| Medovar Ltd | Health & social care | 2021 |
| Medsec Group Ltd | Administrative & support | 2022 |
| Megasun (Buckley) Limited | Other services | 2006 |
| Mehdi's Buisness Ltd | Real estate | 2020 |
| Mei's House Ltd | Hospitality | 2026 |
| MEL J Software Ltd | Professional & scientific | 2024 |
| Melanie Byrne Legal Services Ltd | Professional & scientific | 2025 |
| Mele Music Limited | Other services | 2018 |
| Meli Tree Estates Ltd | Real estate | 2021 |
| Melita Healthcare Limited | Administrative & support | 2025 |
| Mellor Promotions Limited | Other services | 2004 |
| Melmel Limited | Real estate | 2018 |
| Melody Dean Pilates Ltd | Arts & recreation | 2016 |
| Melongold Limited | Hospitality | 1985 |
| Melow Hair Limited | Other services | 2026 |
| Melrose Woodwork Limited | Other services | 2017 |
| Melville Flat Management Company Limited | Households | 1982 |
| Melwood Building and Development Ltd | Construction | 2024 |
| Memopizza Ltd | Hospitality | 2025 |
| Mental Performance Coaching Ltd | Other services | 2026 |
| Meols Court Management Limited | Real estate | 2003 |
| Meols Drive Management Limited | Extraterritorial | 2010 |
| Meraki Sailing Ltd | Transport & logistics | 2026 |
| Mercadeo Limited | Professional & scientific | 2015 |
| Mercer Barbers Limited | Other services | 2026 |
| Merch HQ Ltd | Manufacturing | 2025 |
| Merchant FOX Limited | Information & communication | 2005 |
| Mercury I T Management Limited | Information & communication | 2004 |
| Mere Hall Conservation Association Limited | Households | 1972 |
| Merite Ltd | Hospitality | 2025 |
| Merlin Racing Limited | Arts & recreation | 2002 |
| Merlot Group Limited | Financial services | 2019 |
| Merlot Property Limited | Real estate | 2020 |
| Merselec Developments Limited | Real estate | 2025 |
| Merselec Fire Solutions Ltd | Construction | 2026 |
| Mersey Discovery 4X4 Ltd | Wholesale & retail | 2022 |
| Mersey Maids Ltd | Administrative & support | 2025 |
| Mersey Orthoplastic Group Limited | Education | 2016 |
| Mersey Plates Limited | Manufacturing | 2024 |
| Mersey Print Group Ltd | Manufacturing | 2021 |
| Mersey Red Property Co Ltd | Real estate | 2025 |
| Mersey Snooker Limited | Wholesale & retail | 2003 |
| Mersey Thai Community Interest Company | Arts & recreation | 2021 |
| Mersey View Investments Limited | Real estate | 2012 |
| Merseycare Community Transport Limited | Transport & logistics | 2008 |
| Merseyside Adventure Sailing Trust | Education | 2009 |
| Merseyside Contractors Limited | Construction | 2021 |
| Merseyside Homes and Property Limited | Construction | 2022 |
| Merseyside Properties LLP | | 2021 |
| Met-Arc Limited | Manufacturing | 1989 |
| Metanoeo Community Interest Company | Professional & scientific | 2015 |
| Meterflow Limited | Extraterritorial | 2005 |
| Metis Signal Ltd | Information & communication | 2025 |
| Metseraya Limited | Hospitality | 2025 |
| MF Finance Ltd | Professional & scientific | 2023 |
| MFP Groundworks Limited | Construction | 2021 |
| MFS North West Limited | Construction | 2017 |
| MH Plastering Wirral Ltd | Construction | 2023 |
| MH Steel Fabrications Ltd | Manufacturing | 2023 |
| MH Training Academy Ltd | Education | 2025 |
| Mhlc Ltd | Administrative & support | 2023 |
| MI Property Team Ltd. | Professional & scientific | 2010 |
| Michael Anthony @ Arena Ltd | Other services | 2011 |
| Michael FOX Marketing Ltd | Professional & scientific | 2026 |
| Michael Hayes Family Ltd | Other services | 2010 |
| Michael J Bennett Contracting Ltd | Professional & scientific | 2024 |
| MICHAELLITTLESERVICES23 Ltd | Construction | 2023 |
| Michaels Building & Joinery Services Ltd | Construction | 2021 |
| Michelle Manley Ltd | Professional & scientific | 2012 |
| Microai Limited | Information & communication | 2022 |
| Microbits Digital Agency Ltd | Wholesale & retail | 2022 |
| Microlink Technology Limited | Manufacturing | 1989 |
| Microspec Ltd | Manufacturing | 2005 |
| Middle Kingdom Ltd | Wholesale & retail | 2018 |
| Midland Building Commercial Ltd | Construction | 2022 |
| Mihalex Limited | Information & communication | 2022 |
| Mike O'Sullivan Garage Services Limited | Wholesale & retail | 2002 |
| Mileham Estates Ltd | Real estate | 2023 |
| Milestones Care Homes Ltd | Health & social care | 2005 |
| Millcroft Park Management Company Limited | Real estate | 1991 |
| Millennium Merseyside Limited | Hospitality | 2020 |
| Miller Book Keeping Limited | Professional & scientific | 2025 |
| Miller Homes (Wirral) Ltd | Real estate | 2016 |
| Millhouse Antiques & Collectables Limited | Wholesale & retail | 2004 |
| Millwrights (Liverpool) Limited | Construction | 1964 |
| Millys Estates Limited | Real estate | 2017 |
| Milo the Cat 2 Limited | Information & communication | 2022 |
| Milo the Cat Limited | Information & communication | 2019 |
| Mindful Resolutions Ltd | Administrative & support | 2018 |
| Mindful Wealth Management Ltd | Financial services | 2020 |
| Mindingme Psychologists Limited | Health & social care | 2015 |
| Miners Arms (Prospect) Ltd | Wholesale & retail | 2007 |
| Mini Magoos (Hannah Benson) Ltd | Education | 2024 |
| Mini Magoos Sensory Play Ltd | Education | 2017 |
| Minkk Hair Boutique Limited | Other services | 2015 |
| Mino Real Estate Limited | Real estate | 2016 |
| Miro Mediterranean Restaurant Ltd | Hospitality | 2023 |
| Miss Laura Jane’S Montessori Ltd | Education | 2025 |
| Missmacict Ltd | Information & communication | 2024 |
| Misted to Clear Ltd | Extraterritorial | 2012 |