| M53 Motors Limited | Wholesale & retail | 1984 |
| M53 Truck & Plant Ltd | Wholesale & retail | 2015 |
| M@V Removals OR Waste Specialists Ltd | Water & waste | 2025 |
| Mabi VF Ltd | Manufacturing | 2026 |
| MAC Consulting Services Limited | Financial services | 2024 |
| MAC Northwest Limited | Wholesale & retail | 2017 |
| Mace Driving Limited | Transport & logistics | 2016 |
| Macgregor Law Limited | Financial services | 2023 |
| Machurian Limited | Information & communication | 2013 |
| Macktek Automation Ltd | Professional & scientific | 2014 |
| Macs Entertainment Limited | Wholesale & retail | 2023 |
| Macs Rentals Limited | Real estate | 2025 |
| Madame Monsieur UK Limited | Other services | 2026 |
| Mahgra Ltd | Manufacturing | 2021 |
| Maison Muse - Beauty Co Limited | Other services | 2017 |
| Manchester Area Property Sourcer Ltd | Real estate | 2020 |
| Manchester Swim School LLP | | 2014 |
| Mandopoly Ltd | Real estate | 2026 |
| Mankat Limited | Health & social care | 2024 |
| Mankus Limited | Wholesale & retail | 2025 |
| Marath Pillai Ltd | Real estate | 2023 |
| Marcon West Ltd. | Wholesale & retail | 2008 |
| Mariya (Ellesmere Port) Ltd | Hospitality | 2024 |
| Mark Baker Digital Services Limited | Professional & scientific | 2026 |
| Mark Duffey Recruitment Limited | Administrative & support | 2016 |
| Mark Furnace Delivery Ltd | Transport & logistics | 2025 |
| Mark Johnson PM Limited | Information & communication | 2009 |
| Market Weighton Dental Practice Ltd | Health & social care | 2021 |
| Markstrike Limited | Real estate | 1989 |
| Marriott Motorcycle Training Limited | Education | 2012 |
| Marshall Brothers Properties Ltd | Real estate | 2019 |
| Marshall Contracting Ltd | Construction | 2025 |
| Marshmallows Salon Group Ltd | Other services | 2026 |
| Massie and FOX Developments Limited | Real estate | 2007 |
| Masterplan Property Solutions Ltd | Real estate | 2024 |
| Matec Plant (UK) Limited | Wholesale & retail | 2013 |
| Mati Lettings Ltd | Real estate | 2025 |
| Matt Finish Kitchen Resprays Ltd | Other services | 2010 |
| Matt Leahy Limited | Professional & scientific | 2024 |
| Matthew & Michael Limited | Manufacturing | 2019 |
| Matthew Fleet Enterprises Ltd | Professional & scientific | 2023 |
| Matthew James Site Services Ltd | Construction | 2015 |
| MATTHEW.WILLIAMS90 Ltd | Hospitality | 2019 |
| Mattressgard Limited | Wholesale & retail | 2016 |
| Maville Properties Limited | Construction | 1961 |
| Maximus Midlands Limited | Wholesale & retail | 2017 |
| MAY Civils Ltd | Construction | 2022 |
| MAYAHOLDINGS282 Ltd | Transport & logistics | 2025 |
| Mayann Unique Design Sewing Services Limited | Wholesale & retail | 2015 |
| Mayflower Chinese Ltd | Hospitality | 2025 |
| MB Marine Services Ltd | Professional & scientific | 2023 |
| MB Your Little Blackbook Ltd | Professional & scientific | 2020 |
| MBJ Tech Ltd | Information & communication | 2019 |
| MBM Grand Ltd | Health & social care | 2022 |
| MC Surgical Services Ltd | Health & social care | 2016 |
| Mcallister and Black Limited | Information & communication | 2020 |
| Mccg Limited | Professional & scientific | 2026 |
| Mcck Limited | Construction | 2022 |
| MCH Intermediate Limited | Professional & scientific | 2012 |
| MCH Parent Limited | Professional & scientific | 2016 |
| Mckay Turner Consulting Ltd | Professional & scientific | 2025 |
| MCL Logistics Ltd | Transport & logistics | 2018 |
| Mcmillan 1960 Limited | Extraterritorial | 2014 |
| MCO Innovations Ltd | Information & communication | 2018 |
| Mcselfiemirror Ltd | Professional & scientific | 2018 |
| MD & NLD Property Ltd | Real estate | 2020 |
| MD Motorcare Limited | Wholesale & retail | 2010 |
| MD Rentals & Developments Ltd | Real estate | 2014 |
| MD Technical Consultancy Ltd | Construction | 2020 |
| MD Transport (NW) Limited | Transport & logistics | 2012 |
| Mdsuk Consultants Limited | Transport & logistics | 2021 |
| Meadow Sky Properties Limited | Real estate | 2021 |
| Med-Info Limited | Health & social care | 1989 |
| Medisleeve Limited | Manufacturing | 2025 |
| Mediterranean Group Ltd | Hospitality | 2026 |
| Medlet Property Services Ltd | Households | 2025 |
| Meducate.Health Ltd | Information & communication | 2025 |
| Medway Civil Engineering Ltd | Construction | 2024 |
| Mehrparvar Ltd | Wholesale & retail | 2022 |
| Mehrparvar Properties Ltd | Financial services | 2024 |
| Melfix Limited | Construction | 2009 |
| Melissa Cooke DHT Ltd | Health & social care | 2021 |
| Melissa Smith Facial Aesthetics Limited | Health & social care | 2020 |
| Meljones Collective Ltd | Professional & scientific | 2026 |
| Mellachervu Limited | Administrative & support | 2014 |
| Melt & Unwind Candle Company Ltd | Wholesale & retail | 2024 |
| Memeko Ltd | Wholesale & retail | 2024 |
| Menopause 360 Limited | Professional & scientific | 2020 |
| Mensch Rentals Ltd | Real estate | 2020 |
| Mercury Vehicle Solutions Limited | Financial services | 2009 |
| Merlin Architectural Ltd | Wholesale & retail | 2014 |
| Mersey Gynaecology Limited | Health & social care | 2012 |
| Mersey Surgical Limited | Health & social care | 2020 |
| Mersey Weigh Ltd | Manufacturing | 2002 |
| Merseyside Paper Supplies Limited | Professional & scientific | 2011 |
| Merseyside Swim School LLP | | 2016 |
| Metis Automation Limited | Manufacturing | 2010 |
| Metronome Jazz Bar Limited | Hospitality | 2025 |
| MG Design Studio Ltd | Construction | 2026 |
| MHF Procurement Services Ltd | Other services | 2018 |