | 2017 |
| Mypackbrain Limited | Information & communication | 2012 |
| Myriad Asset Management Limited | Real estate | 2011 |
| Myriad Construction Solutions Limited | Construction | 2010 |
| Mysera Ltd | Wholesale & retail | 2025 |
| Mystery Tour Productions Ltd | Arts & recreation | 2025 |
| Mystical Lighting Limited | | 1985 |
| Myth Play Ltd | Arts & recreation | 2020 |
| Mythical Creatures Limited | Extraterritorial | 2014 |
| Mytinyworld Distribution Limited | Other services | 2009 |
| Mytinyworld Limited | Wholesale & retail | 2008 |
| Mytinyworld Property Limited | Other services | 2008 |
| Mytruessence Ltd | Professional & scientific | 2009 |
| Myumbrella Ltd | Administrative & support | 2017 |