| Mbmb Properties Ltd | Real estate | 2021 |
| MBP Smiles Ltd | Health & social care | 2019 |
| Mbpq Limited | Wholesale & retail | 2021 |
| MBS Productions Limited | Information & communication | 2025 |
| Mbsk Ltd | Professional & scientific | 2020 |
| Mbspa Limited | Other services | 2022 |
| MBT Builders Ltd | Construction | 2018 |
| MBU Clinical Services Ltd | Health & social care | 2026 |
| MBU Enterprise Ltd | Wholesale & retail | 2019 |
| MBU Professionals Limited | Professional & scientific | 2018 |
| MBU Properties Ltd | Real estate | 2022 |
| Mbud Ltd. | Construction | 2015 |
| MBV Ltd | Financial services | 2021 |
| MC & S. Estates Limited | Administrative & support | 1949 |
| MC (Contracting) Limited | Construction | 2004 |
| MC Bike Motors Limited | Wholesale & retail | 2025 |
| MC Chase Service Ltd | Health & social care | 2019 |
| MC Construct Ltd | Construction | 2019 |
| MC Daid Bros Ltd | Mining & quarrying | 2015 |
| MC Olarte Ltd | Health & social care | 2022 |
| MC Overseas Limited | Wholesale & retail | 2014 |
| MC Union Ltd | Transport & logistics | 2024 |
| MCA Audit Limited | Professional & scientific | 2025 |
| MCA Wealth & Finance Limited | Professional & scientific | 2023 |
| Mcanny Ltd | Information & communication | 2025 |
| Mcats Holdings Limited | Financial services | 2023 |
| Mcats Immobiliare Limited | Real estate | 2023 |
| Mcats IT Limited | Wholesale & retail | 2020 |
| Mccabe Builders (London) Ltd | Construction | 2018 |
| Mccarthy Plumbing and Heating Ltd | Construction | 2022 |
| Mccoy Property Limited | Real estate | 2017 |
| Mcdermott Ltd | Construction | 2017 |
| Mce.London Limited | Construction | 2021 |
| Mceleney Plastering Limited | Construction | 2016 |
| Mcgeastlothian Ltd | Administrative & support | 2013 |
| Mcgrath Consultancy Limited | Financial services | 2016 |
| MCH Construction Ltd | Construction | 2016 |
| Mchim Limited | Construction | 2020 |
| MCJ Garland Properties Limited | Real estate | 2022 |
| MCJ Real Estate Ltd | Real estate | 2024 |
| MCK Homes Limited | Real estate | 2025 |
| Mckay Accountancy Ltd | Professional & scientific | 2018 |
| Mckay Property Lettings Limited | Real estate | 2020 |
| Mckay Property Management Limited | Real estate | 2014 |
| Mckenzie Sakowicz Property Consultants Ltd | Real estate | 2021 |
| Mckenzie's Estate Limited | Real estate | 2025 |
| MCL Construction Solutions Ltd | Construction | 2020 |
| MCL Interior Solutions Ltd | Construction | 2021 |
| MCL Mechanical & Electrical Ltd | Construction | 2022 |
| Mclaut Limited | Construction | 2025 |
| Mclean Real Estate Ltd | Real estate | 2021 |
| Mcmanamon Electrical Ltd | Construction | 2021 |
| Mcms Construction Ltd | Construction | 2025 |
| Mcnair Tourism Consultancy Ltd | Professional & scientific | 2024 |
| Mcnulty Management Consultants Limited | Professional & scientific | 2011 |
| Mcom Media Communications Ltd | Administrative & support | 2011 |
| MCP Consultants Limited | Administrative & support | 2012 |
| MCP Consultants Private Limited | Professional & scientific | 2014 |
| Mcph Limited | Construction | 2020 |
| Mcpherson Marketing & Sales Solutions Ltd | Wholesale & retail | 2018 |
| MCR Onsite Ltd | Other services | 2021 |
| MCS Micro Technologies Ltd | Information & communication | 2015 |
| MCT Partnership LLP | | 2012 |
| Mcturk Limited | Financial services | 2025 |
| Mcubeproperties Limited | Real estate | 2022 |
| MCV Services Ltd | Construction | 2022 |
| MD Alterations Limited | Wholesale & retail | 2018 |
| MD Ataie Limited | Professional & scientific | 2021 |
| MD Homes Holdings Limited | Administrative & support | 2012 |
| MD Homes LLP | | 2025 |
| MDA Apex Ltd | Professional & scientific | 2026 |
| MDA Global Finance Ltd | Financial services | 2021 |
| MDB Interiors Ltd | Professional & scientific | 2018 |
| MDC Nominee Services Limited | Information & communication | 2016 |
| MDD Housing Ltd | Real estate | 2025 |
| MDG Holding Limited | Financial services | 2023 |
| MDM Marble Masters Limited | Construction | 2024 |
| Mdmn Properties Ltd | Real estate | 2024 |
| MDS Group Ltd | Construction | 2026 |
| MDS Plus UK Ltd | Wholesale & retail | 2025 |
| Mdsl Limited | Manufacturing | 2007 |
| Mdusolution Limited | Information & communication | 2012 |
| MDW Media Ltd | Other services | 2023 |
| ME Consultancies Limited | Health & social care | 2014 |
| ME Sport Inc Ltd | Education | 2019 |
| ME4U Limited | Wholesale & retail | 2026 |
| Mead Drive Ltd | Real estate | 2025 |
| Meadow Lodge Limited | Extraterritorial | 2019 |
| Meadow Mill Limited | Real estate | 2020 |
| Meadow Neighbours Limited | Real estate | 1996 |
| Meadow View (Harrow-On-The-Hill) Residents Association Limited | Administrative & support | 1995 |
| Meadow View Acquisitions Limited | Real estate | 2022 |
| Meadowgarth Ltd | Wholesale & retail | 2023 |
| Mealcraft Limited | Information & communication | 2022 |
| Meals on Reels Ltd | Hospitality | 2025 |
| MEAN3 UK Ltd | Real estate | 2020 |
| MEC Lead Supplies Ltd | Wholesale & retail | 2021 |
| MED 360 Limited | Other services | 2017 |
| MED Dent Mentors Limited | Education | 2025 |
| MED Matters Ltd | Health & social care | 2011 |