| Maine Financial LLP | | 2008 |
| Mainland Leisure Ltd | Wholesale & retail | 2020 |
| Mainslane Limited | Professional & scientific | 2015 |
| Maintenance Point Homes Ltd | Real estate | 2022 |
| Maintenance Point Limited | Construction | 2017 |
| Maintenance Projects Ltd | Wholesale & retail | 2009 |
| Maisha Invest Limited | Information & communication | 2025 |
| Maison Belle Limited | Real estate | 2025 |
| Maita Engineering Ltd | Professional & scientific | 2011 |
| Maize ME Limited | Hospitality | 2025 |
| Majestic Tiles UK Ltd | Wholesale & retail | 2025 |
| Majoka Industrial Packaging Products Limited | Manufacturing | 2026 |
| Majoyo Ltd | Information & communication | 2019 |
| Majw Ltd. | Transport & logistics | 2022 |
| MAK 2 Associates Limited | Professional & scientific | 2018 |
| MAK Civils Limited | Other services | 2016 |
| MAK Construction Services Ltd | Professional & scientific | 2023 |
| Make IS Limited | Professional & scientific | 2017 |
| Make IT PAY Ltd | Information & communication | 2023 |
| Make IT SO Digital Ltd | Professional & scientific | 2019 |
| Make Note Limited | Wholesale & retail | 2022 |
| Makenji Consulting Limited | Information & communication | 2017 |
| Makeup Candy Ltd | Wholesale & retail | 2015 |
| Makeway Projects Ltd | Hospitality | 2026 |
| Making Progress CIC | Information & communication | 2026 |
| Makit Limited | Information & communication | 2023 |
| Mako (NW) Ltd. | Real estate | 2025 |
| Makok Limited | Wholesale & retail | 2026 |
| Makrai Solutions Ltd | Information & communication | 2021 |
| MAL Project Management Limited | Administrative & support | 2016 |
| MALACHI08 Limited | Administrative & support | 2016 |
| Malaya Resources Ltd | Administrative & support | 2025 |
| Malcolm Hughes Land Surveyors Limited | Professional & scientific | 1977 |
| Malgorzata Suchy Limited | Wholesale & retail | 2020 |
| Malham Financial Services Limited | Administrative & support | 2003 |
| Malhm Properties Limited | Real estate | 2022 |
| Maliga Ltd | Construction | 2023 |
| Malik Star IT Ltd | Information & communication | 2012 |
| Malila Consultancy Limited | Administrative & support | 2020 |
| Malini C Limited | Arts & recreation | 2019 |
| Maliston Holdings Ltd | Real estate | 2025 |
| Mallett Stonemasonry Limited | Other services | 2003 |
| Malpas Design Ltd | Professional & scientific | 2018 |
| Mals Computer Consultancy Ltd | Information & communication | 2013 |
| Malsharbaty Limited | Health & social care | 2023 |
| Maltridge Engineering Limited | Professional & scientific | 1997 |
| Maluxx Laundry Ltd | Administrative & support | 2025 |
| Mamars Artisan Bakery & Delicatessen Ltd | Hospitality | 2024 |
| Mamars BCD C.I.C. | Wholesale & retail | 2021 |
| Mambo Property Limited | Administrative & support | 2007 |
| Mammacubs Store Ltd | Wholesale & retail | 2024 |
| Mamta Imaging Ltd | Administrative & support | 2025 |
| MAN From Douglas Ltd | Information & communication | 2018 |
| Man-Flex Limited | Manufacturing | 1974 |
| Manaa Health Care Limited | Health & social care | 2024 |
| Managed Payroll Solutions Limited | Professional & scientific | 2017 |
| Managed Solutions for Education Ltd | Administrative & support | 2011 |
| Manan Limited | Professional & scientific | 1991 |
| Mancad Ltd | Administrative & support | 2021 |
| Manchester Ball Boys Ltd | Wholesale & retail | 2023 |
| Manchester Environmental Services Limited | Administrative & support | 2012 |
| Manchester Finance Operation Services Ltd | Financial services | 2025 |
| Manchester First AID Training Ltd | Other services | 2016 |
| Manchester Mint Properties Ltd | Real estate | 2024 |
| Manchester Recycled Aggregates Limited | Water & waste | 1999 |
| Manchesterai Ltd | Information & communication | 2026 |
| Mandabill Ltd | Real estate | 2023 |
| Mandarin Court Management Company Limited | Real estate | 2011 |
| Mandarin Wealth Limited | Financial services | 2021 |
| Mandate LLP | | 2022 |
| Mandeso Limited | Administrative & support | 2016 |
| Mandovi Solutions Ltd | Administrative & support | 2025 |
| Mane Engineering Limited | Administrative & support | 2024 |
| Mane Living Limited | Real estate | 2026 |
| Manesh Property Limited | Real estate | 2022 |
| Manestone Investments Ltd | Financial services | 2020 |
| Manex (UK) Limited | Professional & scientific | 1998 |
| Manifest Services Ltd | Professional & scientific | 2026 |
| Manik Star Limited | Information & communication | 2018 |
| Manish Sharma Limited | Real estate | 2020 |
| Manna Logistics Ltd | Administrative & support | 2025 |
| Mannah Holdings Limited | Professional & scientific | 2021 |
| Mannah IT Ltd | Information & communication | 2015 |
| Manor Consultants Limited | Information & communication | 2017 |
| Manor Digitech Ltd | Professional & scientific | 2019 |
| Manor Farm Power Limited | Energy | 2021 |
| Manor House Farm Equestrian Ltd | Agriculture & fishing | 2025 |
| Manor Stream Limited | Wholesale & retail | 2020 |
| Manta Drainage & Plumbing Services Ltd | Administrative & support | 2014 |
| Manuka Health Europe Limited | Wholesale & retail | 2006 |
| Maogani Ltd | Financial services | 2021 |
| Mapara Consulting Limited | Information & communication | 2011 |
| Mapi Solutions Ltd | Professional & scientific | 2017 |
| Maple Civils Ltd | Construction | 2020 |
| Maple Contracting Limited | Administrative & support | 2004 |
| Maplec Power Services Ltd | Construction | 2017 |
| Maponos Manufacturing Ltd | Manufacturing | 2025 |
| Mara Consulting Ltd | Administrative & support | 2022 |
| Marazure Limited | Professional & scientific | 2018 |
| Marbar Security Ltd | Construction | 2021 |