| Mazz Properties Ltd | Real estate | 2016 |
| Maz’S Drive Ltd | Education | 2025 |
| MB Carpets and Tiles Ltd | Construction | 2024 |
| MB Timing Limited | Arts & recreation | 2017 |
| MBA Developments Limited | Construction | 2026 |
| MBA Properties Group Ltd | Real estate | 2025 |
| MBB Investment Ltd | Health & social care | 2022 |
| Mbcc Awards Ltd | Professional & scientific | 2021 |
| Mbdin Limited | Transport & logistics | 2012 |
| MBM Digital Media Limited | Information & communication | 2026 |
| Mboss Creations Ltd | Manufacturing | 2024 |
| MBS Interiors (SOT) Ltd | Construction | 2023 |
| MBT Stoke Ltd | Transport & logistics | 2022 |
| MC & S Transport Ltd | Transport & logistics | 2022 |
| MC Expert Delivery Ltd | Transport & logistics | 2019 |
| MC Fitness Clubs Limited | Financial services | 2025 |
| MC Leisure Holding (UK) Limited | Professional & scientific | 1995 |
| MC Operators Ltd | Construction | 2022 |
| MC Vehicle Finance Limited | Financial services | 2024 |
| Mcare Recruit UK Ltd | Health & social care | 2020 |
| Mcas Delivery Limited | Transport & logistics | 2023 |
| Mcathey Investments Limited | Financial services | 2023 |
| MCB Medical Limited | Health & social care | 2018 |
| MCD Software Development Ltd | Information & communication | 2024 |
| Mcdowall Electrical Ltd | Construction | 2024 |
| MCE Company Holding Limited | Financial services | 2023 |
| Mcguinness Legal Ltd | Professional & scientific | 2012 |
| Mcguinness Metal Merchants Limited | Wholesale & retail | 2021 |
| Mcguinness Scrap Metal Limited | Wholesale & retail | 2021 |
| Mcguinness Scrap Yard Limited | Wholesale & retail | 2021 |
| Mcintosh Accountants Limited | Professional & scientific | 2003 |
| Mcjennings Properties Limited | Real estate | 2026 |
| Mckenzie Friend West Middlands Ltd | Administrative & support | 2023 |
| MCL Industrial Enclosures Ltd | Manufacturing | 1977 |
| Mclarens GAS Services Ltd | Construction | 2021 |
| MCM Wigan Ltd | Real estate | 2025 |
| Mcmason Property Management & Solutions Ltd | Extraterritorial | 2024 |
| Mcnaughton Sims Associates Limited | Professional & scientific | 2018 |
| Mcpenguin Limited | Real estate | 2026 |
| Mcquades Residential Conveyancing Limited | Professional & scientific | 2012 |
| Mcqueens Vehicle Services Ltd | Wholesale & retail | 2022 |
| Mcrystal Ltd | Wholesale & retail | 2023 |
| MCS Marketing Limited | Professional & scientific | 2017 |
| Mcsn Properties Limited | Real estate | 2007 |
| MD Company Holdings Limited | Financial services | 2026 |
| MD Enterprises Ltd | Wholesale & retail | 2025 |
| MD Feature Productions Limited | Information & communication | 2023 |
| MD Kitchens and Bedrooms Limited | Manufacturing | 2023 |
| MD Properties and Leisure Ltd | Arts & recreation | 2019 |
| MD Trendz Ltd | Wholesale & retail | 2024 |
| MDA Contracting Ltd | Construction | 2024 |
| Mdcl Realisations 2024 Limited | Construction | 2012 |
| MDJ Holdco Ltd | Professional & scientific | 2025 |
| Mdjk Properties Limited | Real estate | 2022 |
| MDM Logistics Ltd | Transport & logistics | 2025 |
| MDR Energy Services Limited | Professional & scientific | 2012 |
| MDS Properties 2014 Limited | Real estate | 2014 |
| Me-Installations Limited | Construction | 2009 |
| MEA Developments Limited | Construction | 2022 |
| Meadons Holdings 3 Limited | Financial services | 2019 |
| Meadow View (Alsager) Management Company Limited | Households | 2019 |
| Meadows Property Group Ltd | Real estate | 2022 |
| Meaford Fields Day Nursery Ltd | Health & social care | 2016 |
| Meaford Food and Wine Ltd | Wholesale & retail | 2025 |
| Meath Build Ltd | Construction | 2017 |
| Meath Developments Ltd | Real estate | 2016 |
| MEB Total Limited | Construction | 2004 |
| Mecanicles Car & Machine Ltd | Wholesale & retail | 2026 |
| Mechanical Design Services Ltd | Professional & scientific | 2018 |
| Mechtron by Perfect Cars Kerala UK Ltd | Wholesale & retail | 2026 |
| MED Professionals Limited | Health & social care | 2019 |
| Mede Developments Ltd | Real estate | 2025 |
| Medeea Logistics Ltd | Transport & logistics | 2018 |
| Medexcellence Ltd | Education | 2024 |
| Medi Pick Ltd | Transport & logistics | 2025 |
| Medi-Dashboard Ltd | Information & communication | 2024 |
| Media Digital Limited | Financial services | 2024 |
| Media Lanka NET Work Limited | Information & communication | 2017 |
| Media Marshall Ltd | Information & communication | 2023 |
| Media Outreach Limited | Professional & scientific | 2019 |
| Mediaffy Ltd | Information & communication | 2026 |
| Mediaz Entertainment Limited | Wholesale & retail | 2025 |
| Medic Route Ltd | Health & social care | 2026 |
| Medical Health Experts Ltd | Health & social care | 2025 |
| Medical Works Ltd | Health & social care | 2009 |
| Medicals 4 Drivers Ltd | Other services | 2019 |
| Medicas Curas Limited | Health & social care | 2018 |
| Medicines for Life Limited | Wholesale & retail | 2001 |
| Medicura Limited | Health & social care | 2013 |
| Mediglobal Locum Specialist Ltd | Health & social care | 2023 |
| Medihelpuk Ltd | Health & social care | 2013 |
| Medina Dini Limited | Health & social care | 2024 |
| Medina Estates Ltd | Real estate | 2026 |
| Medina Kidsgrove Ltd | Hospitality | 2025 |
| Medprom Limited | Construction | 2016 |
| Medrova Ltd. | Information & communication | 2026 |
| Meds Utilities Ltd | Energy | 2018 |
| Meduza Retail Limited | Wholesale & retail | 2025 |
| Meerkat Applications Limited | Information & communication | 2007 |
| Mega Goods Ltd | Wholesale & retail | 2026 |