| Madison Film Ltd | Professional & scientific | 2023 |
| Maestro Property Solutions Limited | Real estate | 2020 |
| Magenium Limited | Professional & scientific | 2021 |
| Maggie Consultancy Services Ltd | Education | 2022 |
| Maggie Sottero Designs Ltd | Wholesale & retail | 1999 |
| Magical Circus LLP | | 2016 |
| Magical Spelling Limited | Education | 2005 |
| Magners Maintenance Limited | Wholesale & retail | 2022 |
| Magnesium Medical Ltd | Health & social care | 2023 |
| Magnolia Estate and Property Development Ltd | Construction | 2020 |
| MAH Advisory Services Ltd | Professional & scientific | 2024 |
| Maha Superstore Ltd | Wholesale & retail | 2022 |
| Maincad Ltd | Wholesale & retail | 2006 |
| Maindba Ltd | Information & communication | 2013 |
| Maisie Bones Ltd | Other services | 2025 |
| Maison Vintique Ltd | Manufacturing | 2025 |
| Maize Transport Ltd | Other services | 2023 |
| MAJ Marketplace Ltd | Wholesale & retail | 2024 |
| Majestic Hair Boutique Ltd | Other services | 2011 |
| Majestic Production Group Ltd | Other services | 2024 |
| MAK Imaging Ltd | Health & social care | 2025 |
| MAK P S Ltd | Construction | 2023 |
| Makas Hair Style Bromborough Ltd | Other services | 2025 |
| Make Change Limited | Professional & scientific | 2018 |
| Make Mortgages Easy Ltd | Financial services | 2022 |
| Make Your Own KIT Co Ltd | Wholesale & retail | 2020 |
| Makki Traders Limited | Other services | 2020 |
| Malarex Limited | Manufacturing | 2018 |
| Malbah Limited | Wholesale & retail | 2016 |
| Malcolm Haynes Limited | Arts & recreation | 2019 |
| Malen Consulting Limited | Information & communication | 2020 |
| Malmo Resources Limited | Construction | 2019 |
| Malooga AI Limited | Information & communication | 2026 |
| Malpoet Ltd | Financial services | 2012 |
| Maltech Young Ltd | Wholesale & retail | 2023 |
| Mammut Plant Hire Limited | Administrative & support | 2016 |
| Mandarin IT Ltd | Information & communication | 2015 |
| Mandora ELB Limited | Other services | 2025 |
| Manganese Motors Limited | Wholesale & retail | 2003 |
| Mango Fast Food Ltd | Hospitality | 2024 |
| Mango Roofing & Painting Ltd | Construction | 2021 |
| Manifest in Construction Ltd | Construction | 2024 |
| Manirut Ltd | Real estate | 2025 |
| Manna Foods Bistro Limited | Hospitality | 2026 |
| Mannerhaus Wallasey Ltd | Other services | 2026 |
| Mannifest Marketing Limited | Information & communication | 2025 |
| Manor Court (Greasby) Management Company Limited | Administrative & support | 2001 |
| Manor Court (West Kirby) Management Company Limited | Households | 1997 |
| Manor Cyber Security Ltd | Information & communication | 2020 |
| Manor Hill Trading Limited | Wholesale & retail | 2023 |
| Manton Court RTM Company Limited | Financial services | 2022 |
| Manuel Trading Company Limited | Wholesale & retail | 2009 |
| Manufacturing Performance Enhancement Ltd | Professional & scientific | 2024 |
| Manyskillz Limited | Information & communication | 2017 |
| MAP - Coffee and Lounge Ltd | Hospitality | 2023 |
| Mapd Engine Room Limited | Administrative & support | 2024 |
| Mapd Ventures Ltd | Administrative & support | 2019 |
| Maple Health Group Ltd | Health & social care | 2014 |
| Maple Properties North West Ltd | Real estate | 2025 |
| Maplewood Property LET and Rentals Ltd | Real estate | 2023 |
| Mapptal Ltd | Professional & scientific | 2020 |
| Marakia Limited | Wholesale & retail | 2023 |
| Marana Ltd | Professional & scientific | 2022 |
| Marchelle Property Ltd | Real estate | 2023 |
| Marcinlocum Ltd | Wholesale & retail | 2023 |
| Marcol Homes Limited | Construction | 2015 |
| Marcon Ltd | Professional & scientific | 2006 |
| Marcus James & Co | | 1997 |
| Marfold Medical Limited | Health & social care | 2025 |
| Marigold Fisheries Ltd | Hospitality | 2024 |
| Marimo Media Ltd | Information & communication | 2016 |
| Marine Barber Shop Ltd | Other services | 2025 |
| Marine Consultancy and Project Services Ltd | Professional & scientific | 2018 |
| Marine Metallurgical Consultants Limited | Administrative & support | 2006 |
| Marine Park Visual Electrophysiology Consultants Ltd | Health & social care | 2026 |
| Marine Specialised Technology Limited | Manufacturing | 2002 |
| Maritime + Engineering College North West | Education | 1998 |
| Marius Seven Limited | Construction | 2023 |
| Mariya Foods Limited | Hospitality | 2024 |
| Mark Lampkin Electrical Contractors Ltd | Construction | 2020 |
| Mark Tait Transport Ltd | Transport & logistics | 2019 |
| Marketing With Alessandra Ltd | Professional & scientific | 2024 |
| Markides Consultants Ltd | Professional & scientific | 2014 |
| Marklin Ltd | Wholesale & retail | 2015 |
| Marlborough Court Management (Harrow) Limited | Real estate | 2000 |
| Marldon Group Limited | Manufacturing | 1966 |
| Marley Controls Ltd | Construction | 2019 |
| Marlu Marketing Limited | Professional & scientific | 2022 |
| Marsam Limited | Information & communication | 2019 |
| Mart Gordon Ltd | Information & communication | 2010 |
| Martin H. Cooper Limited | Arts & recreation | 1983 |
| Martin Quirk Limited | Professional & scientific | 2026 |
| Martin Revill Ltd | Wholesale & retail | 2017 |
| Martina Waterman Ltd | Wholesale & retail | 2026 |
| MAS Heating & Plumbing Ltd | Construction | 2023 |
| MAS Property Maintenance Ltd | Construction | 2017 |
| Mascsolutions UK Limited | Information & communication | 2019 |
| Maskill Consulting Ltd | Professional & scientific | 2024 |
| Mason Foot and Ankle Ltd | Wholesale & retail | 2019 |
| Mason Forbes Consultancy Limited | Financial services | 2012 |