| Melo World Limited | Manufacturing | 2012 |
| Memphis Projects Ltd | Construction | 2016 |
| Meraki (UK) Holding Group Limited | Financial services | 2022 |
| Meraki Northwest Ltd | Hospitality | 2025 |
| Mersey School of Anaesthesia | Education | 2012 |
| Mersey Suites Limited | Hospitality | 2023 |
| Mersey Vent Holdings Limited | Real estate | 2015 |
| Mersey Vent Limited | Construction | 2010 |
| Mersey Wave C.I.C. | Arts & recreation | 2014 |
| Mersey Window Blinds Ltd | Wholesale & retail | 2018 |
| Merseycleanservices Limited | Administrative & support | 2026 |
| Merseyside Multi-Glazing Holdings Limited | Professional & scientific | 2010 |
| Merseyside Multi-Glazing Limited | Manufacturing | 1991 |
| Merton Beck Limited | Health & social care | 2005 |
| Merx Northwest Limited | Wholesale & retail | 2019 |
| Metal MAN LD Ltd | Manufacturing | 2017 |
| Metal Profiling and Engineering Products Limited | Wholesale & retail | 2012 |
| Metrics Corporate Clients Limited | Administrative & support | 2019 |
| MG Partnership Trade Ltd | Hospitality | 2009 |
| MGN77 Limited | Transport & logistics | 2020 |
| MH Accounting Services (NW) Ltd | Professional & scientific | 2025 |
| Mica Management Services Ltd | Construction | 2024 |
| Midnight Delivery Smithdown Ltd | Hospitality | 2018 |
| Mihai&Daniel Ltd | Transport & logistics | 2016 |
| MIHAIOANA17 Ltd | Transport & logistics | 2019 |
| Mike Mccann Ltd | Information & communication | 2016 |
| Milan CSM Trans Ltd | Transport & logistics | 2025 |
| Milan Serban Ltd | Transport & logistics | 2019 |
| Mill Brow Snooker and Social Club Ltd | Hospitality | 2018 |
| Millennium Car Parks Limited | Hospitality | 2015 |
| Millennium Care (U.K.) Limited | Health & social care | 1997 |
| Millennium Facilities Limited | Construction | 2011 |
| Millennium Property Enterprises Limited | Real estate | 2011 |
| Millennium Widnes Ltd | Hospitality | 2026 |
| Miller & Co Property Investments Limited | Real estate | 2025 |
| Millers News Limited | Wholesale & retail | 2025 |
| Millfield General Maintenance Ltd | Administrative & support | 2005 |
| Millies Medics Ltd | Health & social care | 2014 |
| Million Dollar Glow Ltd | Other services | 2019 |
| Millwood Manufacturing Ltd | Manufacturing | 2015 |
| Millwood Perfumery Limited | Manufacturing | 2020 |
| Milnes Investments Limited | Financial services | 1960 |
| Milton Engineering Company (Cheshire) Limited | Professional & scientific | 2008 |
| Milton Metals Limited | Manufacturing | 1995 |
| Mime CLO Ltd | Wholesale & retail | 2026 |
| Mina Nails & Spa Widnes Ltd | Other services | 2025 |
| Mindspring Digital Ltd. | Professional & scientific | 2024 |
| Mioara Haulage Ltd | Transport & logistics | 2024 |
| Mira Flowers UK Ltd | Wholesale & retail | 2025 |
| Mirage Stores Ltd | Wholesale & retail | 2005 |
| Miro Ltd | Construction | 2019 |
| Miro Property Investing Ltd | Real estate | 2020 |
| Mitchell's Financials Limited | Real estate | 2021 |
| MJ Renovate Ltd | Construction | 2021 |
| Mj's Travel NW Limited | Transport & logistics | 2020 |
| MJD and SON Plastering Ltd | Construction | 2022 |
| MJD Corporations Ltd | Wholesale & retail | 2025 |
| MJH Finance Ltd | Professional & scientific | 2017 |
| MJH Precision Engineering (NW) Limited | Manufacturing | 2012 |
| MJN Construction Ltd | Construction | 2012 |
| MJP Properties NW Limited | Real estate | 2024 |
| MJS Building Consultancy Ltd | Construction | 2026 |
| MK Best CUT Ltd | Other services | 2025 |
| MK Car Solutions Ltd | Wholesale & retail | 2014 |
| MK Valente Ltd | Health & social care | 2023 |
| MMC (NW) Limited | Professional & scientific | 2024 |
| MN Leasing Company Ltd | Real estate | 2026 |
| MOA Property Investments Ltd | Real estate | 2025 |
| Mobile Car Crafts Limited | Wholesale & retail | 2019 |
| Mobile Citi Ltd | Wholesale & retail | 2021 |
| Momentissue Limited | Manufacturing | 1992 |
| Momentus Limited | Professional & scientific | 2017 |
| Monarch Media Ltd | Professional & scientific | 2021 |
| Moneva Ltd | Hospitality | 2025 |
| MOO and a Brew Ltd | Hospitality | 2024 |
| Moon River Solutions Limited | Wholesale & retail | 1998 |
| Moor Lane MOT Centre Ltd | Wholesale & retail | 2019 |
| Moorfields Store Ltd | Wholesale & retail | 2023 |
| Morgan & Richmond Holdings Ltd | Financial services | 2025 |
| Morite Limited | Information & communication | 2010 |
| Motion Systems Limited | Manufacturing | 2004 |
| Motorcycle Parts Store Ltd | Wholesale & retail | 2022 |
| Motus Mortgage Limited | Financial services | 2025 |
| Mountain Wellbeing Ltd | Health & social care | 2025 |
| Mo’S Barber Widnes Ltd | Other services | 2025 |
| MP Piranetha Limited | Wholesale & retail | 2023 |
| MPD Garage Ltd | Wholesale & retail | 2025 |
| Mr&Mrs Paws Limited | Agriculture & fishing | 2020 |
| Mr-Rincon Services Ltd | Extraterritorial | 2025 |
| MS Beauty Saloon Ltd | Other services | 2023 |
| MS Valeting Limited | Other services | 2019 |
| MSD Widnes Ltd | Other services | 2025 |
| MSJSWAN1 Ltd | Hospitality | 2019 |
| MSS Trans Ltd | Transport & logistics | 2018 |
| Msshosp Limited | Administrative & support | 2016 |
| Mssind Limited | Administrative & support | 2016 |
| Msspay Limited | Administrative & support | 2016 |
| MSW Management Consulting Ltd | Professional & scientific | 2019 |
| Mtrs Properties Ltd | Real estate | 2022 |
| Mulberry Eighteen Limited | Real estate | 2019 |