| Manjula Catering Limited | Hospitality | 2015 |
| Manku Group Ltd | Households | 2026 |
| Mann Arora Property Ltd | Real estate | 2026 |
| Mann Empire Ltd | Real estate | 2025 |
| Mann IT Limited | Information & communication | 2017 |
| Mann MOT Ltd | Wholesale & retail | 2022 |
| Mann Residentials Ltd | Real estate | 2013 |
| Mann Trade Services Limited | Construction | 2026 |
| Mannabdellium Ltd | Construction | 2020 |
| Mannat Courier Ltd | Transport & logistics | 2022 |
| Mannat Transport Services Ltd | Transport & logistics | 2025 |
| Manodu Limited | Wholesale & retail | 2022 |
| Manor Direct Limited | Hospitality | 2025 |
| Manor House Mews Management Limited | Extraterritorial | 2012 |
| Manor Legal Limited | Administrative & support | 2019 |
| Manor Property Construction Limited | Construction | 2022 |
| Manor Stores OFF License Limited | Wholesale & retail | 2019 |
| Manpower Recruitment Limited | Administrative & support | 2023 |
| Manpreet Singh Brar Ltd | Manufacturing | 2026 |
| Manpreet Singh Logistics Ltd | Transport & logistics | 2026 |
| Manray Services Ltd | Professional & scientific | 2025 |
| Manroop Services Ltd | Transport & logistics | 2016 |
| Mansfield Burgers Ltd | Hospitality | 2025 |
| Manshaw Holdings Limited | Financial services | 2012 |
| Mantas 11 Limited | Professional & scientific | 2013 |
| Mantas International Limited | Professional & scientific | 2016 |
| Mantej Technologies Ltd | Information & communication | 2024 |
| Mantey Legal Services Ltd | Professional & scientific | 2024 |
| Manthan Puri Ltd | Construction | 2021 |
| Manu IT Services Ltd | Information & communication | 2025 |
| Manzar Ltd | Professional & scientific | 2011 |
| MAP Education Ltd | Education | 2025 |
| MAP Soft Solutions PVT Ltd | Other services | 2011 |
| Maple Auto Centre Ltd | Wholesale & retail | 2024 |
| Maple Construction Solutions Limited | Construction | 2025 |
| Maple Oak Accountancy Limited | Professional & scientific | 2019 |
| Maple Property Solutions Ltd | Real estate | 2025 |
| Maple Services Ltd | Administrative & support | 2021 |
| Maple Transport Ltd | Transport & logistics | 2026 |
| Maplebrook Care Limited | Health & social care | 2019 |
| Maples Care Home (Bexleyheath) Limited | Health & social care | 2010 |
| Maples Nominee Co 1 Limited | Extraterritorial | 2015 |
| Maples Nominee Co 2 Limited | Extraterritorial | 2015 |
| Maplewood Holdings Limited | Financial services | 2026 |
| Maplewood Project 01 Limited | Real estate | 2026 |
| Maplewood Taplow Limited | Real estate | 2026 |
| Maplewood Walpole Limited | Real estate | 2026 |
| Maplin Construction Ltd | Construction | 2025 |
| Maps Cargo Services Ltd | Transport & logistics | 2019 |
| MAQ3 Limited | Real estate | 2025 |
| MAQ5 Limited | Real estate | 2023 |
| MAR Facilities (Holdings) Ltd | Financial services | 2015 |
| MAR Facilities Support Services Limited | Administrative & support | 1999 |
| MAR Sleeva Health Care Limited | Health & social care | 2014 |
| Mar-Trans Ltd | Transport & logistics | 2025 |
| Mara Europe Ltd | Professional & scientific | 2026 |
| Maray Homes Ltd | Construction | 2023 |
| Marble Empire Limited | Manufacturing | 2018 |
| Marble Ideas Limited | Construction | 1992 |
| Marbles Kitchen Ltd | Hospitality | 2025 |
| Marc and Jason London Limited | Wholesale & retail | 2025 |
| Marcelo Consultancy Ltd | Health & social care | 2023 |
| MARCELTRANS1992 Ltd | Transport & logistics | 2019 |
| Marchmont Care Home Limited | Health & social care | 2007 |
| Marcopolo Group Limited | Wholesale & retail | 2024 |
| Marcopolo Holidays Ltd | Information & communication | 2012 |
| MARCTRANS77 Limited | Transport & logistics | 2016 |
| Marcus Transport Limited | Transport & logistics | 2015 |
| Mardore Holdings Ltd | Financial services | 2024 |
| Margalla Hills UK Ltd | Construction | 2021 |
| Marhaba Caffe Ltd | Manufacturing | 2025 |
| Maria Medical Solutions Limited | Health & social care | 2012 |
| Maria Rebecca Limited | Wholesale & retail | 2016 |
| Mariana Paun Ltd | Construction | 2020 |
| Marianiulica Company Ltd | Wholesale & retail | 2023 |
| Marianne Majerus Limited | Administrative & support | 2011 |
| Marigold Housing Limited | Real estate | 2026 |
| Marigold Summer Limited | Hospitality | 2016 |
| Marin RC Limited | Water & waste | 2021 |
| Marinov Painters Limited | Construction | 2010 |
| Mario Building Construction Ltd | Construction | 2012 |
| Mario DE Sousa Limited | Administrative & support | 2023 |
| Mario Logistics Limited | Transport & logistics | 2025 |
| Marisa Care Ltd | Health & social care | 2013 |
| Marish Court (Langley) Limited | Households | 1966 |
| Marjannafeh Limited | Wholesale & retail | 2020 |
| Mark Brown Ltd | Real estate | 2025 |
| Mark Cars Limited | Transport & logistics | 2017 |
| Mark Carter Limited | Other services | 2002 |
| Mark Finch Garden & Grounds Maintenance Limited | Administrative & support | 2010 |
| Mark IT Done Technology Solutions Ltd | Information & communication | 2021 |
| Mark Jones Recruitment Limited | Administrative & support | 2016 |
| Mark's Autocare Ltd | Administrative & support | 2013 |
| Markayl Construction Ltd | Construction | 2023 |
| Market Cube Ltd | Information & communication | 2016 |
| Market Hunt Limited | Professional & scientific | 2016 |
| Market Mart Ltd | Wholesale & retail | 2025 |
| Market Reach Limited | Wholesale & retail | 2023 |
| Market+ Ltd | Professional & scientific | 2004 |
| Marketing Better UK Ltd | Information & communication | 2022 |