| MC Site Solutions Ltd | Transport & logistics | 2026 |
| MC Solver Limited | Other services | 2019 |
| MC. Squared Music Limited | Arts & recreation | 1987 |
| MCA First AID Training and Event Cover Limited | Health & social care | 2017 |
| Mcae Limited | Professional & scientific | 2013 |
| Mccabes Coatings Ltd | Construction | 2024 |
| Mccann Homes (Edlesborough) Limited | Construction | 2014 |
| Mccann Homes (MK) Ltd | Construction | 2009 |
| Mccarthy Skin and Beauty Ltd | Other services | 2025 |
| Mccarthy Skin Clinic Ltd. | Other services | 2013 |
| Mccolley Comm Ltd | Information & communication | 2024 |
| Mcconnell Gunn Ltd | Real estate | 2025 |
| Mccsmiths Ltd | Wholesale & retail | 2023 |
| Mccue Corporation Limited | Wholesale & retail | 2013 |
| Mcdowell Prescott Limited | Extraterritorial | 2021 |
| Mcford Estates Ltd | Real estate | 2023 |
| MCG Limited | Wholesale & retail | 2023 |
| Mcgregor Cory Limited | Transport & logistics | 1953 |
| MCH Dynamics Ltd | Wholesale & retail | 2022 |
| Mciod Limited | Construction | 2009 |
| MCL Auto Ltd | Manufacturing | 2024 |
| Mcloughlin Homes Ltd | Construction | 2018 |
| MCM Transport Limited | Transport & logistics | 2026 |
| Mcmac Ltd | Information & communication | 2019 |
| Mcmanus & Family Ltd | Real estate | 2021 |
| Mcmanus Transport Contracting Ltd | Transport & logistics | 2024 |
| Mcneill Lowe & Palmer Surveyors Ltd | Professional & scientific | 2011 |
| Mconduah Limited | Financial services | 2012 |
| MCR Construction Ltd | Construction | 2015 |
| MCR Management Services Ltd | Construction | 2019 |
| MCR Shopfitting Ltd | Administrative & support | 2016 |
| MCS Electrical Contracting Ltd | Construction | 2024 |
| MCS Emerald Ltd | Administrative & support | 2020 |
| MCS House Limited | Construction | 2022 |
| Mcsherry Cookware Ltd | Wholesale & retail | 2025 |
| Mcstephen Electrical Limited | Wholesale & retail | 2025 |
| MCT Green Clean Ltd | Administrative & support | 2025 |
| MCT Lifesciences Ltd | Manufacturing | 2019 |
| Mczone Limited | Wholesale & retail | 2025 |
| MD Bricklayer Ltd | Construction | 2018 |
| MD Commercial Ltd | Construction | 2015 |
| MD Govier (Electrical Engineering) Ltd | Construction | 2011 |
| MD Link Shop Ltd | Wholesale & retail | 2026 |
| MD Maintenance Ltd | Transport & logistics | 2025 |
| MD Plumbing Ltd | Construction | 2021 |
| MD Pro Global Ltd | Transport & logistics | 2024 |
| MDC Precision Limited | Manufacturing | 2009 |
| MDD Enterprises Ltd | Wholesale & retail | 2013 |
| Mdea Communications Limited | Administrative & support | 2013 |
| Mdecorr Ltd | Other services | 2026 |
| MDG Professional Services Ltd | Financial services | 2010 |
| MDL Ventilation Ltd | Construction | 2021 |
| MDM Construction Ltd | Construction | 2018 |
| Mdne Business Solutions Limited | Professional & scientific | 2014 |
| MDP & Training Ltd | Professional & scientific | 2020 |
| MDP Trustees Limited | Administrative & support | 2009 |
| Mdsra Limited | Information & communication | 2015 |
| MDT Solutions Limited | Construction | 2023 |
| ME Consultant Ltd | Professional & scientific | 2017 |
| ME Marketing YOU Ltd | Professional & scientific | 2025 |
| Me-Eddy Ltd | Transport & logistics | 2019 |
| Mead Open Farm Day Nursery Limited | Health & social care | 2016 |
| Mead Property Limited | Real estate | 2017 |
| Meadow Bay Villages Manco Limited | Arts & recreation | 2024 |
| Meadow Medics Limited | Health & social care | 2007 |
| Meadow Nest Limited | Real estate | 2025 |
| Meadow View (Whitehouse) Management Company Limited | Construction | 2025 |
| Meadows House Management Company Limited | Administrative & support | 2025 |
| Meat & Heat Ltd | Hospitality | 2025 |
| Meaty Parts Ltd | Wholesale & retail | 2018 |
| MEATYCAMB1 Ltd | Hospitality | 2024 |
| Meba Healthcare Ltd | Administrative & support | 2022 |
| Mecelec Design Limited | Professional & scientific | 1989 |
| Mechide Limited | Wholesale & retail | 2025 |
| Mechline Developments Limited | Manufacturing | 1991 |
| Mechline Holdings Limited | Hospitality | 2016 |
| Mechworks Engineering Ltd | Construction | 2025 |
| Mecky Solutions Ltd | Manufacturing | 2023 |
| Meclec Limited | Administrative & support | 2006 |
| Mecodex Recruitment Limited | Health & social care | 2023 |
| MED Deli Food Ltd | Wholesale & retail | 2017 |
| Med-Colloid Ltd | Other services | 2023 |
| Meda Technologies Limited | Administrative & support | 2000 |
| Medallion Resources Ltd | Real estate | 2024 |
| Medavarapu Properties Ltd | Real estate | 2019 |
| Medco Recruitment Limited | Health & social care | 2016 |
| Medco Registration Solutions | Administrative & support | 2014 |
| Medcore Investment Ltd | Real estate | 2017 |
| Medexia Ltd | Information & communication | 2026 |
| Medford Logistics Ltd | Transport & logistics | 2026 |
| Medhealth Pharma Consulting Firm Ltd | Health & social care | 2019 |
| Medi Global Care Ltd | Health & social care | 2021 |
| Medi Team Recruitment Ltd | Administrative & support | 2016 |
| Media Bubble Ltd | Information & communication | 2016 |
| Media Iglobal Partners LLP | | 2025 |
| Media Medical Services Limited | Administrative & support | 2021 |
| Medialis Limited | Professional & scientific | 2014 |
| Mediapool Japan Limited | Extraterritorial | 2017 |
| Medical Care Supplies Limited | Wholesale & retail | 2011 |
| Medical Detection Dogs | Professional & scientific | 2007 |