| Maintenance Services Electrical Ltd | Construction | 2012 |
| Maisha London Ltd | Arts & recreation | 2025 |
| Maison Petalo Limited | Wholesale & retail | 2024 |
| Maisy May's Commercial Cleaning Services Limited | Administrative & support | 2023 |
| Maisy Mays Cleaning Services Ltd | Administrative & support | 2018 |
| Maja Ltd | Wholesale & retail | 2025 |
| Majar Property Invest Ltd | Real estate | 2021 |
| Majco Innovations Limited | Health & social care | 2020 |
| Majek Global Ltd | Real estate | 2023 |
| Majestic Decorating Limited | Construction | 2022 |
| Majestik Care Limited | Information & communication | 2013 |
| Majha Foods Ltd | Hospitality | 2019 |
| Majjha Transport Ltd | Transport & logistics | 2025 |
| Major (Northampton) Limited | Other services | 2003 |
| Major Industries UK Ltd | Wholesale & retail | 2019 |
| Major Sky Ltd | Professional & scientific | 2023 |
| Major Training Services Limited | Information & communication | 2023 |
| MAK NIK Transport Ltd | Transport & logistics | 2024 |
| MAK Trans Design Ltd | Transport & logistics | 2021 |
| Maka Properties (Northwest) Ltd | Construction | 2013 |
| Makanaka Electrical Services Limited | Professional & scientific | 2025 |
| Makart Ltd | Transport & logistics | 2011 |
| Make IT Real London Limited | Professional & scientific | 2015 |
| Make Movie OR DIE Ltd | Information & communication | 2026 |
| Make Sense Wear Ltd | Wholesale & retail | 2024 |
| Make Structures Limited | Professional & scientific | 2016 |
| Makemyday Recruitment Ltd. | Administrative & support | 2024 |
| Makeup Clearance Ltd | Wholesale & retail | 2025 |
| Mako Productions Limited | Construction | 2011 |
| Maks Trans Ltd | Transport & logistics | 2014 |
| Makwili Consultants Limited | Health & social care | 2023 |
| MAL Healthcare Ltd | Health & social care | 2023 |
| Malaga Tapas Ltd | Manufacturing | 2024 |
| Malai Consulting Ltd | Education | 2021 |
| Malarchyuk Ltd | Construction | 2025 |
| Malata Market Limited | Hospitality | 2018 |
| Malayali Aaanoo Limited | Information & communication | 2026 |
| Malb Holdings Ltd | Real estate | 2020 |
| Maldon Bespoke Landscaping Ltd | Construction | 2023 |
| Malet Limited | Professional & scientific | 2023 |
| Malevolent Pictures Limited | Information & communication | 2015 |
| Malfie Home Improvements Ltd | Construction | 2019 |
| Malik Express Cars Ltd | Administrative & support | 2025 |
| Malik Express Limited | Wholesale & retail | 2025 |
| Malin Precise Electrical Ltd | Construction | 2026 |
| Malina Investments Ltd | Real estate | 2022 |
| Malinowski Logistics Ltd | Transport & logistics | 2018 |
| Mallard Farms Limited | Other services | 2016 |
| Mallard Meadows Residents Management Company Limited | Households | 2024 |
| Mallard Property Investments Limited | Real estate | 2000 |
| Mallia Motorsport Ltd | Wholesale & retail | 2022 |
| Mallock Automotive Ltd | Wholesale & retail | 2026 |
| Mallows Court Freehold Limited | Real estate | 2016 |
| Mallows Court Residents Association (1994) Limited | Households | 1994 |
| Mally Chung Limited | Information & communication | 2017 |
| Maloney Plant Haulage Limited | Transport & logistics | 2004 |
| Malotobelu Investments Ltd | Real estate | 2026 |
| Malpas Property Services Ltd | Construction | 2016 |
| Malsher Properties Ltd | Real estate | 2024 |
| Malsor Ltd | Wholesale & retail | 2022 |
| Maltings Homes Limited | Construction | 2017 |
| Mamaia Store Ltd | Wholesale & retail | 2025 |
| Mamasandruby Ltd | Professional & scientific | 2026 |
| Mambo Digital Limited | Information & communication | 2018 |
| Mamebo Beauty Limited | Other services | 2018 |
| Mamlakha Limited | Real estate | 2022 |
| Mammoth Insulation Services Limited | Manufacturing | 2013 |
| Mamtej Limited | Wholesale & retail | 2022 |
| MAN Made Ltd | Other services | 2018 |
| MAN Private Limited | Administrative & support | 2024 |
| Man's SET Ltd | Manufacturing | 2021 |
| Mana Enterprises Limited | Transport & logistics | 2000 |
| Mana Performance Limited | Administrative & support | 2017 |
| Manascrew Ltd | Arts & recreation | 2019 |
| Manav & Reshav Ltd | Real estate | 2025 |
| Manchester Wings Limited | Financial services | 2007 |
| Mancraftuk Ltd | Extraterritorial | 2021 |
| Mandarin Buffet (Restaurant) Ltd | Hospitality | 2018 |
| Mandek Ltd | Construction | 2014 |
| Mandel Europe Limited | Wholesale & retail | 2002 |
| Mander Consultancy Limited | Professional & scientific | 2013 |
| Mandos by Tamina Ltd | Hospitality | 2019 |
| Mandrykin Property Management Ltd | Real estate | 2023 |
| Mandy Wicks Budgeting & Finance Ltd | Professional & scientific | 2023 |
| Manfred Sauer UK Limited | Health & social care | 2004 |
| Mangal Restaurant Ltd | Hospitality | 2025 |
| Mangata PAY UK Limited | Professional & scientific | 2022 |
| Mango House Care Ltd | Health & social care | 2019 |
| Mango M Limited | Transport & logistics | 2022 |
| Mani Greek Restaurant Ltd | Hospitality | 2024 |
| Manifest 888 Properties Ltd | Real estate | 2025 |
| Manilla Group Limited | Transport & logistics | 2023 |
| Manilla Healthcare Services Limited | Administrative & support | 2026 |
| Manilla Support Services Ltd | Public administration | 2024 |
| Manilla Ventures Homes Limited | Hospitality | 2022 |
| Manilla Ventures Limited | Administrative & support | 2019 |
| Manna House Investments Ltd | Real estate | 2023 |
| Mannafoods Ltd | Hospitality | 2022 |
| Mannering Europe Limited | Professional & scientific | 2003 |
| Mannering Styles Limited | Administrative & support | 2011 |