| Mavo Services UK Ltd | Information & communication | 2014 |
| Mawa Consulting Limited | Information & communication | 2014 |
| Mawanga & Co Limited | Professional & scientific | 2019 |
| Mawblack Properties Limited | Real estate | 2021 |
| Mawgreen Holdings Limited | Financial services | 2023 |
| Mawgreen Investments Limited | Real estate | 2023 |
| Mawgreen Ltd | Construction | 2016 |
| MAX 16 Ltd | Construction | 2024 |
| MAX Education & Visa Services Limited | Education | 2022 |
| MAX Motors 2 Ltd | Wholesale & retail | 2010 |
| MAX Vehicle Rental Ltd | Administrative & support | 2020 |
| Maxey MOT Ltd | Wholesale & retail | 2026 |
| Maxey Properties Ltd | Real estate | 2025 |
| Maxgreat (Leicester) Limited | Wholesale & retail | 2009 |
| Maxi PAL Ltd | Wholesale & retail | 2020 |
| Maxi-Cool Limited | Manufacturing | 2017 |
| Maxim Speed Ltd | Wholesale & retail | 2016 |
| Maximise Engineering Enterprises Limited | Financial services | 2017 |
| Maximise Engineering Services Limited | Manufacturing | 2005 |
| Maxims Care Services Ltd | Administrative & support | 2023 |
| Maximum Nutrition Retail Limited | Wholesale & retail | 2026 |
| Maximum Progress UK Ltd | Transport & logistics | 2020 |
| Maximum Sofa Ltd | Manufacturing | 2016 |
| Maximus Tech Solutions Ltd | Manufacturing | 2020 |
| Maxwell Advisory Services Limited | Professional & scientific | 2020 |
| Maxximo Ltd | Transport & logistics | 2024 |
| Mayaba Virtual Assistance Ltd | Information & communication | 2026 |
| Mayaka 786 Ltd | Wholesale & retail | 2019 |
| Mayar Bison Ltd | Wholesale & retail | 2024 |
| Mayasofimedeea Limited | Wholesale & retail | 2023 |
| Mayberry Designs Limited | Extraterritorial | 2018 |
| Mayfair Cambs Ltd | Wholesale & retail | 2025 |
| Mayfair Executive Estates Ltd | Real estate | 2023 |
| Mayfair Furniture Clearance Ltd | Wholesale & retail | 2012 |
| Mayfair TIN Ltd | Real estate | 2023 |
| Mayflower House Childcare Ltd | Health & social care | 2024 |
| Maygleam Services Ltd | Administrative & support | 2025 |
| Maylee Barber Ltd | Other services | 2024 |
| Maynard Wren Limited | Health & social care | 2023 |
| Mayne Avenue Residents Company Limited | Households | 2001 |
| Mays Uniform Solutions Ltd | Other services | 2022 |
| Maytesh Services Ltd | Health & social care | 2022 |
| MAZ Resolutions Limited | Real estate | 2025 |
| Maze MH Ltd | Transport & logistics | 2015 |
| Maze MH Property Ltd | Real estate | 2018 |
| Maziar Service Ltd | Transport & logistics | 2016 |
| Mazzor Ltd | Transport & logistics | 2019 |
| MB Arctic Ltd | Transport & logistics | 2021 |
| MB Gateway Ltd | Real estate | 2021 |
| MB Groceries Ltd | Wholesale & retail | 2025 |
| MB Pipe Services Ltd | Manufacturing | 2014 |
| MB Shiny Clean Ltd | Administrative & support | 2023 |
| MB WMS Solutions Ltd | Information & communication | 2024 |
| MB59220 Technologies Limited | Manufacturing | 2025 |
| Mbeb UK Limited | Wholesale & retail | 2025 |
| Mbimz Holdings Limited | Financial services | 2024 |
| MBJ Transport Ltd | Transport & logistics | 2018 |
| MBT Asset Management Ltd | Real estate | 2015 |
| MBT Pharma Ltd | Professional & scientific | 2023 |
| Mbuzs Limited | Transport & logistics | 2014 |
| MC Benn Holdings Ltd | Real estate | 2024 |
| MC Construction Management Services Ltd | Construction | 2023 |
| MC Jacklin Ltd | Manufacturing | 2021 |
| MC- Excellent Care Ltd | Health & social care | 2024 |
| MC999 Ltd | Information & communication | 2023 |
| Mcbella Events Decor & Co Ltd | Hospitality | 2024 |
| Mcbella Ventures Ltd | Other services | 2022 |
| Mccaigs Recruitment Ltd | Administrative & support | 2026 |
| Mceu Limited | Manufacturing | 2015 |
| Mcfinlay Limited | Other services | 2011 |
| MCG Building Contractors Limited | Construction | 2009 |
| MCG Electrical and Mechanical Services Ltd | Manufacturing | 2019 |
| MCG Group (Peterborough) Limited | Financial services | 2018 |
| MCG Transport Ltd | Transport & logistics | 2019 |
| Mcgookin Brickwork Ltd | Construction | 2025 |
| Mcgreevy Consulting Ltd | Professional & scientific | 2015 |
| Mcintyre Compliance Services Limited | Administrative & support | 2006 |
| Mcintyre Court Company Ltd. | Real estate | 2013 |
| Mcintyre Electrical Holdings Limited | Financial services | 2019 |
| Mckenzie Family & Finance Ltd | Professional & scientific | 2025 |
| Mclaughlin Associates Limited | Professional & scientific | 1988 |
| MCM Trans Ltd | Transport & logistics | 2012 |
| Mcmm Ltd | Administrative & support | 2024 |
| Mcnamara Property Ltd | Administrative & support | 2021 |
| MCO Accountants Ltd | Professional & scientific | 2005 |
| MCO Nominees Ltd | Extraterritorial | 2022 |
| Mconsult Limited | Information & communication | 2006 |
| MCS Builders Limited | Construction | 2026 |
| MCS Design & Development Limited | Professional & scientific | 2013 |
| MCS Partitioning & Drylining Limited | Construction | 2009 |
| Mcvitty Media Limited | Administrative & support | 2020 |
| Mcws Properties Ltd | Real estate | 2019 |
| MD Facilities Management Ltd | Administrative & support | 2023 |
| MD Motor Group Ltd | Wholesale & retail | 2025 |
| MD Sales & Consultancy Limited | Information & communication | 2024 |
| MD Vehicles Limited | Wholesale & retail | 2024 |
| Md.A.L.Construction. Ltd | Construction | 2025 |
| MDC Flooring Limited | Construction | 2023 |
| Mdek Groundworks Ltd | Construction | 2021 |
| MDG Enterprises (Holdings) Limited | Construction | 2023 |