| M & H Group Holdings Limited | Financial services | 2019 |
| M & L Management Limited | Administrative & support | 2007 |
| M & M Glazing Ltd | Wholesale & retail | 2010 |
| M a Ellis Developments Limited | Administrative & support | 2000 |
| M and G Fletcher Ltd | Financial services | 2018 |
| M C Kershaw Contracting Ltd | Agriculture & fishing | 2011 |
| M D Building North West Ltd | Construction | 2017 |
| M D Joinery (Southport) Limited | Construction | 2002 |
| M Forshaw Building Contractors Ltd | Construction | 2012 |
| M Forshaw Developments Ltd | Construction | 2007 |
| M H Projects Ltd | Construction | 2023 |
| M Hampton Services Ltd | Administrative & support | 2022 |
| M Hunter & Co Limited | Financial services | 1994 |
| M J Decorative Specialists Limited | Construction | 2018 |
| M J Taylor & SON Ltd. | Construction | 2006 |
| M L Foods Ltd | Wholesale & retail | 2017 |
| M O P Holdings Ltd | Financial services | 2019 |
| M P B Green Property Ltd | Construction | 2020 |
| M Rahman & Co (Accountants) Ltd | Professional & scientific | 2009 |
| M S Khaira Stores Limited | Wholesale & retail | 2018 |
| M Stanistreet Properties Ltd | Real estate | 2020 |
| M&Ck Ltd | Manufacturing | 2024 |
| M&E Pro Limited | Other services | 2019 |
| M&G Investment Properties Ltd | Construction | 2026 |
| M&J Roofing Ltd | Construction | 2016 |
| M&M Golda Properties Ltd | Real estate | 2025 |
| M&M Manufacturing Ltd | Manufacturing | 2024 |
| M&R Collins Property LET Ltd | Households | 2025 |
| M-Prove Consultancy Ltd | Professional & scientific | 2020 |
| M.D. Joinery (Upvc) Limited | Manufacturing | 2006 |
| M.G.G. Hadden & Co Limited | Extraterritorial | 2002 |
| M.L.F Property Developments Ltd | Real estate | 2025 |
| M.Nicol & Co.Limited | Manufacturing | 1902 |
| M.P. Laboratory Limited | Health & social care | 2014 |
| M.R.H. Group Limited | Other services | 1991 |
| M.V.C.Toma Ltd | Transport & logistics | 2016 |
| M1FUTURES Ltd | Information & communication | 2023 |
| M1Z Consultancy Limited | Public administration | 2015 |
| M4 Hotels Ltd | Hospitality | 2008 |
| M4 Logistics Ltd | Administrative & support | 2016 |
| M41 Developments Limited | Construction | 2018 |
| MA Consulting Solutions Ltd | Professional & scientific | 2015 |
| Maahrukh Fatima Limited | Hospitality | 2025 |
| MAB Horizons Ltd | Real estate | 2025 |
| MAC Digitals Ltd | Professional & scientific | 2014 |
| MAC Digitals Technology Limited | Construction | 2013 |
| MAC Motor Services Limited | Wholesale & retail | 2015 |
| Maccas Catering Ltd | Hospitality | 2026 |
| Mack Property Consultants Ltd | Administrative & support | 2026 |
| Macy JAY Limited | Health & social care | 2018 |
| MAD Building Services Ltd | Construction | 2019 |
| MAD Dog Training Club Limited | Other services | 2023 |
| Maddae Limited | Financial services | 2019 |
| Maddran Ltd | Other services | 2018 |
| Made Competitions Ltd | Arts & recreation | 2025 |
| Made to FLY Travel Limited | Administrative & support | 2015 |
| Madeira Brava Cafe Machico Ltd | Wholesale & retail | 2025 |
| Madeley Solutions Ltd | Construction | 2016 |
| Mademore Ltd | Professional & scientific | 2018 |
| Madison Leigh Property Group Limited | Real estate | 2019 |
| Magdalena Borowiecka-Fischer Ltd | Health & social care | 2013 |
| Magic Wand Software Ltd | Wholesale & retail | 2018 |
| Magiciansinblack Ltd | Arts & recreation | 2023 |
| Magna Nexus Developments Ltd | Construction | 2026 |
| Magna Payments Limited | Wholesale & retail | 2013 |
| Magnet Autos Ltd | Wholesale & retail | 2011 |
| Magnetic Group Limited | Arts & recreation | 2016 |
| Magnolia Property Enterprises Limited | Real estate | 2016 |
| Maguire Paint & Wallpaper Supplies Ltd | Wholesale & retail | 2005 |
| Mahendra Limited | Real estate | 2018 |
| Maid for YOU Cleaning Services Ltd | Administrative & support | 2025 |
| Mail and More Limited | Wholesale & retail | 2025 |
| Mail Order Online Ltd | Wholesale & retail | 2010 |
| Maintec Ltd | Manufacturing | 2003 |
| Majestic Floors Limited | Construction | 2001 |
| Major Movement Ltd | Transport & logistics | 2025 |
| Make Birth Better CIC | Health & social care | 2018 |
| Make IT Creative Southport Limited | Wholesale & retail | 2020 |
| Make IT Household Limited | Wholesale & retail | 2018 |
| Makeitcycles Limited | Wholesale & retail | 2018 |
| Makeitquick Ltd | Manufacturing | 2018 |
| Makeitrepair Limited | Other services | 2018 |
| Makeitworkshop Community Interest Company | Wholesale & retail | 2012 |
| Makeswa Ltd | Public administration | 2025 |
| Makin Ventures Ltd. | Health & social care | 2009 |
| Malcolm Banham Shopfitting Limited | Administrative & support | 2006 |
| Mali Thai Massage and Spa Ltd | Other services | 2016 |
| Maliha Food Ltd | Hospitality | 2024 |
| Malley Property Limited | Real estate | 2015 |
| MAM Financial Planning Limited | Financial services | 2021 |
| MAN Cave Mental Health Limited | Health & social care | 2025 |
| MAN to MAN Southport Limited | Wholesale & retail | 2014 |
| Manage Your Mind CIC | Health & social care | 2017 |
| Manchester Real Estate Holdings Limited | Financial services | 2018 |
| Manchester Real Estate Ltd | Real estate | 2013 |
| Manchester Removals and Storage Ltd | Transport & logistics | 2019 |
| Mandalay Property Holdings Limited | Real estate | 2016 |
| Mandalay Property Partners Ltd | Real estate | 2013 |
| Mandy Smith Ltd | Administrative & support | 2017 |
| Manis Superstore Ltd | Wholesale & retail | 2020 |