| Maison Moti Limited | Other services | 1996 |
| Maison Moti Properties Ltd | Financial services | 2025 |
| Maison Sienna Limited | Professional & scientific | 2025 |
| Maiys Ltd | Real estate | 2025 |
| Maje Properties Limited | Hospitality | 2023 |
| Maje Relocation Ltd | Hospitality | 2023 |
| Majestic Finish Ltd | Construction | 2025 |
| Majid Tutors Limited | Education | 2025 |
| Majlis Shop Ltd | Wholesale & retail | 2023 |
| Makat Ltd | Wholesale & retail | 2024 |
| Makdag Ltd | Professional & scientific | 2024 |
| Make Bloom Limited | Professional & scientific | 2023 |
| Make IT Count Consultancy Services Ltd | Professional & scientific | 2024 |
| Make Properties Ltd | Real estate | 2022 |
| Makitaspareparts Ltd | Wholesale & retail | 2021 |
| Maksimov Builders Ltd | Other services | 2017 |
| Makts Ltd | Wholesale & retail | 2025 |
| Malabar Europe Limited | Wholesale & retail | 2007 |
| Malaguti Construction Limited | Construction | 2022 |
| Maldives Vacations Ltd | Hospitality | 2021 |
| Malfred Ltd. | Public administration | 2022 |
| Mali Ventilation Ltd | Manufacturing | 2020 |
| Malibay Ltd | Wholesale & retail | 2022 |
| Malik’S Aroma Ltd | Manufacturing | 2024 |
| Malios Technologies Ltd | Information & communication | 2026 |
| Malkoc Accountant Limited | Professional & scientific | 2021 |
| Malkram Limited | Information & communication | 2015 |
| Mall Homes Ltd | Real estate | 2023 |
| Maloney Energy Ltd | Construction | 2022 |
| Maloo Holdings Limited | Real estate | 2018 |
| Malsia Construction Ltd | Construction | 2025 |
| Maltbase Limited | Real estate | 1989 |
| Maltby Kebabs Limited | Hospitality | 2025 |
| Mama POT Ltd | Hospitality | 2025 |
| Mama's Taste Afro-Carribean Food Ltd | Wholesale & retail | 2025 |
| Mamali-Mirzaei Studio Ltd | Professional & scientific | 2018 |
| Mamarika Herbology Ltd | Manufacturing | 2022 |
| Mama’S Secret Ltd | Hospitality | 2025 |
| MAN & MAN Investments Ltd | Real estate | 2020 |
| Mandaven Ltd | Wholesale & retail | 2024 |
| Mandaven Rental Limited | Real estate | 2025 |
| Manful Construction Limited | Construction | 2015 |
| Mango Land Ltd | Wholesale & retail | 2020 |
| Mango Tree Productions Limited | Arts & recreation | 2012 |
| MANISA45 Ltd | Wholesale & retail | 2023 |
| Mann Bespoke Ltd | Manufacturing | 2025 |
| Manor Works Limited | Arts & recreation | 2024 |
| Manorial Office for -House- of House-Howard-Clarke for Caring and Supporting Services Limited | Professional & scientific | 2025 |
| Manorial Office for -House- of House-Howard-Clarke Housekeeping Services Limited | Professional & scientific | 2025 |
| Manorial Office for -House- of House-Howard-Clarke Limited | Professional & scientific | 2025 |
| Manorial Records Office for -House- of House-Howard-Clarke Limited | Professional & scientific | 2025 |
| Manovski Music Ltd | Information & communication | 2017 |
| Mans Health Care Limited | Health & social care | 2016 |
| Manu Music Group Ltd | Arts & recreation | 2023 |
| Mapak (Hoddesdon) Limited | Wholesale & retail | 2023 |
| Mapak Chemists Limited | Wholesale & retail | 1984 |
| Mapak Holdings Limited | Financial services | 2023 |
| Mapak Properties Limited | Real estate | 2019 |
| Maple & Wild Ltd | Wholesale & retail | 2021 |
| Mapleforce Limited | Real estate | 2004 |
| Mapleton Crescent Limited | Professional & scientific | 2023 |
| Mara Fashions Limited | | 1991 |
| Marakata Consulting Limited | Professional & scientific | 2025 |
| Maram Ltd | Construction | 2025 |
| Marathon Management Consulting Limited | Administrative & support | 2008 |
| Marathon Motors (Radlett) Ltd | Wholesale & retail | 2024 |
| Marayza Care Support Services Ltd | Health & social care | 2022 |
| Marble Fantasy INT Ltd | Construction | 2021 |
| Marblelissimo Ltd | Manufacturing | 2024 |
| Marc Alexander Services Limited | Transport & logistics | 2012 |
| Marc Dissanayake Limited | Health & social care | 2007 |
| Marcel&Mona Ltd | Construction | 2021 |
| Marco Transline Limited | Transport & logistics | 2013 |
| Marcus & Marcus Limited | Health & social care | 2002 |
| Marcus International LP | | 2016 |
| Marcus Kitchen & Bar Ltd | Hospitality | 2020 |
| Marego Limited | Health & social care | 2003 |
| Marenni Ltd | Wholesale & retail | 2022 |
| Maresia Spa Ltd | Other services | 2018 |
| Margaret Pratt Ltd | Professional & scientific | 2023 |
| Mari Engineering Ltd | Professional & scientific | 2020 |
| Maria & Davids Ltd | Real estate | 2025 |
| Maria Cleaning Services Limited | Administrative & support | 2016 |
| Maria Koleva Mortgage Consultancy Limited | Financial services | 2015 |
| Maria Properties London Ltd | Wholesale & retail | 2025 |
| Mariama Care Ltd | Health & social care | 2011 |
| Mariama's Little Stars Ltd | Health & social care | 2026 |
| Mariela&Kiril Ltd | Construction | 2014 |
| Marigold Projects Jamaica Limited | Manufacturing | 2017 |
| Marilicious Hair Ltd | Other services | 2024 |
| Marina Eastbourne Ltd | Hospitality | 2026 |
| Mario & SON Builders Limited | Construction | 2020 |
| Mario Boilers Ltd | Construction | 2021 |
| Marjana's Cleaning Services Limited | Administrative & support | 2024 |
| Mark D Campbell Limited | Professional & scientific | 2018 |
| Mark David Services Limited | Administrative & support | 2009 |
| Market App Limited | Information & communication | 2026 |
| Market Invest Ltd | Financial services | 2021 |
| Marketing Intelligence in Action Limited | Professional & scientific | 2017 |
| Markets Data Analytics Limited | Information & communication | 2016 |