| MOA Services Limited | Professional & scientific | 2017 |
| Moades Catering Ltd | Hospitality | 2022 |
| Moat Development Limited | Construction | 2003 |
| Moat Homes Finance PLC | Financial services | 2011 |
| Moatenden Management Company Ltd | Administrative & support | 2024 |
| Mobile Bar Hire Limited | Hospitality | 2006 |
| Mobile Finance Collective Ltd | Administrative & support | 2024 |
| Mobile Ironing Services Ltd | Administrative & support | 2020 |
| Mobile Pet Foods Limited | Wholesale & retail | 1989 |
| Mobile Phone Screen Surgery Ltd | Other services | 2021 |
| Mobile Tyres 4 YOU Ltd | Wholesale & retail | 2020 |
| Mocden Limited | Financial services | 2012 |
| Mode Data Analytics Limited | Information & communication | 2019 |
| Mode Home Services Limited | Administrative & support | 2020 |
| Mode Property Investments Limited | Real estate | 2018 |
| Modern Empowerment Ltd | Wholesale & retail | 2025 |
| Modern Maintain Ltd | Construction | 2024 |
| Modern Roofing & Building Ltd | Construction | 2025 |
| Modern Roofing + Building Limited | Construction | 2025 |
| Modern Screws Limited | Wholesale & retail | 2007 |
| Modesq Limited | Wholesale & retail | 2025 |
| Modish DOT Ltd | Wholesale & retail | 2021 |
| Modupe Ltd | Administrative & support | 2017 |
| MOE Homes Ltd | Real estate | 2022 |
| MOE Properties Limited | Real estate | 2018 |
| Moepharm Ltd | Wholesale & retail | 2023 |
| Moje Services Ltd | Administrative & support | 2024 |
| Moji Labs Ltd | Administrative & support | 2024 |
| Mola Rain Ltd | Wholesale & retail | 2021 |
| Moladconsulting Limited | Professional & scientific | 2013 |
| Moland Limited | Real estate | 2020 |
| Molando Trading Limited | Wholesale & retail | 2024 |
| Molyneux Press Limited | Manufacturing | 2003 |
| Momento Consulting Ltd | Information & communication | 2023 |
| Momentum Building Services Engineering Limited | Construction | 2016 |
| Mommy Opossum Limited | Health & social care | 2020 |
| Momo Enterprise London Ltd | Administrative & support | 2019 |
| Momo Medical Ltd | Health & social care | 2025 |
| Monanj Consulting Limited | Information & communication | 2020 |
| Monarch Communications (S.E.) Ltd | Construction | 2014 |
| Monarch First AID Training Ltd | Education | 2019 |
| Mondial Trends Limited | Professional & scientific | 2015 |
| Mondo Munch Ltd | Wholesale & retail | 2025 |
| Mondus Waste Management Limited | Water & waste | 2020 |
| Moneem Limited | Real estate | 2022 |
| Moneoa Cribs Ltd | Wholesale & retail | 2021 |
| Moneta Global Ltd | Financial services | 2020 |
| Money Control Limited | Financial services | 2021 |
| Moneychoice Ltd | Extraterritorial | 2006 |
| Moni Services Ltd | Manufacturing | 2019 |
| Monika Kikola Ltd | Financial services | 2024 |
| Moniks Care Services Ltd | Health & social care | 2018 |
| Monisola Ltd | Manufacturing | 2021 |
| Moni’Que Fashion & Styling Ltd | Wholesale & retail | 2020 |
| Monkey Travel Co. Ltd | Administrative & support | 2022 |
| Monostream Limited | Construction | 2023 |
| Mont Rima Investments Limited | Real estate | 2016 |
| Montreal Ltd | Professional & scientific | 2025 |
| Montreaux Court Residents' Association Limited | Households | 1997 |
| Mooboo Retail Lapan Limited | Hospitality | 2021 |
| Moon Trade Ltd | Wholesale & retail | 2025 |
| Moons Healthcare Ltd | Health & social care | 2023 |
| Moonwalk Properties Ltd | Real estate | 2022 |
| Moore Financial Wellbeing Limited | Professional & scientific | 2020 |
| Moore Understanding Ltd | Other services | 2025 |
| Moore, Moore and Moores Limited | Professional & scientific | 2019 |
| Moormead Consulting Limited | Professional & scientific | 2026 |
| More Blessinz Limited | Other services | 2025 |
| More Site Services Ltd | Construction | 2019 |
| Morgan HR Services Ltd | Professional & scientific | 2007 |
| Moriah Ltd | Other services | 2020 |
| Morka Mission Limited | Financial services | 2024 |
| Morley Facilities Ltd | Construction | 2017 |
| Mormac London Ltd | Construction | 2020 |
| Morningplus Homecare Ltd | Health & social care | 2025 |
| Morris Invictus Properties Ltd | Real estate | 2021 |
| Mortgage Consultants Limited | Financial services | 2019 |
| Mortgage Find Ltd | Financial services | 2026 |
| Mortimore's Transport Limited | Transport & logistics | 1996 |
| Mortlock & Joyce Limited | Real estate | 2021 |
| MOS Translations Ltd | Professional & scientific | 2025 |
| Mosae Essence Limited | Wholesale & retail | 2025 |
| Mosgm Ltd | Administrative & support | 2015 |
| Moss Development Company Limited | Administrative & support | 2006 |
| Moss Electrical (NW) Co Limited | Wholesale & retail | 2011 |
| Moss Electrical Group Limited | Financial services | 2021 |
| Mossfabrics Limited | Manufacturing | 2020 |
| Mota Medics Limited | Wholesale & retail | 2023 |
| Motan's Ltd | Transport & logistics | 2025 |
| Motidas Limited | Information & communication | 2015 |
| Motorlink Limited | Wholesale & retail | 2006 |
| Motorque Limited | Wholesale & retail | 2021 |
| Motorteck Ltd | Wholesale & retail | 2022 |
| Motosh Limited | Other services | 2013 |
| Mottingham and Bromhedge Residents Association Limited | Households | 1996 |
| Motto Merchant Services Limited | Financial services | 2022 |
| Mount Residents Association Limited(The) | Real estate | 1966 |
| Mountain of Miracles and Holiness Church of GOD Ltd | Administrative & support | 2016 |
| Mountaintop Homes Ltd | Real estate | 2021 |
| Mountsfield Gardens (NO2) Management Limited | Households | 1997 |