| Metal Woods Holdings Limited | Real estate | 1991 |
| Metchley Energy Associates Limited | Professional & scientific | 2016 |
| Metchson Ltd | Professional & scientific | 2012 |
| Meticulous Integrated Solutions Limited | Wholesale & retail | 2025 |
| Metis Executives Ltd | Administrative & support | 2026 |
| Metro Inns (Falkirk) Limited | Real estate | 2006 |
| Metro Minimarket Ltd | Wholesale & retail | 2021 |
| Metro Peri Peri Ltd | Hospitality | 2022 |
| Metro Trada Ltd | Wholesale & retail | 2025 |
| Metrol Springs Limited | Manufacturing | 1985 |
| Metrosameday Limited | Transport & logistics | 2017 |
| Mevolution Consulting Ltd | Professional & scientific | 2025 |
| Mews Court Pattishall Management Limited | Households | 2023 |
| Mextru Limited | Manufacturing | 2006 |
| Meyer-Scott Recruitment Limited | Administrative & support | 2013 |
| MF Rahman & Bros Ltd | Real estate | 2021 |
| MFA Property Ltd | Real estate | 2023 |
| MFC Real Estate Ltd | Real estate | 2022 |
| MFF Groupe Ltd | Financial services | 2025 |
| MFK Auto Traders Ltd | Wholesale & retail | 2023 |
| Mfor Associates Limited | Construction | 2000 |
| MG Bookkeeping Ltd | Professional & scientific | 2017 |
| MG DEC Limited | Construction | 2022 |
| MG Heating Engineers Ltd | Professional & scientific | 2021 |
| MG Loads Ltd | Transport & logistics | 2025 |
| MG Painting Ltd | Construction | 2016 |
| MG Signs Ltd | Manufacturing | 2025 |
| MG Tax & Accounting Services Ltd | Professional & scientific | 2024 |
| MG Trans Services Ltd | Transport & logistics | 2025 |
| MG Window Systems Ltd | Construction | 2002 |
| MGA Always on Time Ltd | Transport & logistics | 2019 |
| MGA Training Limited | Education | 2008 |
| MGI Consult Ltd | Information & communication | 2026 |
| Mgjones Limited | Hospitality | 2024 |
| MGK Drivers Ltd | Transport & logistics | 2015 |
| MGK Telecoms Limited | Professional & scientific | 2023 |
| MGL Electrical Services Ltd | Other services | 2015 |
| MGL Spedition Ltd | Transport & logistics | 2025 |
| MGM Drivers Limited | Transport & logistics | 2024 |
| MGM Go Limited | Transport & logistics | 2017 |
| MGM Sales Ltd | Wholesale & retail | 2025 |
| MGP Construction Ltd | Construction | 2024 |
| MGR Carpentry Contractors Limited | Manufacturing | 2023 |
| MGV Consulting Limited | Professional & scientific | 2014 |
| MGZ Landlord Services Ltd | Real estate | 2022 |
| MH Aggregates Ltd | Transport & logistics | 2022 |
| MH Driver Ltd | Transport & logistics | 2026 |
| MH GP Services Ltd | Health & social care | 2025 |
| MH Home Renovations Ltd | Construction | 2024 |
| MH Official Ltd | Construction | 2020 |
| MH Services (Kettering) Limited | Construction | 2015 |
| MH Star UK Ltd | Wholesale & retail | 2010 |
| MH Stonex Homes Ltd | Construction | 2026 |
| MH Tech Centre Limited | Wholesale & retail | 2017 |
| MH288 Ltd | Hospitality | 2022 |
| MHL Management Limited | Households | 2026 |
| MHM Pipework Ltd | Other services | 2026 |
| MHR Holdings Limited | Real estate | 2021 |
| MHR People First Limited | Professional & scientific | 1999 |
| Mhrenterprise Ltd | Wholesale & retail | 2026 |
| Mhull Joinery Ltd | Construction | 2015 |
| MI Fruit & VEG Ltd | Wholesale & retail | 2023 |
| MI Recruitment (Npton) Ltd | Administrative & support | 2024 |
| Mi-Nic-Trans Limited | Transport & logistics | 2014 |
| MI60 Ltd | Construction | 2025 |
| MIA Creative Design Ltd | Professional & scientific | 2024 |
| Miah & Miah Ltd | Real estate | 2025 |
| Miami FOX Ltd | Arts & recreation | 2023 |
| Miami Tanning Studio (Leamington) Ltd | Other services | 2012 |
| Miami Tanning Studio (Redditch) Ltd | Other services | 2015 |
| Miami Tanning Studio Coventry Limited | Other services | 2017 |
| Mian Enterprise Ltd | Wholesale & retail | 2026 |
| Mias UK Holdings LLP | | 2023 |
| Miask Properties Ltd | Real estate | 2025 |
| MIC Dry-Lining 24/7 Ltd | Construction | 2020 |
| MIC Solutions Ltd | Information & communication | 2014 |
| Mica Cosmetics Ltd | Wholesale & retail | 2021 |
| Micalin Trans Ltd | Transport & logistics | 2026 |
| Micha Nani Ltd | Health & social care | 2022 |
| Michael Anthony Project Management Limited | Information & communication | 2009 |
| Michael Auto Repair Ltd | Wholesale & retail | 2021 |
| Michael Broadhurst Motorsport Limited | Arts & recreation | 2016 |
| Michael David Cars Limited | Wholesale & retail | 2015 |
| Michael Forward Financial Services Limited | Financial services | 2007 |
| Michael Forward Mortgage Services Ltd | Financial services | 2025 |
| Michael J. Blakemore Limited | Professional & scientific | 2009 |
| Michael Kentas & Co Limited | Professional & scientific | 2007 |
| Michael Lynskey Limited | Professional & scientific | 2019 |
| Michael Mallock Ltd | Arts & recreation | 2007 |
| Michael Shaw Media Limited | Information & communication | 2020 |
| Michael Sheridan & Company Limited | Administrative & support | 1983 |
| Michael Thorpe Limited | Professional & scientific | 2022 |
| Michal Kwiecien Ltd | Transport & logistics | 2016 |
| Michela MK Ltd | Construction | 2024 |
| Michelpee Ltd | Transport & logistics | 2020 |
| Michlig Pro Limited | Health & social care | 2019 |
| Micis Barber Shop Ltd | Other services | 2025 |
| Mick and Sons Construct Limited | Construction | 2021 |
| Mick Coare Transport Limited | Transport & logistics | 2014 |
| Mick Vartan Interiors Ltd | Construction | 2013 |